Composting with Chickens

Chicken compost structure

I love an elegant design. But what is an elegant design? Elegant is defined as pleasingly ingenious and simple. From an engineering standpoint, an elegant design is typically a design that achieves multiple functions through simplicity rather than complexity. This is easily accomplished with biological systems with just a little thought. Think about the process happening. Is there work you are doing that something else would happily do for you? Are there organisms that could be inserted into the process that would provide benefit without any real loss?

While I have tried to achieve this with my living systems since I was a teenager, one of the best examples I found was from Paul Stamets. He explained that if you compost wood chips, you can get compost, albeit slowly. If you grow mushrooms on the wood chips first, you get mushrooms. Then the spent mushroom blocks can be composted to still get compost, and faster. The addition of the right organism in the middle of the process makes all the difference.

Such is the way with chickens and compost. Chickens are omnivores. Their natural diet is a mixture of plants and bugs, with a healthy mixture of seeds thrown in. Commercial chicken feeds are mostly grain based. They give the chickens the basic nutritional needs, but don't really give them anything extra. Allowing the chickens to process compost on the other hand, is a natural fit that achieves multiple functions.

Chicken compost structure from the inside

For our purposes, we took an existing structure that was built for compost. It was constructed out of PVC pipe and wire and measured 11' by 14' and tall enough to stand comfortably in. We moved it into a corner that was out of the way and put an existing chicken coop inside. The coop gave the chickens a place to roost and lay and gave them protection from the rain and sun. Then we built four compost bins, one cubic yard each, using the same PVC pipe and wire techniques. The doors on the front of the bins rotate down. Then, since this is Phoenix and it is hot here, I installed a mister system over the compost bins to keep the compost wet and the chickens comfortable in the summer. 

To feed the chickens, I toss compost out into the open area. I also wander around and harvest a big bucket of weeds daily for the chickens to eat. Grain is given supplementally as needed and just to make sure they have enough food. The chickens pick through the weeds and kitchen scraps and eat what they want. The rest becomes litter under their feet and they manure on it. When the litter layer builds up enough, we scoop it up and toss it in one of the bins. Then we spread out a starter layer of straw or drier weeds and start the process over again. I hope to use wood chips soon as well. 

Once the compost is in the bins, it heats up to hot compost range within a few days. Once a week, we drop the front gate to the bin, and spread the compost out a little. The chickens dive right in and hunt for bugs. After a day or so, we scoop it up, water it a little, and mound it back up in a different bin. The process produces compost remarkably rapidly. We are actually having trouble keeping the temperature down enough on the compost bins. We don't want them so hot that they are essentially burning off the carbon we are trying to capture. 

Store bought eggs mixed with
eggs from our chickens

The best part is the change in the chickens. They have a habitat that is full of vertical relief to explore, attractive to bugs, and gives them lots of room to scratch around in. They have been much happier and engaged since moving into the compost bin. Plus, the change in the eggs has been remarkable. See, the color of the yolk is a good indicator of how healthy the chicken's diet is. Pale yellow yolks indicate a poor diet, usually of mostly grains. Darker yellow to orange means the diet is significantly improved. I hear that with attention to a great diet, the egg yolks can be almost made red. I haven't gotten there yet. 

Personally, I think that this could be done on a larger scale to take advantage of large scale food waste. Restaurants could collect food waste separately and they could be collected daily, or every few days at the least. Then the food scraps could be dumped into a chicken compost facility with several hundred chickens. They will eat what appeals to them. The remnants could be mixed with wood chips, also from municipal waste, and composted. The chickens could be brought back once a week or so to further pick through the composting material, keeping bugs down and helping it compost. At the end of the product, there is great compost produced, happy chickens, healthy eggs, and a reduction of the trash stream.

Making Humus

First I want to be clear. I am not talking about hummus, the yummy dip that comes from various cuisines around the Mediterranean. I am talking about humus (pronounced HYOO-mus). Humus is a type of soil derived from fully decomposed organic matter. It is black and rich and just about the best thing you can have for growing plants. But humus isn’t just more compost or similar. It is stable and retains itself long term in the soil.

So if it is so great for your plants, how do you get it? Well, that’s the problem. Humus is quite possibly the most valuable substance on the planet, even if nobody realizes it . Everything that supports our life on this planet, from the air we breathe, to the water we drink to the food we eat depends on humus. But nature makes it very slowly. As a kid my dad always told me that it takes nature a thousand years to make an inch of topsoil (which is mostly composed of humus). While I don’t think it takes quite that long, there is certainly not enough that it can be sustainably harvested, even on a small scale. Plus, current farming practices degrade the topsoil rapidly. Tilling in particular is very damaging to the humus.

However, we can make humus. Before we do so, there is one thing we need to understand. What is humus? Quite simply, humus is distilled from decaying organic matter. The problem is that the process of distilling the humus isn’t very efficient. You can’t take a cubic yard of fall leaves from your yard and get a cubic yard of humus. That cubic yard of leaves might give you a couple of tablespoons of finished humus. After 3 or 4 years. But it isn’t quite as bad as it sounds.

The basic formula is this:

Organic Material => Organic Matter => Humus

Organic material is just about anything that was produced by a living thing. Woody debris from plants are best. Add it to your compost bin and compost the heck out of it. The composting process removes most of the bulk that is going to go away. That cubic yard of leaves will give you a gallon or so of finished compost. Then add that to your soil. Over the next several years, that will break down further into a beautiful humus.

Now there are just three things to remember:

1) The reduction. When you realize just how much organic matter reduces to make good humus, you will join the legions of us who spend lots of time creating a huge composting operation. It really is the most important thing you can do for your garden.

2) The reason humus is so great is that it feeds the living organisms in the soil that form the ecosystem your plant is existing in. By adding compost, you are feeding the soil organisms. The fact that you are making more and more humus from the process is actually almost secondary. Feed your soil!

3) When you stop feeding your soil, the humus starts to break down and will eventually be lost. Actually, this is happening all the time anyway. It is just that regular additions of compost add humus to the soil faster than it can break down.

So go out and make more of the real black gold, the basis for our existence on this planet!

The Most Important Concept

Let’s say you discovered a concept. This isn’t even a new concept, just one new to you. And let’s say it caught your eye, changed your worldview, and occupied your thoughts for some time. And let’s say that through that thinking process you discovered that this is the most important concept that there is, that without this, life on Earth would cease to exist. Then you look around and see that despite this concept being fairly well understood in the scientific community, almost no one else understands it. And not understanding it is driving people’s actions in a way that is causing a huge amount of long term harm. What would you do? Would you harp on it quite a bit? Me too.

So what is this concept? Quite simply: Soil is a living organism.

Okay…that doesn’t seem so ground breaking. But let’s take a moment to examine this, maybe look at it from a slightly different angle that might clarify things. You are a living organism. You are composed of a tight association of smaller organisms that all have the same DNA. Each organism has a job, a purpose, to help the whole system function optimally.

Soil is composed of a tight association of smaller organisms that all have different DNA. Each organism has a job, a purpose, to help the whole system function optimally.

Let’s take the biological approach. To understand an organism, you need to understand its food source, how it acquires its food, and the role it occupies in the ecosystem it occupies. Let’s deal with those one at a time.

What is soil’s food source? Well, nothing, you might say. The different organisms eat each other. Well, yeah, sort of. But what happens to an animal when you stop giving it food. It begins consuming its own body, losing weight in the process. As it loses weight, it loses functionality, until the whole system is no longer able to function and it perishes. Our soils worldwide are doing exactly this. Soil feeds on decaying organic matter. Wood, roots, leaves, and sticks form the bulk of soil’s diet, but dead insects, rotting mushrooms, and feces provide sustenance as well.

How does soil acquire its food? In a natural ecosystem, it falls to the ground from the vegetation growing above. It doesn’t matter whether it is a forest or a grassland or something in between. Everything dies eventually and gravity delivers it to the soil to be consumed.

That little pile of mostly decomposed vegetation at the top
was living clover just one month before this picture was taken

What role does soil play in its ecosystem? Disease causing organisms aside, the organisms that evolve in an ecosystem evolve to play a role in the healthy version of that ecosystem. Soil needs decaying organic matter to survive, right? So why doesn’t it just kill all the plants and feast? That’s a lot of food in the short term and no food in the long term. So it could just keep the plants sickly and they would drop small numbers of leaves frequently and die early. That is a better long term solution, but it is a recipe for a permanent diet of not quite enough. No, anyone who has tried to maintain a landscape in their yard knows that the more plants you have and the more lush and healthy they are, the more debris they drop to the soil surface. So soil has a vested interest in keeping the plants lush and healthy and growing as fast as possible. How do they do this? They break down the nutrients in the decaying organic matter and feed them back to the plants so they have what they need to grow more.

Just how poorly is this concept understood? In 1975, Masanobu Fukoka wrote The One Straw Revolution. The book chronicles his decades long quest to get academia to understand the concept that the organic matter needs to be returned to the soil. We still aren’t there. In fact, I recently found this great video from a soil scientist at the Soil Conservation Service trying to convince farmers that soil is alive and needs to be treated as such. We are just not getting it.

 

And as we starve our soils, they become emaciated and unable to do their job, so we dump fertilizers on them, hoping that the chemicals will make up the difference. But it can’t really. Living soil does so much more than just hand out nutrients. It stores massive amounts of carbon in its body (finished humus, the final form of organic matter in soil is over 50% carbon), it serves as a sponge to soak up rainwater and reduce runoff and erosion. It works with the plants to increase resiliency and reduce the impact of diseases. As we let our soils waste away and die, our fields lose productivity, and right at a crucial time when we are trying to figure out how to feed a lot more mouths.

So remember, take care of your soil and feed it with lots and lots of decaying organic matter. Our lives all depend on it.

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. 

Harnessing the Power of Living Soil

A king stropharia mushroom growing among the carrots
in my garden system.

Viewing the world as an engineer, as I do, I tend to look at revelations and discoveries from the viewpoint of how they can be utilized to help solve real problems. Living soil is no exception. As I mentioned in my last post, living soil is excellent at balancing the chemistry and managing nutrient loads. But what can this insight be used for? How can it be used to make our lives better? A couple of years ago, I decided to combine aquaponic system design with the power of living soil. The success of the system has been a little surprising to me, even with my high hopes. The soil has proven to be very adept at balancing an aquatic system as well as its own and doing a great job of processing and retaining nutrients for the plants. Allow me to share two stories of things I have observed my system doing:

Story 1

Garden System Version 1.0

When I first built my system, I used a small aquaponics system with hydroton (expanded clay pellets) media and a 55 gallon sump tank. This was outside in June in Phoenix, Arizona, and the temperature was hot. I had to add about ten to twenty gallons of water a day to keep the levels up. Unfortunately, as water is lost in the system, the minerals are conserved. Tap water in my area comes out of the tap with a pH of 8.0. After a few weeks of concentration, my water was hovering around a pH of 8.6. At that range, the fish aren’t happy and the plants lose their ability to absorb a number of nutrients. I kept adding various acids in an attempt to get the pH down, but the fish didn’t like that process either and it never stayed down for more than a few days before I was adding more.

Finally, I managed to scrape together enough money and time to build my large garden bed. It is 4 feet by 8 feet and I filled it with a mixture of coconut fiber, wood (mostly spent mushroom logs), perlite, and compost. Then I added a generous number of worms before planting it. Immediately the soil sprung to life and began doing what soil is supposed to do. Within a matter of days the water dropped to a pH of 7.0. Over the next several months of intense heat and intense water loss and mineral concentration, it balanced out and eventually reached equilibrium at a pH of 7.6. This is actually a pretty good level for both the fish and the plants and it held that pH for almost a year without any assistance. The living soil in the garden, with plenty to eat, did its job and balanced the chemistry of the whole system, water included.

Story 2

My poor, sickly basil

Last spring, as the plants grew, I started noticing a nutrient deficiency. While most of the plants were clearly suffering from it, it was obvious that certain plants, like squash and basil, had it the worst. As new leaves grew, they would come out white, completely devoid of the necessary chlorophyll. I looked up the nutrient deficiency on my charts, as each deficiency has its own symptoms, and discovered it was definitely an iron deficiency and possibly a magnesium deficiency on top of that. So I added some chelated iron to fix the iron issue and some Epsom salts to fix the magnesium problem. I added a tablespoon or so of each every 2-3 weeks. After about a month of treatment, the white leaves stopped appearing and the plants resumed vigorous growth.

I continued the treatments for a month or so after the plants recovered, just to make sure they were going to be okay, and then I stopped adding the supplements. Not long after that, the weather warmed up. I had some nearby plants that were in containers, but outside my closed system. Rather than try to remember to water them twice a day, I hooked up a side line. Every time my system watered itself, a drip line also watered the container plants from the fish tank. An added benefit of this was that it prevented the buildup of mineral salts in my tank water. However, it also meant that all those great dissolved nutrients in the water were also lost. Now, more than six months have passed and there have been no return of the symptoms of nutrient deficiency. Since the soil is all the same but the water is all different, that means that the living soil snatched up all the nutrients it could get while they were plentiful and have been feeding them to the plants as needed.

I really think that the utility of living soil is one that is worth exploring further and including in more and more projects.

Soil as a Living Organism

Sometimes, looking at something commonplace with new eyes, new perspective, and new insight can be one of the hardest things there is to do. And sometimes there is nothing more important to do. What can be more commonplace than soil? We walk over it every day. Yet to dismiss its importance, its power, is to miss a great deal. Sylvia Bernstein, in her book Aquaponic Gardening, printed a quote from Kobus Jooste from South Africa that attempted to strip down soil into its constituents, ending in the following conclusion: “UBERFACT: Soil is an anchoring medium to plants that may or may not, over time, release some of the stuff plants need to grow.” I nearly stopped reading the book at that line, but powered on for the other wisdom the book has to offer. Still, that sentence comes back to me often. Rarely have people been more wrong.

The first thing to realize when looking at soil with new eyes is that soil is a living thing. True, it is not a single organism, but rather a complex media filled with tens of thousands of different organisms. But the organisms work so well together that they can almost be treated as one organism.  So, when a biologist studies an organism, what are the first couple of things they look for? Two of the most important aspects in understanding an organism are what it eats, and what role it fills in the ecosystem.

First let’s tackle the food source for soil. Yes, soil needs to be fed. Like any other living organism, soil breathes air, drinks water, and consumes a food source. In the absence of any of those, the soil will fail and die. As for what soil eats, it is really simple. It eats whatever organic matter falls to the soil surface. From there, through a series of digestive processes of different organisms, the particles of decaying organic matter get broken down into smaller and smaller pieces, the larger organic molecules digested into smaller ones. Mass is lost as carbon from cellulose and lignin and a host of other molecules are slowly turned into carbon dioxide. But the process is so much more complex. The cellulose and lignin were locked in what used to be the body of a plant, a plant that had metabolic processes and scent and its own DNA. All of those complex molecules that created the things that made the plant alive came with their own chemical signature. As they break down, the carbon is lost to the air, as is some of the nitrogen. However, the phosphorus and potassium and calcium and iron stay behind. They get recombined and further broken down by that wonderful process of decomposition and soil creation. What they finally create is exactly what the plants need to take up and start all over again.

The pile of mostly decomposed plants in the background
was living white clover two months earlier. The heat of
summer killed them and the soil gobbled up the readily
available food source.

 As an engineer, understanding soil isn’t just enough. What does it DO? What can I use it for? In order to tackle that question, I need to answer the other question: what role does soil play in its ecosystem? You probably learned in grade school science class, as I did, that soil provides nutrition and structure for plants. While this is true, it is a tiny portion of what is really going on. Soil plays an incredibly important role in the ecosystem. To work that out, let’s look again at soil’s food source. It needs decaying plant matter to feed on. Where does it get decaying plant matter? Well, it first needs healthy plants to grow, so they can drop leaves and eventually die. What produces more decaying plant matter, a lush growth of plants, or a few spindly plants that are already dying? Anyone with a lush landscape in their yard can tell you the answer to that one. The more plants there are, the more waste they drop.

So now we know that the soil organisms have a vested interest in growing a lush stand of plants. How do they do this? Again, we will answer a question with a new question. What is the biggest problem facing the plants? Plants need sun, water, air, and a good source of all the minerals and micronutrients they need to grow. The first three are outside the control of the soil organisms, but the last is fully within their control. There are two primary sources for the nutrients the plants need: decaying plant and animal material and the minerals in the soil around them. The soil needs to be effective at releasing those nutrients from both sources and getting them to the plants.

That brings up the next problem. How does the soil retain the nutrients long enough for the plants to get them? Have you ever performed a soil test? You put soil in a jar with water and shake it really well, then test the water for nitrogen, phosphorus, and potassium. Why is that? Well, the shaking is because the soil is working really hard to hold onto those nutrients. You test the water and not the soil because those nutrients are soluble in water. The soil has to find a way to lock those nutrients in, and where they fail, filter them back out of the water before they are lost to the water cycle.

It turns out that soil is remarkably good at doing just that. The bacteria produce polysaccharide glues that hold soil particles together. Fungal strands also serve to bind soil particles together. Fungal networks are shaped like a tight net, and have proven to be very good at filtering water.

There is another function of soil that is often overlooked. There is an old gardening addage: If you want to raise the pH of your soil, add compost. If you want to lower the pH of your soil, add compost. Plants are only able to absorb nutrients within a certain pH range. The problem is, different compounds work best at different ranges. Since the organisms in the soil have a vested interest in getting those nutrients into the plants, they also want to make sure the plants can absorb the nutrients. So they also take on the task of balancing the soil chemistry.

Naturally, all this is a gross oversimplification, but it has to be. There have been volumes written on tiny portions of this process. There are whole fields of science that study nothing but soil chemistry and biology. But when you think of the problems you have, think of what soil needs to do and how a healthy, living soil can help you and your plants. Then go out and feed your soil.

Testing the Soil

As I have mentioned here before, I currently garden in containers. One of the challenges of container gardening is that the reservoir of available nutrients is much smaller than it is in the ground. If you have mycorrhizal fungus in your in-ground garden, it will search out far and wide for available nutrients to gather for your plants. In a container, the plants and mycorrhizae alike are limited to what is in the container’s soil.

When I made the soil, I used good quality compost. As the plants were growing, I added good fertilizer. I specifically looked for fertilizer that had rock phosphate and greensand. Both are hard to find, but both are rock-based sources of potassium and phosphorus. They should have good lasting power in the soil. There is no such thing as a rock-based source of nitrogen, though, so I had to look for other solutions. Last summer, when I was fertilizing the soil, I made extra care to add blood meal in addition to the general purpose fertilizer. Blood meal is a great source of nitrogen, even though it doesn’t necessarily have much lasting power in the soil.

Last fall I began noticing a little slower growth in my plants. This spring, it almost slowed to a crawl. My seedlings were slow to sprout, slow to come up, and glacial in their growth. All but the peas, that is. Peas, along with the bacteria they culture on their roots, have the ability to fix atmospheric nitrogen on their own. It seemed a sure sign that my soil was lacking something, probably nitrogen. It was time to break out the soil test kit.

I got a Rapitest kit that tests for pH, nitrogen, phosphorus, and potassium. Testing each pot for all 4 numbers took a while, but it was well worth it for the information gained. For those of you who haven’t used chemical soil tests, the use is pretty easy, and not too time consuming. You dig down about 3-4 inches in your soil and get about a cup of soil, sometimes mixing from a couple of different places if you are testing a larger area. Then you mix the soil with distilled water (I used filtered, which might have thrown off my results a little, but not much.) per the package directions and shake really, really well. Then you let the soil settle out, which usually takes 10-30 minutes unless you have clay soil, which might take a couple of hours. Then you dump the powder for the test you are about to perform into the provided vial and fill to the line with your test water. Shake for a few seconds and then let it sit for about 30 seconds. Then you just compare to the colors on the vial to see how much of each nutrient you have.

As expected, every single one of my containers tested as depleted or nearly depleted in nitrogen. Oddly enough, though, each one had more than adequate, even excessive, amounts of phosphorus and potassium. They also tested in the general range of neutral in pH. A couple were slightly alkaline and a couple were slightly acidic, but all were pretty close to neutral.

Now all I need to do is get some nitrogen in there so my plants can grow with wild abandon!

Hugelkultur

I have grown many mushroom logs over the years and, like any good composter, hate to throw them away when they are spent. It is still a good source of carbon and minerals and not to be wasted. I usually chop them up roughly and throw them in the compost bin, where they tumble for some time, very slowly getting smaller. When I redo one of the containers in my garden, I find I am often short on soil (due in large part to my dislike of store-bought potting soil), so I throw a chunk or two of the decomposing log into the bottom of the pot to fill space. I figure the log will slowly decompose over several years time. During that time, it will feed the soil and provide a reservoir of nutrients.

Recently, I came upon a method of soil-building called hugelkultur. The basic premise is that decaying wood harbors a great diversity of life. If you see a fallen log in the forest, it is covered with different organisms. The older the wood, the more life there is. So, according to hugelkultur, when building soil, you bury wood in the soil. The wood provides both shelter and food source for a wide variety of life. Over the course of several years, the wood will break down into a rich soil that is full of organic matter and many nutrients.

When a mushroom log is good and spent, the interior is spongy and soft. They are easily chopped up into smaller chunks with a large knife. When putting together a new pot full of soil, I like to put a layer of well-draining material on the bottom, like sand or rocks, and then a layer of roughly chopped spent mushroom logs on top of that. I mix it in well with some good compost and then make sure I have three to six inches of dirt on top of the wood. This gives new plants plenty of room to spread their roots without running into wood immediately. While a plant can push its roots through mostly rotted wood, it may have difficulty with some of the harder portions or if you use fresher wood.

Thus far, I have only found two difficulties with hugelkultur. The first is that rotting wood is low in nitrogen. This means that your soil will most likely be low in nitrogen, too, so other sources, such as blood meal, compost, and nitrogen-fixing plants are a good idea as your soil matures, especially if you are going to be growing plants that need lots of nitrogen, like fruits and vegetables.

The second problem is that wood is high in carbon, which mostly gets converted to carbon dioxide as it decomposes. This is good for your plants, providing a slow, steady supply right where they need it. However, that carbon all takes up space. This means that the level of your soil will slowly drop as time passes, sometimes by several inches. This is great for annual plants, as it gives you lots of room to add compost. However, it can be bad for perennials as they slowly get buried in the compost you have to add.

Overall, though, I really like it as a method for bulking up soil in a new bed or container. I especially recommend it for mushroom growers, like me, who have lots of spent logs laying around that they don’t want to throw away.

Raised Bed Garden or Sunken Bed Garden

When starting a garden, the goal is to maximize your advantages while minimizing your disadvantages. A raised bed garden is a good way to do this. By building a raised bed, you give your garden great drainage. You don't have to worry about poor native soil, either. You need to fill up the raised bed anyway, so you might as well fill it with the good stuff. A raised bed garden also helps bad backs by making it so that you don't have to bend over so far to get to your garden. In addition, there are other minor benefits, such as getting the garden up high enough that certain pests, like rabbits, can't get to it. If slugs are a problem in your area, a simple strip of copper ringing the raised bed will keep them out. Slugs and snails won't cross copper.

When I started my first garden at my first house here in Arizona, my goal was to create a raised bed. Materials were expensive and I didn't have a lot of money, so it was a long term goal. But after a few years, I discovered that a raised bed garden would not necessarily be a good thing here. In the arid southwest, good drainage is a bad thing. The more water you let drain away, the more you have to supply. All of our water here comes from the ground. The more you use, the more you pump out. The more you pump out, the less there is to go around. So conserving the water you have is a very good idea. In addition, we get close to enough rain to water everything. It just doesn't always come down when you need it. So the real way to make that work is to store as much water as you can when it does come and use it for the dry periods. A rain barrel makes for a good storage device, but it can become cost-prohibitive to buy enough to fully meet your needs. What you really need is a way to keep the water that hits your garden, a way to store the water in the ground.

A sunken bed garden does just that. It keeps the water from flowing away long enough that it can soak in. You then have the water stored in the soil itself, which will help the plants last longer between waterings, which means less water used overall. If your terrain allows, you can even shape the earth so that your sunken bed catches runoff from elsewhere. I will cover methods for doing that in a future post.

Another advantage for sunken bed gardening here lies in the soil itself. There isn't as much sand in Arizona as you might think. In fact, there is a lot of clay, and lots of that is expansive. Expansive clay works much like water-grabber crystals. When they are exposed to water, the microscopic particles expand and hold on to the water. In its natural state, this is a bad thing, and not just for your building foundations. During a rain event, the clay particles on the surface swell and seal off the pores in the soil. This means that the water can't really penetrate deep into the soil and just runs off, wasted. A sunken bed will help the water sit long enough for it to soak in. It still may just sink in a few inches, just enough to saturate the surface and cause troubles for the plants that don't like wet feet. To really take advantage of the water-holding properties of the soil, you need to amend the soil. When you first create the garden dig down a foot or more and amend with organic material, preferably composted wood chips. The wood will have some lasting power in the soil. Ideally you'll have as much as 50% of the volume of the soil as organic material. This will open up the pores of the clay and let the water soak in deep. The clay particles will still swell and hold the water, but now more of them can do the work, delivering it slower and holding it over a greater area. Also, if you treat the soil with a mycorrhizal fungus, the fungus will travel through the organic material, better surviving than in a soil that is poor in organic material. It will then send its filaments throughout the soil and grab the moisture that the plants can't reach and deliver it to the plants.

So, how do you design one of these? I'll cover that in a future post as well, so stay tuned. For now I'll just say that factors like local rainfall, soil and what you are planting all come into play. I will also say that this sort of design is ideally suited for landscaping and will give you a lower-maintenance landscape. It is a little trickier for vegetable gardening.

Living Soil

Most gardeners see their job as one of taking care of the plants. You water them when they get dry, fertilize them as needed and deal with pests and diseases. But how does this process work in nature? Nature takes care of the plants. So why doesn't it take care of the plants in our garden? Nobody fertilizes that beautiful meadow you hike through on your weekend hike, so how does it look so lush? Nobody sprays it for fungal diseases and pests, so why do the plants there only have minimal damage despite a lack of intervention?

Despite what we like to tell ourselves, a garden is a very un-natural place. Nature is subverted at every turn. A fully natural garden would look like a meadow and the Home Owners' Association would show up and cite us for not removing weeds.

So what is it about those natural environments that nurtures the plants and keeps them healthy so effortlessly, and more importantly, how can we mimic that environment without invoking the ire of the neighbors? The key is living soil. Soil is not just some foundation beneath our feet, a stable medium for plants and a source of important minerals. It is very much alive, or at least it should be. Soil is it own ecosystem, it just exists on a microscopic scale. It is filled with bacteria, fungus, insects, worms and much more, all living in harmony. Each player has a niche to fill, a job to do, and is an important part of the whole. Nearly half of each plant exists immersed in this ecosystem and has evolved specifically to live in that environment.

Healthy soil nourishes the plant and increases its health. Healthy plants don't need outside intervention to prevent pests and diseases. They have an immune system, just like you and I. Plants grown in healthy soil are healthy and have the ability to fight disease. They also grow faster, get bigger and are able to produce more sugars.

So how do you make healthy, alive soil? As always, we take our cues from nature. What soil amendments does nature add? Dead plants and insects are returned to the soil to decompose and occasional doses of manure are added. That's pretty much it. It needs regular doses of organic material.

But dead plants laying all over the ground is unsightly. How do we fix that? Well, that’s where bioneering comes in. Compost is bioneered soil. By composting our organic material, we create the ideal soil ammendment, the perfect food for our living soil. Also, regular applications of organic mulch, such as wood chips and straw help a great deal. Those ammendments feed the soil, which in turn cares for our plants.

So remember to feed your soil!

Oh, and synthetic fertilizers are like junk food for your soil. It doesn’t create lasting health, especially if you don’t also give it the healthy food.