Building a Local Food Movement

Experimental prototype of my garden. Imagine the productivity
of the upper part with the lower part being more architecturally
pleasing. It could be built in stonework, brick, wood, gabions,
etc. It also works well with water features.

I have heard a lot of talk over the last several years about the need to completely overhaul our food system. In particular, the current model of industrial food, produced unsustainably and unhealthily, then shipped long distances to the final customer with no real transparency in how the food was produced is a fatally flawed system. We need a new model of local, regeneratively produced organic food made from a distributed system. There is great interest in changing to that model. In fact, I saw a TEDx talk by Kimbal Musk saying that solving this very problem could be the next boom, possibly even equivalent to the internet boom of the 1990s. The question is, what would that look like? How do you beat an entrenched system with trillions of dollars behind it. Perhaps more importantly, how do you get there? There is considerable infrastructure that would be needed to make that happen.

The first thing to pay attention to is supply and demand. Right now the demand is higher than ever. Awareness of the flaws in the current system is high and people want a solution. They want a solution that helps their health, the health of their children, and the health of the planet. The tricky part is how to deliver the supply. Right now the producers are just not there, or are few enough that they don’t really stand out in the market and aren’t finding their customers. There are so many more producers needed, though. Where are we going to get them? And how are we going to encourage them to get started? I think that the answer to all this is in a complex of businesses operating in its own form of a circular economy. Each business works within the usual business model of that type of business, but changes its practices somewhat to be a part of the bigger whole. Allow me to explain, but first, let me suggest a piece of technology that will make the whole thing possible.

We are in a golden age of technology. Technological advances are automating processes that could never before be automated. The automation that has happened so far has largely been damaging to the ecosystem as machinery and chemicals are used to replace the functioning of natural systems. Technology needs to be used smarter to replace human labor and support and accelerate natural ecosystem functioning. I have seen strides recently showing that machines are advancing to the point where they can do some of the selective harvesting that could previously only be done by human labor. I have been working on the other side of the equation, though, making a system that automates the care of the plants and accelerates ecosystem processes, making a garden that is low effort but still highly productive. I will talk more about that later when I have filed  the patent. For now let’s just assume that the technology will exist that will allow individual homeowners to make use of their back yards to produce huge amounts of organic, healthy food that has been produced very, very locally. Let’s also assume that this technology is effective enough that a garden only needs to be looked at and maintained once a week or less, something I have already achieved.

As I said before, the creation of a complex of businesses who act as their own circular economy could achieve the creation of local food production in urban areas. The core businesses in this model would be a landscaping business, a mushroom growing business, a professional office (containing at least a civil engineer, a landscape architect, and software engineers, though other professions could fit here as well), and a cafe/coffee shop/market.

The first to the plate is the landscaping business. At the start of the venture, these guys would operate like a regular landscaping business, with one small, but key modification. As they trimmed trees, they would separate the trimmings into a couple of categories and trim to specific sizes. I will get more into that in a minute. As the business grows and we begin to build gardens for people, the landscapers would be the team that builds and maintains those gardens. The landscaping team takes the trimmings that can’t be used elsewhere in the process and makes compost and biochar that could be used elsewhere. They could even seek out other innovative work. For example, here in Arizona, tamarisk trees are highly invasive along waterways. The landscaping team could seek out contracts to harvest this and use the wood as a part of the overall process.

The second business that would be needed would be a professional firm. Landscape architecture would be the first and most important profession needed. Most aquaponic and hydroponic setups that are being built today are pretty industrial looking, being composed of lots of white PVC and wires and other such functional parts. This is fine for hobbyists who tend to prefer this sort of look, but if this venture is going to expand into the back yards of average middle class people, it is going to need to be much more aesthetically pleasing. Also, specific functionality would be needed for the technology to function correctly and that needs to be properly designed. Likewise, engineers might be needed for certain aspects of the design, especially as the systems improve in connectivity. I envision gardens with sensors measuring moisture levels, water levels, pH, Nitrogen levels, and more. These sensors could be connected up via Arduino or Raspberry Pi controllers and not only run the system, but also connect to the internet so malfunctions can be detected from afar and corrected quickly. Software engineers would be needed to write and maintain this software and could also create the interface that homeowners would use to plan out their gardens. The software would compile the needs of the various clients and give those numbers to the landscaping team so they could start the required number of plants in the greenhouse, getting them ready to go out at planting time. There are other opportunities here, like using the knowledge gained from experience repairing and building ecosystems to improve or even change wholesale the practices of civil engineering and maybe even architecture.

The third business to the table would be a mushroom growing business. One of the principles that is important for this to work is the understanding that nature is so efficient that other forms of production can be added at various levels. For example, the woody debris collected from the landscaping business could be chipped and composted to make a rich soil. Or it could be used to grow mushrooms, then composted to make a rich soil. The end result is the same, but a new level of production is added in the middle. Growing mushrooms for sale is just the tip of the iceberg, though. A company called Ecovative is making innovative products using mushrooms, like an all-natural substitute for Styrofoam. It is a packing material grown on agricultural waste in any shape that is needed. It isn’t limited to packing material, though. It can be molded into any sort of shape. It could be used to insulate homes. Others are using mushrooms for other materials, like leather. A mushroom grower could also produce mushroom spawn for farmers so they could use mushrooms to process their own waste back into soil and give themselves an additional income. Even the garden system could benefit. A plug-and-play system could be developed and marketed to the DIY crowd to build in their own back yard. These could be packaged in an Ecovative-inspired packing material. With the addition of a couple of key additives, the packing material could be broken up and used as a major component of the starter soil for the new system.

The fourth business for this to work would be a combination café and market. As more and more homes buy into the system, there will be more locally available produce. With the team of landscapers helping, excess produce that the homeowner doesn't need could be sold as local, organic produce. A whole market could develop around the gathering and delivery of produce to the local market. As people see the advantage of using this to offset costs of production and even make a modest second income, they are incentivised to put more land into production and encourage friends to participate. As demand is better understood, homes could look up market conditions when planning out their gardens. Items that are more in demand could be grown in greater quantity. Urban gleaning could even take hold, with local harvesters collecting wild foods from public lands and selling them to the market. The café would act as a gathering place and hangout for customers and those interested in the movement. As more native foods are grown, the café could use them in its dishes to develop demand and even hold classes to teach people how to cook with them. The menu could change daily based on what is available and seasonal. With a couple of classrooms added on the perimeter, the space could be used for open classes and community space. The architecture could be integrated with living systems and the diners and customers could be surrounded by greenery. Mycobacterium vaccae could be integrated into the soil and the air could be filtered through the soil. This could give cleaner air and help give customers and employees a sense of peace, making it a nice place to hang out. Coffee grounds from the coffee shop portion of the café could be delivered back to the mushroom growing portion for further use and food waste could go back to the landscapers for composting. The mushroom growing business could provide mushroom kits for sale in the market so people could grow their own at home.

While those business form the core of this complex, there is plenty of room for other enterprises to fit in. For example, if the building had a garden on the roof, it could be an ideal place for a combined elderly/child daycare facility. The interaction between the age groups would be good for both and the interaction with gardens would also help the growth of the children and the mental health of the seniors. An artisan space would be welcome. Pottery could be made to create refillable mushroom kits. The list goes on and is only limited by the imagination and drive of those involved.

The only thing stopping this getting started right now is partners and funding. There is SO much work to be done to make this happen, but I believe that the market is ripe for this right now. I just need to find the right people to make this happen. Anyone know how to get in touch with Kimbal Musk? I think an idea like this might be just what he is looking for.

Phoenix ASH & Regrowth

For the last several months, I have been hinting at this grand project I have been working on. I have felt it more important thus far to lay the foundation to talk about some of the concepts being implemented onsite. But I think I am in pretty good shape right now in terms of concepts being out there, and before I jump into my next series of posts, I wanted to take a moment to talk about the project I am currently working on.

The site is called Phoenix ASH & Regrowth. It is a half acre site in the Sunnyslope area a little north of downtown Phoenix. The project is an attempt to achieve as high a level of self-sufficiency as possible while simultaneously repairing the ecosystem onsite. The project site will also serve as a demonstration site to help promote these ideas and make significant improvements on a wide variety of fronts including food production, nutrition, flood prevention, urban heat island effect, air pollution, economic resiliency, erosion control, biodiversity, and much more. To achieve this, nearly everything we do onsite is to achieve one of  two goals: 1) Restore soil carbon, and 2) Promote biodiversity. While this may sound a little overly simplistic, these two things, when working in conjunction, cause a cascade of healthy biological functions that achieve everything else.

Let me take a moment to describe how this cascade works. Increasing the amount of carbon in the soil does two things primarily. The first is that it increases absorption of rainwater. This increases biological activity and helps mitigate flooding. The second is that it increases the fertility of the soil. As I have explained previously, carbon in the soil feeds the soil biome and increases the fertility of the soil and the availability of nutrients in the soil. By increasing the available moisture in the soil and fertility of the soil, plant growth is encouraged. Remember, as a gardener, my job is not to take care of the plants. My job is to take care of the soil and the soil takes care of the plants.

Once we have widespread growth of plants, we move to the next level. As I have already mentioned, the driver of ecosystem processes is the cycling of living matter from one organism to the next. This is where diversity comes in. Different organisms make use of different food sources and bring different benefits to the system. Rather than trying to dig through the science of biological systems, most of which doesn’t really exist yet (don’t even get me started on the faults with reductionist thinking employed by modern science), it is best to let the ecosystem find its own healthy equilibrium. We do that by including everything in the whole. There really are no weeds. The only caveat is that they must provide more benefit than they detract. So a pine tree was removed from the site because all it provided was shade. Oleanders were removed because they are highly toxic. And there are a couple of weeds we remove because of toxicity. Otherwise, everything is welcome.

Once the plants are growing, each one is valued for the benefits it brings. Edibles are harvested for human consumption. Grass and forbs are used for forage for the animals. Dead leaves and grass are harvested for compost. Trees are pollarded to provide wood to build more soil. At each level, the plant material runs through its cycle and is returned to the soil, increasing soil carbon and helping plant growth and diversity.

So let me talk for a moment about the various methods we employ onsite to achieve all of this:

Holistic Management

Holistic Management, as taught by the Savory Institute, is more of a guiding principle. Everything we do is viewed through the lens of Holistic Management and its principles. It is through Holistic Management that we can make the best decisions for how to weave the myriad methods together into one cohesive structure. The site also serves as the Arizona Savory Hub (ASH) and the first urban demonstration site for the Savory Institute. We are very excited to demonstrate that Holistic Range Management, which is typically managed on large tracts of land in rural areas, can be applied in an urban setting.

Permaculture

Permaculture is another guiding principle. The permaculture core principles are also core values and guide what we do and how we rebuild a complete ecosystem onsite.

Animal Impact

Animal Impact, as described in Holistic Management is an important part of how nutrients are cycled through plants and back into soil. Right now, we just have chickens and are using them to process forage and create compost. However, long term plans include goats and sheep, and maybe even miniature cows or rabbits. Each animal will have its own impact on the ecosystem, improving diversity and nutrient cycling.

Organic Gardening

Organic gardening, in its ideal form, builds soil carbon, reducing the need for synthetic fertilizers, pesticides, and herbicides. By not using chemistry to manage a biological system, the biological system is allowed to flourish, encouraging diversity and growing topsoil. Everything we do onsite at Phoenix ASH & Regrowth is organic.

Composting

While some of the organic matter is either processed in place (as in animal impact) or allowed to lie where it falls, much of the organic matter produced onsite is processed through the composting facility onsite. This turns decaying organic matter into high quality topsoil more rapidly so it can be spread back out where it is needed most. In addition, we use the chickens (Animal Impact) to process the compost. This allows the chickens to feed off of whatever they deem edible in the compost, including insects that are attracted to the rotting material. It also allows their droppings to be immediately incorporated into the compost. This helps the compost get hot and complete its cycle quickly. And when it is time for the compost to be turned? The chickens help with that, too.

Rainwater Harvesting

At just 9” of rain a year, Phoenix is a desert. But with careful planning and a little infrastructure, the rain can be stretched really far. To do, this, we use two primary strategies at Phoenix ASH & Regrowth. The first is rainwater barrels. There are two rainwater barrels on each of the three buildings onsite. The two smaller buildings have smaller, flattened barrels that sit up against the building. These each hold a little over 500 gallons. On the largest building, there are two larger barrels, each holding about 2600 gallons. The smaller tanks are perhaps a little undersized for the areas they catch, and the larger tanks are a bit oversized. However, with a little planning and some plumbing, we are able to drain the smaller tanks into the larger as they fill up, assuring that no rain is lost. This water is used to water the gardens.

The second type of rainwater harvesting comes from offsite flow, or water that is flowing onto the property. The property has a wash flowing through it. While this was a major problem for previous owners, it is seen as an advantage at Phoenix ASH & Regrowth. With a little regrading, the site was turned into a series of retention basins. As each retention basin fills, it overtops into the basin below it. By doing this, all, or nearly all, of the offsite flow can be captured and stored in the ground. This has the added benefit of reducing downstream flooding. The best part is that the first basins built are already growing lots of vegetation and thus building soil carbon. The change in water infiltration is already visible, with no water standing in these basins a mere 24 hours after a big rain. The newer basins, which haven’t had much of a chance to grow vegetation yet, take 3 or 4 days to drain, even though they get less water.

Nitrogen Producing Trees

In desert ecosystems, and in particular degraded desert ecosystems, there is often a lack of nitrogen in the soil. This can be a limiting factor for the growth of plants and thus the ecosystem as a whole. Nitrogen producing trees, such as palo verde, acacia, and mesquite can make a big difference in this area. Not only do they fix nitrogen from the air and make it into a usable form, but many are well adapted to dry climates with poor soil. They are drought tolerant and fast growing.

Pollarding/Coppicing

As the trees grow, they produce a great amount of biomass. Every two years, the trees at Phoenix ASH & Regrowth are pollarded, and a few select trees are coppiced. The branches and twigs that are cut off are used for a variety of purposes. They are used as feedstock for growing mushrooms, some are used to produce biochar. The bulk are chipped to either produce mulch for various areas around the site or as a bulk carbon source in the compost bins. The biomass produced by pollarding and coppicing becomes a large portion of the biomass we use to feed the soil.

In addition, trees typically have a root structure that mimics the size and extent of the canopy above. When the tree is trimmed back, the tree abandons roots and pulls back, adding as much carbon down in the soil as is harvested from above.

Hugelkultur

Some of the branches that are either trimmed out or are the result of random pruning throughout the year are used to create new garden beds. This use of hugelkultur adds a long-lasting source of carbon to the soil and provides a lasting source of food for the soil biome where it is needed most.

Biochar

Woody debris that is too big for the chipper, unusable for mushroom feedstock, or otherwise scrap material is processed into biochar. The biochar is added to the compost. Once there, it collects nutrients through the processing process. Then it is added to the soil with the rest of the compost where it is used to improve soil quality in perpetuity.

Mycoculture/Mycoremediation

Growing mushrooms is difficult in the desert, but it can be managed. Mushrooms are used in the intermediary process between wood chips and soil creation and provide an additional product. We are also working to find ways to use mushrooms to improve degraded areas of the site. This is a technology that has a lot of potential and we are working on finding a way around the challenges to best make it work.

Aquaponics

Phoenix ASH & Rebirth is located in a very brittle environment and the bulk of the site is being managed with this in mind. However, many of our common vegetables require quite a bit more water, thus necessitating a non-brittle microclimate. In this interest, we are looking for technologies that help use the water resources available onsite to their maximum utility. Aquaponics has some great potential in this respect, being particularly efficient with both water and nutrients. However, as a soil-less technology, it doesn’t fit as well with the goals of the site. We are exploring other options to improve the technology to be more organic.

As you can see, we have a whole lot going on for just a half acre. But combined, these techniques work closely together to make some significant changes in a degraded environment. Please help me in spreading the word. If we can turn a half acre in downtown Phoenix into a productive food forest and organic farm, it can be done anywhere. We just have to have a way to get these concepts out there and teach people to implement them. This world is fixable, and it can be done using the techniques provided to us by nature. Let’s get on this.

Coppicing and Pollarding

My moringa trees pollarded for the new year

I recently read a great article about a concept that is new to me: coppicing and pollarding. The concept is that both are methods of pruning trees such that the wood is harvested continuously without damaging the tree. The branches are cut off at a smaller size and used for whatever they are needed for, usually firewood or crafting, like basket weaving. The only difference between the two methods is that coppicing is done at ground level while pollarding leaves a length of trunk that is topped. As far as method, I am assuming the central trunk is cut just above a junction in the first year. After that, multiple branches grow from just below the cut and those are left for several years until they are harvested. 

The more I learn about gardening, the more I realize that soil is a living thing and needs to be fed properly. Think of it like people, but with a longer metabolic cycle. While people's metabolic cycle is measured in days, soil's is measured in years. Adding synthetic fertilizer is like you eating a candy bar (well, crystal meth is probably a better comparison), where you get a quick rush and lots of energy, but then you crash afterwards. Compost is a little better, probably a little more like whole wheat bread. It is still a carb. The body uses it up, just a little slower. Wood, though, wood is the ultimate complex carbohydrate. And I don't just mean that metaphorically. Wood is actually a whole lot of sugar molecules chained together, just like starch. The only real difference is that those chains are a lot harder to break. Good chunks of wood will feed your soil for years and years. 

Coppicing and pollarding seem like a great way to get that wood. So how do you add it to the soil? Just grind it up and mix it in? Well, no. Adding sawdust directly to soil in large amounts can be deleterious to your soil. Surface area is the key. Sawdust and wood chips have a lot of surface area and mushrooms will jump in and take advantage of that, but in doing so they draw the nutrients they need to make that jump. They completely deplete the soil of available nitrogen, which is really bad for the plants.

On the other side of the spectrum, there is burying logs. A log over 8 inches in diameter can feed the soil for decades, but it won't release any nutrition at all for several years and when it does, it releases really slowly. Plus, if you don't plant it deep enough, that large chunk of wood just below the surface looks like a wall to a small plant and suddenly your plants don't have soil deep enough to meet their needs.

How I create garden beds. This one was inoculated
with king stropharia mushrooms

With coppicing and pollarding, you can generate a lot of small branches in the 1-2 inch range. Dug down into the soil, hugelkulture style, can give you soil a long burst of really good nutrition and really help build the soil web of life for 5 or more years. Plus, those branches can be used to grow mushrooms. The usual recommendation is to grow mushrooms on logs over 4 inches in diameter, but smaller logs will work if they are bundled tightly. Better yet, the branches can be inoculated and then buried once the mushrooms have taken hold, giving the gardener the ability to harvest several flushes of mushrooms from their consistently improving garden soil. 

The article mentions oak, hazel, ash, chestnut, and willow as good candidates for coppicing and pollardiing. From my experience, I can say that elm, palo verde, and elm would also be great. If you live in Arizona, scrub oak would be one of the best for coppicing. But there is a tree I have only recently been growing that I think could possibly be the best for this method: moringa. The moringa tree is an insanely fast growing tree. From a seed sprouted indoors in the spring, a moringa tree can reach 12-15 feet in height and have a trunk diameter of 2-3 inches. They are completely intolerant of frost, but in cold climates they grow fast enough to be treated as an annual. In warmer climates, if the root ball can be kept from freezing, they can die all the way back to ground level and grow back bigger each year. I have seen a tree get killed back to the ground by a 20 degree F cold snap, only to grow to over 15 feet tall and have a 3 or 4 inch trunk the next year. Plus, the pods they grow, which taste like asparagus, are only edible on new wood. If the tree is left full size, the pods that grow on old wood will be bitter. As you might imagine, any wood grown by a tree this quickly, isn't very hard. In fact, it about as soft as balsa wood. In the garden, it will probably last 2-3 years. That means that 5 trees could feed you and your garden for years to come. 

Primary vs. Secondary Decomposing Mushrooms

Shaggy manes, a great example of secondary decomposers

There are many different kinds of mushrooms out there, classified by their source of food. Parasitic mushrooms attack living organisms. Mycorrhizal mushrooms form a symbiotic relationship with plants, trading nutrients for sugar. But when it comes to the world of mushroom cultivation, the real species of interest are the saprophytes, the mushrooms that decompose dead tissue. But even those come in several different varieties. There are primary, secondary, and tertiary decomposers. Tertiary decomposers are mushrooms that live in soil, scraping out a living on the little scraps of nutrition they can find here and there. Very few are of culinary significance. Primary and secondary decomposers, on the other hand, are the species that compose the majority of our culinary mushrooms.

When a tree falls in the forest, it is the primary decomposers that move in and start the process of turning the body of the tree back into soil. Think about the trunk of a tree. While the tree is alive, there isn't much living inside the tree, besides the tree, of course. Plus, it is made of solid wood (weird how that works, eh?) and most living creatures can't penetrate through to get to the energy stored in the wood. Fungal species are quite adept at it, though, and among the mushrooms, there is still lots of competition for any new food source. Once the primary decomposer detects an available food source, it throws all its energy towards occupying it. Growth is very rapid and it grows a huge amount of tissue in a fairly dense concentration.

Once it has colonized what it can grab, the primary decomposer produces a flush of mushrooms, then proceeds to decompose as much of the food source as it can.

Chunk of wood that has been fully decomposed by white rot
fungus, still looks like wood

However, primary decomposers are not particularly complete in how much they decompose. Most are either brown rot fungus, which means they decompose the cellulose and leave the lignin behind, or white rot fungus, which means they decompose the lignin and leave the cellulose behind. Either way, the wood still looks pretty much like wood when the fungus is done with it. It is just a whole lot softer and lighter.

The secondary decomposer moves in and picks up where the primary decomposer left off. It certainly feeds on the cellulose and/or lignin that is left over, but it also decomposes the other compounds present in the tree.

The biggest difference between the two is the type of environment they prefer to grow in. The primary decomposer is adapted to the inside of a freshly fallen log. They prefer an environment with little to no competition. They produce ideally on pasteurized sawdust, straw, or something similar. Secondary decomposers are a little different. In nature, once the primary decomposers have finished, insects, soil bacteria, and all kinds of other organisms have started invading. It provides a richer micro-ecosystem. This is the preferred habitat of the secondary decomposers. Some won't even produce mushrooms in sterile substrate. Several even prefer a well-composted substrate that still has some woody/fibrous components to it.

The same piece of wood as above, just squeezed to show
how soft it is. It is ready for a secondary decomposer

As for how to tell the difference, just look at the growing requirements. If the mushroom will fruit off of just sawdust, vertical or horizontal surface, it is probably a primary decomposer. If it requires a casing layer and only fruits from a horizontal surface, it is probably a secondary decomposer. Examples of primary decomposers are shiitake (Lentinula edodes), oyster (both Pleurotus and Hypsizygus species), reishi (Grifola frondosa), and pioppino/black poplar (Agrocybe aegerita). Examples of secondary decomposers are button/portobello (Agaricus brunescens), king stropharia (Stropharia rugoso-anulata), and shaggy mane (Coprinus comatus).

Considering my current projects, what are the implications of this information? Well, the main thing is that when mixing mushrooms and gardening, the information about what habitat the mushrooms like is very important. So when you are doing it in aquaponics, like I am, there need to be some minor adjustments to how you do it. For example, if you are doing traditional aquaponics, using media, primary decomposers are going to be your best bet. But rather than sawdust/woodchip blocks, which is the usual preferred method, partially buried logs would be best. The worms would gobble up the blocks too soon, whereas they would do no appreciable damage to the logs.

On the other hand, if you are doing aquaponics with soil, both primary and secondary decomposers can be used. The primary decomposers will still do better in logs, but the active soil in an aquaponics system can be really beneficial for secondary decomposer mushrooms. Plus, they would add additional filtration for the water.

A little over a year ago I created a woodchip bed in my aquaponics system using king stropharia mushrooms. The results were better than expected. They obviously thrived in that environment. I intend to keep experimenting as often as I can manage. I think there are great combinations out there yet to be discovered.

Sequencing Projects

One of the problems with doing projects with living organisms is that they have a life cycle. At least most of them. Life keeps on living, and one constant of life is consumption. Nutrients get used up and need to be replaced. Living organisms need to be fed.

Such was the case with my favorite project to date. Originally, it was a mushroom log, home to a lovely colony of elm oyster mushrooms (Hypsizygus ulmarius). I picked the log especially for this project because it had many branches. The crook of each branch originally held an epiphytic plant. The base around the log was originally wood chips that the mushrooms consumed. Worms were added to help the process. When the soil was far enough along, I put plants in there. Watering the plants helped me remember to water the log. Spraying the epiphytes also sprayed the log. The decomposition of the log provided a constant supply of carbon dioxide to the plants. It was a big, happy system.

But that was about 5 years ago. In that time I have eaten many pounds of mushrooms. Some of the plants died. As the soil decomposed, I had to add more. I have recombined my plants to other places. Some of the epiphytes are back in soil elsewhere. In short, the project has lived its useful life.

However, the log is still there, with plenty of wood remaining. While it hasn't produced any mushrooms in 2 or 3 years, really only the center of the log was completely rotted out. The branches are still intact. I knew the center was hollow because if I added water to the cracks in the top of the log, it eventually came out the bottom. I was thinking that there was a possibility that the fungus was still alive in there and just needed moisture to the right portions to resume production. Or, possibly it is just time for the project to be sequenced to another mushroom.

The first step that was be needed was to find a way to get water to the interior of the log. Spraying the outside or watering the plants around the log was just not enough. I needed to find a way to apply water to the center of the log. My experience with previous spent mushroom logs told me that the top inch or two of wood on the top would be hard, barely decomposed wood. But underneath that, the wood would be soft, even pliable. So I decided to dig out the top of the log and make it into a pot for a plant.

The first trick was to find the right plant. First of all, I am pretty picky when it comes to plants. I don't like plants that everyone else has. I have a strong preference for unique, weird plants. So it had to be something unusual. The hollow center of the log meant that the pot will have excellent drainage, no matter how hard I try to keep it moist. But since the purpose of the project was to moisten the center of the log, I'll need to water frequently. I needed a plant that likes moist conditions, but prefers good drainage. Sounds perfect for a tropical epiphyte. As luck would have it, I happened across a staghorn fern (Platycerium sp.) at a garden center. My baby plant is only 6" wide and 6" tall or so. But this plant is a giant. It grows on the side of trees in tropical climates, sometimes growing to five feet across or more. It has two kinds of fronds. It covers its root ball with what are called shield fronds, which are round and tough. The main plant is composed of what are called fertile fronds that grow out from the plant and resemble the shape of a stag's antlers, which is where the name comes from. It is a dramatic plant that would look fantastic growing out of the top of a log.

The next step was to carve it out. As I suspected, the wood on top was still hard, but only about 2” deep. After that, it  broke off easily. Starting in the middle where it was softest, I used a chisel to carve it out, working my way outwards. I stopped carving about an inch from the edge of the log. I considered carving it down farther than what naturally broke off, but I figured 2” deep was enough. It gave me plenty of space for soil and what little root ball the plant had.

Interestingly enough, the interior of the log was hollow. Completely. There was a 2” or so diameter cylinder right down the center of the log that had nothing whatsoever in it. I went ahead and filled that with the wood I had removed from the log. The hole took almost all of it. Then I filled the new “pot” I had made with animal-sterilized home made compost and planted my new plant.

The next step was to put another mushroom on the log. As luck would have it, I had just harvested two Pioppino (Agrocybe aegerita) mushrooms from one of my other logs. As a white rot fungus that loves cottonwood, I thought it might be a good choice for a mushroom sequencing of the project. I cut the stem butts off of the mushrooms and planted them at the base of the compost. Then I made sure I watered the whole thing very well for the next several days.

Now it has been a few months since I planted the fern. It has obviously been happy in its new home. The fern had no shield fronds when I planted it. It now has several shield fronds that are about 3” in diameter and the fertile fronds have continued to grow and expand. All in all, I am enjoying my log’s new look. As for the mushrooms, well, we’ll just have to wait and see on that one. I have no idea if the mushrooms grew or the mycelium took hold. And I really won’t until it produces that first flush of mushrooms. But that uncertainty is a way of life when it comes to growing mushrooms. You just get used to it.

Changes

On the morning of March 6^th, my wife and I decided to separate. That afternoon, I got a call that my nearly two-year long search for a job had finally paid off. I live in Prescott, Arizona, and the new job will be down in Phoenix, so I will be moving as well. Now, obviously, there are lots of major life changes that go along with all that. But for those of you who are gardeners, you know that “where am I going to garden,” while not the most important question, is certainly on the list.

I currently live in a house, and while I don’t have a yard to garden in, I do have enough room for a container garden. Down in Phoenix, I will most likely be getting a small apartment. Having a garden in the ground won’t really be an option. If I have a patio or porch, it will still be difficult to have a garden. The extreme heat in Phoenix in the summer means that container plants need to be watered up to three times a day to keep from drying out. So how does one who is driven to grow edibles do it in such an environment?

Obviously, it will depend on where I end up living. Ideally, my small apartment will hold my modest amount of furniture with a little extra room to spare. I am thinking of building what amounts to a small indoor greenhouse, though the glazing would be less for heat retention and more for moisture retention.  Vegetables typically require 6-8 hours of direct sun a day, a near impossibility indoors. So I am thinking of switching to something a little more apartment-friendly: mushrooms.

I could turn my greenhouse into a big, indoor mushroom grow room. It would have vertical racks for growing logs or sawdust blocks. At the top it would have a water tank (maybe even with a few fish in it) and a bubbler. The bubbles exiting the water would carry humidity with them, raising the humidity in the greenhouse. I would buy a number of air plants and attach them wherever I could to help cycle the oxygen a little more effectively. A few carnivorous plants would go a long way to keeping the gnat problem to a minimum as well.

Obviously, this idea is still in its infancy and will develop considerably before I have a chance to build it. As for my other greenhouse, we will be selling the lot I had planned to build it on. It isn’t off the table, though. Just stalled. I may end up building one down in Phoenix somewhere. Who knows? It is a whole new world out there!

Pioppino Mushrooms

Pioppino buttons - notice the different colors at this stage.

I have been growing mushrooms at home for many years now and I have tried a lot of different mushrooms. Pearl oyster mushrooms (Pleurotus ostreatus) are the easiest, aggressively growing on just about anything that is wood or was once made of wood (no conifers, though), and producing regular flushes. Elm oysters (Hypsizygus ulmarius) are my favorite for my experiments. They look and taste about the same as the pearl oysters, but get along much better with my plants than the pearl oysters. The pearl oysters have killed every plant I have ever tried to put in a pot with them. Cinnamon cap mushrooms, also known as brick tops (Hypholoma sublateritium) narrowly edge out pearl oysters as the most productive mushrooms. I quit growing them because I don’t really like the flavor, though they did make the best cream of mushroom soup I have ever had.

But my favorite, flavor wise, has got to be pioppino mushrooms, also known as black poplar mushrooms (Agrocybe aegerita). Ultimately, despite all their other great uses, I grow mushrooms as food, and there is something to be said for growing the best. After all, that’s the primary motivator for gardeners everywhere, right? The freshest lettuce. The perfect tomato. The hottest pepper. The tastiest mushroom.

Over the years, pioppino mushrooms have proven themselves to be a difficult mushroom to grow. The books I have recommend that it be grown horizontally on a log. That is sort of a tough sell inside as I grow most of my mushrooms vertically on logs in pots. Pioppino mushrooms are native to the southeastern United States, so I figured they would do well with the outside heat in my northern Arizona home. I tried growing them on a bed of logs in a shady spot on the north side of my house. They failed, though I suspect it was more a lack of humidity. I tried growing them on coffee grounds, which is a great method for both kinds of oyster mushrooms, and they never took hold. I have tried growing them on wood chips and they have proven to be finicky about leaping off into the wood chip matrix.

A few years ago, I got my hands on a couple of cottonwood logs. Pioppino mushrooms have a strong affinity for members of the poplar family, of which cottonwood is a member. So I got a pioppino block and got a couple of fruitings out of it (always a good step to maximize your harvest). Then I took a couple of 10 gallon aquariums and cut the logs to the right size to fit inside lengthwise. I filled them with sawdust, cut a few wedges out of the log to help the mycelium get to the interior of the log, and inoculated the whole batch.

After about six months or so, when I was reasonably sure the mycelium had moved into the logs, I added a handful of red worms to each pot and added a few plants, a clivia and an amaryllis to one and a calla lily to the other. The worms broke down the woodchips to make soil for the plants. The plants draw the water out of the bottom of the aquariums, which don’t have a drain. Instant ecosystem!

After a year or so, the log in the pot with the calla lily began to produce mushrooms. It has produced small flushes (usually one or two mushrooms) pretty consistently for the last year or more. But I never got any mushrooms from the other log, leaving me wondering if the inoculation was successful.

This morning, I got my first mushroom from the other log. It is still small, so I will have to watch it carefully to make sure it is the right kind of mushroom, but early indications are positive. If it has indeed taken off, that means I now have two logs that are growing pioppino mushrooms, an accomplishment that I am particularly proud of.

The interesting thing about it, though, is the location from which it is growing. As you can see from the picture, it is coming up from the base of the clivia. Now that could just be coincidence, or it could indicate some sort of close association there. The clivia is extremely healthy, so the mushroom is obviously not causing it any harm. It is definitely something I will be keeping an eye on.

Wood Chip Mushroom Spawn

If you buy any kind of mushroom kit online, except portabella, it will most likely come in the form of a 5lb block of wood chips grown through with mycelium. The reason for this is simple. Wood chips are easy to colonize for mushrooms, a nutritious food source, and a convenient medium for transfer. One of the best things about growing mushrooms on wood chips is that they can be fruited up to three times and then used to transfer mushrooms to a new substrate. In fact, it really doesn’t matter (for most mushrooms, that is*) whether you bought the block for transferring mycelium to a new medium or for producing mushrooms. It can first be fruited and then broken up and used as spawn.

Growing mushrooms on wood chips is pretty easy. First you need to match the wood with the preferences of the mushroom. Then you need to get the wood into the right form. Sawdust tends to be to fine and packs a bit too tightly for optimal mushroom growth. Large wood chips tend to have too much air flow for the mushrooms to grow well from one to the next. A good mixture of the two (about 20% chips to 80% sawdust or fine wood chips works best. If you have a chipper that grinds them fairly small but not quite sawdust, like I have, it works well as is. Just don’t use wood shavings from your pal’s wood shop. Even if they use the right kind of wood, the curled shape keeps the shavings from packing very well and the mushrooms don’t grow well on it.

The next step is to pasteurize the wood chips. You want to get the wood chips up to about 180 degrees F and leave them there for an hour to kill pathogens. Then you need to get mushrooms growing on it. Other wood chip spawn works quite well. You can also use stem butts or even plug spawn. Then grow it like you would any mushroom block. When it is ready, you fruit the block a few times and then break it up onto your next substrate. That can even be more wood chips.

Just realize that every time you transfer mycelium, you run the risk of contamination.

*Notable exceptions are Coprinus comatus (shaggy manes) and Stropharia rugoso-annulata (king stropharia), which require a casing layer to produce mushrooms, Polyporus tuberaster (stone mushroom), which forms a sclerotium, and Morchella species (morels), which are just weird.

Spore Mass Slurry

Wood chips 2 weeks after addition of spore mass slurry

Nature seeks equilibrium. This is a concept that can be seen throughout natural systems, but nowhere more evidently than in reproductive rates. Ideally, a natural system, in its most natural state, is in perfect equilibrium. Each individual in the system seeks to replace itself, no more, no less. Sure, all organisms would like to increase their numbers and increase their success, but gone unchecked, this is the path to starvation and disease. Averaged across a population and over centuries, a population in balance with the rest of its environment will average one successful (in this case successful means “grows to adulthood and reproduces”) offspring per mature individual.

Looking at a species’ reproductive strategy can tell you a lot about their place in the ecosystem. Top predators, like wolves and big cats most directly reproduce one to one. Sure, many offspring are produced, but accidents and disease are taken into account and not much else. Rabbits are prey animals. They can produce dozens of offspring in a single year and hundreds in a lifetime. They pay a heavy price to predation, and this must be taken into account in the reproductive strategy. An oak tree can live for hundreds of years. Once it reaches maturity, it can produce thousands of acorns every year. Its reproductive strategy takes into account the squirrels (who plant the acorns) eating most of each year’s crop as well as mortality of oak seedlings.

Mushrooms have among the worst reproductive success out there. A mushroom with a decent source of food can live for 10 years, sometimes much, much more. Each year it can produce dozens of mushrooms. Each mushroom is capable of producing billions (yes, that big number is plural) of spores. Only two spores are needed to reproduce; they must land near each other on a food source, germinate, and then mate to produce a healthy mycelium. How is it that each individual must produce literally trillions of spores to simply replace itself in the ecosystem? Personally I think it speaks to the inefficiency of spores as a reproductive strategy. There is a reason plants moved away from spores and towards seeds as a reproductive device. Spores are just not very effective or very efficient at producing offspring.

Often when I speak to friends about growing mushrooms, their first question is “where do you get the spores?” I have to explain to them that nearly all mushroom cultivation is done by the direct transfer of mycelium from one medium to the next. This is  because it is so difficult to successfully and reliably achieve reproduction from spores. However, there are times when spores are available and a good medium for what you are trying to achieve. It is for those times that it is useful to have a method for utilizing the spores that gives them the greatest chance for success. That is when we use a spore mass slurry. A spore mass slurry was a method developed by mycologist Paul Stamets as a way to spread spores over a wide area in a way that helps give them a head start.

The first step is to acquire spores, and that is the hard part. Usually, the best way to acquire spores is from a spore print. If the spore print is taken on glass, the spores can be dried, scraped off, and stored. If the spore print is on paper, the paper can be dried, folded, and stored. You can also add the mushroom directly to the liquid once it has cooled, letting it soak, gills (or pores) down for 4 hours, letting it release its spores directly into the liquid. I have gotten lucky recently and have come across some Coprinus comatus (shaggy mane mushroom) spores. Normally, when shaggy mane mushrooms come up, they quickly deliquesce into an inky, gooey mess, and are gone. Here in Arizona, the exterior of the mushroom dries before the process can complete. The interior still deliquesces, though, only to dry on the inside of the cap. The hollow mushroom that results can be stored. When the spores are needed, it can be immersed. Once wet, the mushroom will deliquesce the rest of the way and the spores will disperse into the surrounding liquid with ease.

Water with molasses and salt added and mushrooms to be added

The actual recipe for a spore mass slurry is quite simple. Take one gallon of rainwater (filtered tap water or distilled water will also be fine, but beware of water straight from the tap as it has too much chlorine here in the US) and bring it to a boil. Add one tablespoon of molasses and one quarter teaspoon of salt. The salt helps inhibit the growth of bacteria that would normally happily consume the protein-rich spores. The molasses gives the spores a little sugar and other nutrients and entices them to begin germinating. Once the mixture is complete, boil for 10 minutes. Then take off heat and cool until it has reached room temperature.

Spore mass slurry after 48 hours

Once the liquid is cool enough, you can add your spores. Let the liquid sit in a cool corner of your house for 24-48 hours. Once it has sat long enough to begin germinating, pour the slurry directly on your substrate. Don't leave the slurry in its liquid form for much more than 48 hours, though, as oxygen and nutrients run out. Also consider that mycelium is a terrestrial organism, not an aquatic organism. It likes the liquid to get started, but it really needs wood or soil to grow properly.

Personally, I prefer the use of a spore mass slurry over a mushroom kit for more dispersed growing. For example, many mushrooms are great additions to the garden or compost bin. A spore mass slurry is a good way to spray germinating spores across a wide area and, provided you have access to spores. It can also be a lot less expensive and easier than inoculating with wood chip spawn. You just have to take failure rates into consideration.

Cardboard Mushroom Spawn

One of the great things about growing mushrooms is that growing materials are often free. Sometimes they even save you from throwing things away. Using cardboard as mushroom spawn is one such example. Cardboard is made of raw, unbleached paper, which is a good growing material for mushrooms and the corrugations are held together with a glue that is also very digestible by mushrooms. The channels in corrugated cardboard give the mycelium an easy channel to run down and travel quickly.

Personally, I find that mushrooms produced on cardboard tend to be kind of anemic. The open structure, while ideal for travelling mycelium, isn’t really dense enough to produce lots of mushrooms. However, the sheet form that cardboard comes in makes for easy transfer from one medium to another. If you are making a wood chip mushroom bed, you just lay down a layer of wood chips, then cover it with your cardboard spawn and then add another layer of wood chips, for a total of about 6” thick. You can use cardboard spawn for making mushroom logs as well. You take a chainsaw and cut a wedge in the log, line it with your cardboard spawn and hammer the wedge back in. When making a mushroom block out of wood chips or coffee grounds, you can just tear up the cardboard and mix it in. It will spread from the cardboard.

Making cardboard spawn is really easy. The first thing to do is find a good source of cardboard. Something that has already been through the mail is fine, as long as it isn’t covered in grease or other such toxic or unidentifiable chemicals. Cardboard spawn is best grown rolled up, so a container that will fit a roll of cardboard, like a glass jar or a bucket, works nicely. Then cut the cardboard to fit your container.

The next step is to clean the cardboard to remove potential contaminants. The nice thing about cardboard is that it is a pretty hostile environment, so you don’t need to worry about too many contaminants unless it has bee sitting outside for a long time. The biggest thing you need to worry about is mold spores. You will need to get rid of those. There are two basic ways to do that. The first is with boiling water. Put your cardboard in its container and fill it with boiling water and put on a lid if it has one. Let it sit about an hour. That will kill almost all mold and bacteria. The problem is, it also dissolves the glues, destroying the structure of the cardboard.  Fortunately, there is a second method involving hydrogen peroxide.

As many mushrooms grow, they naturally want to claim territory that they occupy as their own. One major source of possible competitors is spores of other fungi. Most mushrooms produce various peroxidase compounds as they grow. These compounds destroy the spores without harming the mycelium. Hydrogen peroxide is a very similar compound to what the mycelium produces and has much the same effect. So I will put some hydrogen peroxide in a spray bottle (or just transfer the spray nozzle to the peroxide bottle) and spray the cardboard down. I don’t dilute or anything. The hydrogen peroxide will break down into water pretty quickly and won’t harm the mycelium in small amounts.

Once the cardboard is treated, you can just layer your previous spawn on top. Wood chips from a spent mushroom block is a good medium of transfer. I also find stem butts particularly effective for transfer onto cardboard. Either way, you lay it on top and then roll it up as tightly as you can. Then put it somewhere and keep it moist. It is ready to transfer when the entire surface is covered with white, cottony mycelium and it no longer smells like wet cardboard.

Oh, and when you are finished transferring it to its new home, consider setting aside one sheet of cardboard. You can roll it in a fresh sheet of cardboard to make all new cardboard spawn.

Coffee Ground Mushroom Spawn

There is a fine line between a medium that is used for mushroom spawn (that is, to transfer to another medium) and one that is used as a growing medium. Some, like cardboard, are more structurally suited to transfer and may not have enough nutrition to take the mycelium all the way to a bountiful flush of mushrooms. Others, like straw, which is messy and difficult to fully sterilize, are more suited to fruiting and less good for production of spawn. Coffee grounds is one that is good for both. The granular nature of the grounds makes for quick and easily colonization by the mycelium. The process of making coffee out of the grounds conveniently sterilizes the growth media, limiting the opportunities for contaminants. The woody nature of the seed pod of the coffee bean also provides good woody material as well as abundant nutrition for the mycelium. Another nice feature is that most coffee filters are made of paper, which is also readily digestible by mycelium.

The first trick is to find a suitable mushroom to grow on coffee grounds. I have had great luck with both Pleurotus ostreatus (pearl oyster mushrooms) and Hypsizygus ulmarius (elm oyster mushrooms). I am currently attempting it with Agrocybe aegerita (pioppino/black poplar mushrooms), but my stem butt was small and it hasn’t made much progress yet. I suspect that there are other mushrooms that would do well in this medium as well, but not being a coffee drinker, I don’t have too much opportunity to try out new combinations. Also, I prefer to start my coffee ground cultures with stem butts from fresh mushrooms. If you are a one-pot-a-day household, this method works really well.

The method for growing mushrooms on coffee grounds is really easy. Wait until your coffee grounds are cool enough that they are no longer steaming, but not quite cold and put one pot worth of grounds, including the filter, in a bag or jar. Nestle the stem butt (or a little sawdust spawn, or whatever spawn you are using) into the center of the coffee grounds. In about two days, the spawn will recover from the transfer and will have visible signs of growth, in the form of a white, fuzzy coating. From there, you can add more coffee grounds at the rate of about one pot a day. Again, the coffee grounds should still be warm, but not warm enough to burn your hand. You add coffee grounds as the mushroom grows. If you start to get too far ahead of the mushrooms, as evidenced by a lot of uncolonized grounds in your container, stop adding for a few days until the mycelium catches up. The mycelium should more or less colonize the grounds after they have been in there just a day or two. If it takes much more than that, contamination can become a problem.

Moisture is another issue. Often coffee grounds have residual liquid in them. Mycelium can’t really colonize substrate that is under water. If I am using a gallon Ziploc bag, I will just pour the liquid out as it accumulates. In a glass jar, however, the liquid can be used for another purpose. Glass jars have less air flow than a bag that can be fully opened. When the jar is full, you can get fresh air down to the mushrooms if there is a little liquid in the bottom by just turning it upside down. As the liquid travels through, the pores in the material will be filled with air, which naturally has to be drawn from other areas. Just open the jar to get a little fresh air in the top, then turn it over and let it sit a few hours. Then turn it over again. Just don't do this before the jar is full as it will disturb the mushroom too much.

Overall, the container should be opened once a day to give the growing mushrooms a source of air. Usually this is accomplished when you open it to add the coffee grounds for the day. You can also give the mushrooms air flow by using a canning jar and replacing the sealing portion of the lid with a coffee filter (unused) or a piece of fabric.

Just keep the jar in a cool, dry location while it is growing. Once the jar is full and the mycelium has fully colonized it, as evidenced by the fact that it is all cottony-white and no longer smells like coffee, it can be used as spawn to transfer to another medium or it can be just fruited. To fruit it, give it another week or so to grow, and then open up the jar. Put it out in the light, but don’t put it in direct sun. Put a plastic bag over it as a tent, but punch a few holes in it for air flow. Then spray it a couple of times a day. Personally, I know a lot of people like to try to force the process, but I like to let the mushroom tell me when it is time. When, in the process of your daily airings, you see primordia, tiny baby mushrooms that look like pinheads, you will know it is time to fruit the mushrooms. You should get two or maybe three good fruitings out of a jar and maybe more out of a bucket.

Once the medium is done fruiting, you can still use it as spawn to start another kit. You can mix it with more coffee grounds, or just compost it again and start with another stem butt.

Propagating Mushrooms

Mushrooms are hardy organisms. The mycelium of a mushroom producing fungus is capable of living for hundreds of years, perhaps more. For example, there is a patch of Armillaria mushrooms in Oregon that is believed to be over 2,000 years old. However, most of these magnificent organisms rarely live more than a few years. This is because of fungus’s way of eating. It grows into its food source and lives there until the food is gone. Unless it has another nearby source of food to grow into, it will starve to death and die. The art of propagating mushrooms is primarily the art of transferring the mycelium from one food source to another to keep it going as long as possible.

There are several ways to propagate mushrooms. In commercial production, they work under sterile conditions and take a sample of mycelium, either from the center of a fresh mushroom or a stored mycelium, and grow it onto agar in a petri dish. Then they transfer it onto sterilized rye grains (sometimes more than once) and then transfer it to pasteurized straw or wood chips for the final production of mushrooms*. However, in most people’s homes, mine included, sterile conditions are a bit hard to come by. So I will talk a bit about methods you can use that don’t require sterile conditions.

What we are going to be making is called spawn. Spawn is a growing medium for mushrooms that is used to expand a sample taken from living mycelium in preparation for making something larger for producing mushrooms. There are many kinds of mushroom spawn, and selection of such depends on what you have on hand and what you are hoping to transfer mushrooms onto. For example, mushrooms that are going to be transferred onto a log might be cultivated in a different form than mushrooms that are going to be transferred to a wood chip bed. Below are some common kinds of mushroom spawn out there and a brief description. I will cover some of them in detail later in individual posts.

Plug spawn – Plug spawn is made from wooden dowels that are grown through with mushrooms and then hammered into logs.

Coffee ground spawn – Coffee ground spawn takes advantage of the fact that coffee grounds are small, easily colonized and pre-sterilized.

Cardboard spawn – Cardboard spawn makes a nice surface to sandwich between two layers and makes an ideal growth medium for mushrooms.

Bunker spawn – A large mass of myceliated material covered in a protective cloth coating is good for helping mushrooms leap off in less-than-ideal conditions.

Wood chip spawn – Wood chips give an easy medium on which to grow and expand mushrooms.

*Note that this is how most gourmet mushrooms, such as oyster and shiitake, are grown. Button mushrooms have different requirements and are grown on composted, pasteurized steer manure.

A Strategy for Growing Mushrooms

Imagine, if you will, a huge table in the forest. On this table, Mother Nature has laid out every kind of food you can possibly imagine. Meats, fruits, and vegetables of all kinds are all laid out and waiting to be eaten. Plants make their own food, so they have no need to come to the table. Animals have the great advantage of mobility and are the first to arrive at the feast. The animals hit the easy to digest, high energy foods, like fruits and meats, first. But they also take most of the vegetables and just about everything that is readily digestible. By the time the animals have finished, all that is left is scraps. The bacteria and the molds come next. Actually, they were always there as they are always everywhere in nature. They have limited abilities of movement, but their real advantage is their ability to multiply rapidly. However, by the time they reach sufficient numbers, the table is all but clean. No matter, the bacteria move in and consume the scraps left by the animals.

The very last diner to the table is the fungi perfecti, the mushroom producing fungus. They come in blown by the wind or they grow to the table through the soil. Either way, it takes them a week or more to get to the table and amass any appreciable size where they can really take advantage of the food. By this time, though, even the scraps are gone. This doesn’t really bug the mushrooms, though. They just settle right in and eat the table.

This mental image is what drives my designs for mushroom habitats. When growing a plant, you want to create the optimum conditions for that plant to grow, thrive, and out-compete whatever competition it will have. The same thing goes for growing mushrooms, remembering that their principal competition will be bacteria and molds. To do that, you need to control some key environmental factors to give the mushrooms the competitive edge.

Temperature

Bacteria typically grow best in warm conditions. That is why your refrigerator is cold. It inhibits the growth of bacteria. The same goes for molds. Tropical mushrooms, like pink oyster and paddy straw mushrooms need warm conditions to grow properly as well. However, most temperate mushrooms are well adapted for cooler temperatures. In nature, they live on the cool forest floor. Many, especially the enoki mushroom (Flamulina velutipes) are so well adapted to the cold that they will continue to grow in any temperature short of actually frozen. It is a strategy that serves them well. Mushrooms that can continue to grow in cooler temperatures can continue to grow and survive when their principal competition has gone dormant. Growing your mushrooms in cooler conditions (though not actually in the fridge) can help them out-compete bacteria and molds.

Moisture

One of the advantages of being a multi-cellular organism is the ability to transport nutrients from where you have them to where you need them. Now fungus isn’t as good at this as us vascular animals, but it can transport water small distances. It can also survive through fairly dry conditions (though complete desiccation will probably kill it) and come back to life when water is again available. Keeping your mushroom just a little damp, but not overly wet, will allow the fungus to grow without giving the bacteria the upper hand.

Food Sources

This is the area where you can really stack the deck in favor of the mushrooms. Many of the best gourmet mushrooms are primary decomposers of wood. That means that they will move into a solid log and consume it. Raw, unprocessed wood is a complete food for mushrooms. Now you could probably get better and faster growth by adding all kinds of additives. Mushrooms like sugar as much as the next organism. However, the more other stuff you add to give it more energy, the more you open the door to other organisms to move in and compete. Keeping the meal as hard to digest as possible gives the mushroom the advantage.

Surface Area

Controlling the surface area of your food source is another way to cut down on contamination in your mushroom cultures. Consider a log vs. a pile of sawdust. The sawdust is much more accessible to the mycelium. The mycelium can grow through it in just a few days and then begin digestion in earnest. On the other hand, the bacteria and molds around can also do that. A fresh log, on the other hand, is a solid block of hard material. The mycelium uses a combination of digestion and hydrostatic pressure to push its way through, but doesn’t leave much room for others to slide in behind it. It may take 6 months for the mycelium to colonize the whole log, but provided it wasn’t contaminated to begin with, you have a good chance it won’t become so in that period of time.

So just consider the various factors that are within your control when you are setting up the growing conditions for your mushrooms. A little tweaking of the conditions could mean the difference between a successful culture and lots of yummy mushrooms and a contaminated failure that is only good for the compost bin.

Growing Mushrooms vs. Growing Plants

Someone once described war as “long periods of boredom punctuated by brief periods of terror.” Change “terror” in that sentence with “excitement” and you have a pretty good description of growing mushrooms. With a plant, the seed sprouts and then gets a little bigger every day until it reaches maturity. With a little careful observation and an eye for detail, you can see the daily difference. You get a little satisfaction every day.

Growing mushrooms is quite different. When you start a culture, say with a stem butt, it sits for a day or two. Then it gets a little fuzzy. After a few days of the fuzz getting a little longer, all of a sudden it starts growing rapidly. It covers the surface of the substrate in long strands at a rate of an inch or more a day under ideal conditions. Then, behind the leading edge, the webbing starts to fill out, claiming everything as its own. In just a few days, the surface is covered with a white blanket. Then it sinks in.

After the initial push, the white sort of goes away; it is like it dives down into the substrate to eat. At this point, nothing really happens for weeks to years at a time. If it is a log, it will take 6 months to a year or more before anything else happens. If it is something like sawdust spawn or coffee grounds, it will only take a month or so. During that period, it won’t change a bit. You can look at it all you want, but you won’t see any change.

Then, one day, something new appears. They are called primordia and they look like little pinheads on the surface. They show up overnight, sometimes by the dozens and start to grow. They expand in size and get taller. When they get about a quarter of an inch tall, they stop growing and dry up. I liken this step with testing the water. Maybe the first batch didn’t have the right mixture to survive in this environment, but in my experience, the first flush of primordia almost always abort. A day or maybe two later, a second batch will show up. This one has the right conditions. Pretty soon the primordia have grown into buttons and the buttons have grown into full grown mushrooms. The whole process, from primordia to full grown mushrooms usually takes about 5 days, sometimes less, occasionally more for large or woody mushrooms. It is very exciting. Sometimes you can come back and see noticeable growth after just a few hours. Talk about instant gratification! And when the process is done, you get to eat the results. You just can’t beat that.

A Compost Project

In addition to a trash dumpster and an oversized recycling bin, my neighborhood has a compost bin. It has two large bins that are big enough that one can be composting while the other handles waste from the entire neighborhood. It also has a central section with a roof that is used to store bales of straw that are to be mixed in with the kitchen waste to achieve the right mixture. It has slats on the front for easy extraction of finished compost and a sturdy wire mesh all the way around to keep the varmints out. All in all, it is a fantastic addition to the neighborhood. But it lacks one thing: maintenance. The neighbor who built it also takes care of it. The problem is that he lives elsewhere all summer, not arriving in town until mid-fall and leaving again mid-spring. That means that all summer, when the compost should be cooking like crazy, it never gets turned and rarely gets watered. In addition, the straw, which should get added when the compost gets smelly, gets added liberally with almost every addition of compost. So in addition to not getting enough oxygen or water, it has too much brown material. It seems to me that this is a problem I can fix. Since this is a blog about engineering with biology, we will tackle this as an engineering problem.

Problem Definition

The first step is to clearly define your problem. In this case, we will define it thusly: The compost bin only gets watered in the winter, has too much brown material and never gets turned.

Parameters

The next thing you look at are the parameters of your problem. Cost is nearly always one of the parameters. For example, those 14’ long giant worms from Australia might be just the thing for this problem (but probably not), but it wouldn’t be reasonable (or legal for that matter) to import a few of them. We need to spend little to no money and use local materials as much as possible. The second parameter has already been mentioned: we will be using biological organisms to solve this problem. The third parameter is a request from the person who built the bins: “I’d rather not modify them any more than I have to; I like them the way they are.” And I agree with him.

Options

The next thing we want to consider is our options. The usual composting organisms sound like a good place to start.

Thermophilic bacteria are the biggest composters out there. They work quickly and could turn that entire pile into black gold in about two months. There is a big problem though, they need a steady supply of oxygen (usually supplied by turning the pile), lots of moisture (only available during the winter), and warm temperatures (not available during the winter).

Redworms are the second biggest composters out there. They also work quickly and would turn that pile into black gold in about 2 or 3 months, if added in sufficient quantities. If worms are added to a dry pile, they will seek moisture deeper in the soil, even if it means leaving a huge source of food behind. They are also slow to eat brown material and they tend to go dormant in the winter, retreating to the bottom of the pile and slowing down their metabolism. Now the pile is in a sunny location, so it will probably not freeze solid during the winter and it probably will thaw all the way out most days, but it will still be too cold to keep worms active.

Mushrooms are another organism that can be used in compost bins, but isn’t used frequently. The problem with mushrooms in compost is that they don’t like to be turned frequently, they prefer a mixture that is heavier on the brown material and lighter on the green material, and they are damaged by high heat. See where I am going with this? Mushrooms will work slower than bacteria or worms, but will do an excellent job of breaking down the brown material. They also have limited ability to transport things like oxygen and can continue to grow a little deeper in the pile than the aerobic bacteria. In addition, they are typically better adapted to cool conditions and can continue to grow in just about anything above freezing. In fact, many mushrooms use winter as an opportunity to get a leg up on the competition, expanding their range and collecting nutrients while the bacteria are dormant.

Choosing a Specific Material

Engineering is all about specifics. Saying mushrooms will work is not good enough. You need to select a mushroom. As I mentioned, cost is certainly an issue, so I will work with the mushrooms I already have access to and see if any of those will be acceptable.

It turns out that I have access to four different kinds of mushrooms: 3 that I am growing and one that I harvested wild from nearby recently.

The first candidate is the elm oyster mushroom (Hypsizygus ulmarius) which I am cultivating on a couple of logs. It might be a suitable mushroom, but neither log has fruited recently, so I have no access to stem butts to make spawn.

The second candidate is the black poplar mushroom (Agrocybe aegerita), which I am also growing on logs and fruited recently. I am attempting to propagate this mushroom currently. However, this mushroom has proven difficult for me to grow. It is a primary decomposer, so it prefers raw wood (not so available in the compost bin) and it has had some difficulty with my dry Arizona climate. I don’t think this is a suitable candidate.

The third candidate is the pearl oyster mushroom (Pleurotus ostreatus). I also have this growing on logs, and it also fruited recently. The pearl oyster mushroom is a primary decomposer, but it is also an aggressive decomposer of all things that used to be plants. It grows well on paper, straw, cloth, wood chips, and much more, including compost. It would rapidly decompose much of the compost, but wouldn’t break it down very far. It would also die out when it ran out of nutrients.

The fourth candidate is the shaggy mane mushroom (Coprinus comatus) I recently found a fresh wild fruiting of this mushroom and harvested both dried mushrooms (they dry quickly in our dry air) and stem butts, which I am currently trying to grow on cardboard. Shaggy manes are tertiary decomposers, meaning they live in dirt. They are also great restorers of disturbed land. They are adapted to decompose anything from sawdust and straw to manure and yes, they do well in compost. They will probably work more slowly on the compost than the oyster mushrooms, but they have the added benefit that they are native to this area. They are also a great addition to garden soil and would get added to the soil with the compost.

At this point, I am trying to decide between the oyster mushrooms and the shaggy mane mushrooms. I think that a sequencing of both mushrooms would probably be best in the long run, with oyster mushrooms added first, followed by shaggy manes a month or two later.. Also, adding worms in the spring would help the compost finish quickly, especially if the mushrooms have pre-digested much of the compost.

Over the next month, I will be propagating and expanding the mushrooms I have before putting them in the compost bin. I will be posting several articles on the different propagation methods I use for the mushrooms. I will also keep you all up to date on further details of my compost remediation project. Also, sometime in January I will be teaching an informal class on how to propagate mushrooms, using the mushrooms I have, so if you live in the Prescott, Arizona area and are interested, let me know.