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!

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.

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!

Epiphytes

When I first started growing plants as a teenager, I quickly grew tired of the plain, old, boring plants that everyone else grew. I have never had a spider plant and never plan to grow one. As I learned more about different types of plants, certain types quickly rose to the top of my favorites list. The first was carnivorous plants. Succulents then became a favorite. But really, one of my longest running loves is with epiphytes.

“Epiphyte” is another word for “air plant.” They are a class of plants that grow up in trees, often with little to no contact to the soil below the tree. They are also not parasitic to the tree they live on, getting their nutrients from the air itself or what little else they can find on the branch, such as bird droppings. Epiphytes are common to tropical environments and somewhat less so in subtropical environments. While some kinds of epiphytes, such as tillandsias (which are a subgroup of bromeliads), are capable of surviving with literally no soil, most require a little. In the wild, plants firmly anchored to tree limbs attract debris and droppings, which break down into a sort of soil that collects on tree limbs. In fact, some of this soil has been found to be fertile enough that the trees grow roots out of their limbs to take advantage of the nutrients. However, the “soil” is always thin and light and drains well.

In cultivation, most epiphytes are grown wired or glued to a log or piece of bark with a little sphagnum moss packed around their roots. Some are grown in pots, but the soil is often loose and well-draining. Orchid bark is a good example of soil that is specifically designed for epiphytes, as most orchids are epiphytes. As for watering, a light mist two to four times a week will do for most species and nearly all prefer to dry out between waterings. Despite growing in wet climates, their soil is so thin that they are more adapted to dry conditions than many of their neighbors. Also many do not require any fertilizer at all. Many also prefer dappled light since they tend to have a canopy over their heads in the wild. All of these things make many epiphytes great houseplants and there are many varieties available. Below are some of the different types of epiphytes out there.

Orchids

Most orchids (with the notable exception of Paphiopedilums) are epiphytes. I had a Phalaenopsis and an Encyclia that I grew epiphytically on a log in a dry climate for over a year. While both survived, neither flowered, probably due to the fact that I rarely fertilized them and watered them all too infrequently. Some orchids do better than others in that sort of situation, but most will die if planted in soil. Plus, the amazing blooms of these plants make them worth a try.

Bromeliads

Bromeliads are probably the most famous of the air plants. While there are terrestrial bromeliads (pineapple is one), many are very epiphytic. I have three different Tillandsias that have been living without so much as a little sphagnum moss around their roots for over 4 years now. I suspect that if I was in a humid climate, I probably wouldn’t even have to spray them. If you look a little deeper than your local grocery store, you can find some bromeliads with really fascinating foliage. With proper care, they flower every 2 years or so, producing blooms that rival orchids. As a bonus, when the blooms fade, the parent plant produces pups, which are miniature plants. When those get to about half the size of the parent plant, they can be removed and planted elsewhere.

Cactus

There are actually several varieties of vining, epiphytic cacti. Their adaptation to dry climates must have made this a natural move. I can only imagine that a dry-adapted plant moving into a moist environment would cause them to evolve to take advantage of the driest microclimate available. I am just starting to grow my first epiphytic cactus, but they are still just seedlings. I’ll talk more about that in my next post.

Nepenthes

Nepenthes are commonly called “tropical pitcher plants.” They are a family of plants that start on the forest floor and then climb up the nearest tree. As with many tropical plants, they have a drip tip on the end of their leaves. Only in Nepenthes, the dip tip has become highly evolved. As the plant gets bigger and feels the lack of nutrients in its chosen home, the drip tip enlarges into a little pitcher that is used to capture and digest prey, thereby giving the plant the nutrients that growing on a tree lacks. The pitchers of nepenthes tend to be more elaborate than terrestrial pitcher plants and quite beautiful. In fact, some of the largest pitchers in the world belong to Nepenthes. Nepenthes rajah is reported to have pitchers big enough to capture a rat.

Ferns

There are a couple of kinds of epiphytic ferns. The white rabbit foot fern has white, fuzzy aerial roots that sort of look like rabbits’ feet. However, by far the most fascinating of the epiphytic ferns are the staghorn ferns. A staghorn fern starts on the side of a tree and grows two kinds of fronds. The basal fronds grow short and round and cover the root ball, protecting and enlarging it over time. The fertile fronds are what the plant is named for. They grow long and wide and sort of resemble the antlers of a moose. Mature staghorn ferns can be several feet across and are absolutely majestic plants. Thus far my attempts to grow any epiphytic ferns have been unsuccessful as they don’t tolerate the lack of humidity in my climate.

Ant Plants

While I have never grown an ant plant, and probably never will, I still find them fascinating. In addition to the usual complement of leaves, ant plants grow an enlarged, bulbous base that is riddled with tunnels. In the wild, ants move in and inhabit the tunnels, allowing the plant to take advantage of their waste.

If you are interested in possibly growing any of these epiphytes, I strongly recommend giving Black Jungle Terrarium Supply a visit. They specialize in supplies for making terrariums for poison dart frogs and have an amazing variety of epiphytic plants.

Geeky Gardening

I have mentioned several times in this blog that I am a total biology geek and that gardening is my expression of those tendencies. But this definition bothers me. My wife and I are proud geeks, but is gardening really geeky? I mean, it is usually done outdoors. There's sun out there! Geeks aren't usually known for their deep tans.

However, there are certain aspects of gardening that are intensely geeky. As John Hodgman said, "We are geeks. We are defined by our passions and our enthusiasms." There are few pastimes that inspire passion and enthusiasm in so many people as gardening. Gardening can make normal people talk about, and even research, things like chemistry, botany, zoology, microbiology and even mycology. It can make a seemingly normal person keep a thousand red worms as pets, fussing over their enclosure, their health and the quality of their bowel movements. I typically observe the status of my gardens at least 4 times a day. And yes, I can tell the difference, thank you. If that doesn't qualify as passion and enthusiasm, I don't know what does. So if you think that the statement "Can't see the forest for the trees" should be revised to say "Can't see the forest for those yellow spots on the leaves. Dammit! What is that, blight? I am going to have check my gardening books and spray now..." then perhaps you should check your habits against the list below. It might just give you some ideas.

1) Garden Schedule
Gardener: Knows when first and last frost dates are and plants accordingly.
Geeky Gardener: Knows exact planting dates of all seeds relative to first and last frost and keeps records.
Über Geeky Gardener: Enters all of those dates into a calendar program with a "repeat yearly" option.

2) Soil Chemistry
Gardener: Understands that there are nutrients in the soil that are essential to the growth of plants and adds fertilizer to make sure there are enough of each.
Geeky Gardener: Owns a soil test kit and several electronic gadgets and knows the exact soil composition in any given location because he tests it regularly.
Über Geeky Gardener: Created a raised bed garden and made all of his own soil so he could have exact control.

3) Tools
Gardener: Has a set of tools that he keeps in good working order.
Geeky Gardener: Has all the best tools and they are kept razor sharp, well oiled, and hung on pegboard, complete with outlined shapes so the unkempt masses don't put the tools where they don't belong.
Über Geeky Gardener: “What, they don't make WiFi moisture meters and networked programmable automatic watering systems? I guess I'll have to make my own...”

4) Latin Names
Gardener: What's a Latin name?
Geeky Gardener: Knows Latin names and family groups for most of his plants.
Über Geeky Gardener: Knows exact Latin name, including genus and species, of every plant is his garden, including cultivar names and refuses to call them by anything else.

5) Weather
Gardener: Understands basics of seasons in his area.
Geeky Gardener: Has a weather station and records rainfall and temperature highs and lows.
Über Geeky Gardener: Maintains a weather station for NOAA.

6) Garden Planning
Gardener: Knows where they planted each plant.
Geeky Gardener: Will painstakingly plan out their garden, developing diagrams (probably in AutoCAD) of what was planted where and keep them for posterity to help with crop rotation.
Über Geeky Gardener: Will plan it all out, just like the geeky gardener, but will also take companion plants, beneficial insect habitats, sun angles, plant light requirements, soil that has been previously innoculated for legumes and light exposure into consideration. He will also specially plan out and design microclimates for his perennials and slow-growing annuals.

7) Garden Biology
Gardener: Understands that the different organisms in the garden interact and that those interactions are important.
Geeky Gardener: Seeks to understand as many organisms as possible and to control garden health through the use of careful applications of organic matter, organic fertilizer, companion plants, beneficial insects and more.
Über Geeky Gardener: Does all the same things as the geeky gardener and then blogs about it.