Composting and Compost Crops
Composting
Composting is a foundational practice for gardeners and so many issues are improved by compost. It's a great way to process waste from the kitchen or garden, and for managing manure. It is a culture plate for growing all the soil organisms that drive nutrient cycles, and a sponge for absorbing and holding water in the soil. And it can be a great fertilizer for crops or used as mulch and overall soil conditioner.
I won't go into composting instruction; there are excellent resources already out there, including many gardening books, web sites and extension agency resources. However I will comment on what has worked for me and my observations. Composting has a special role in biointensive growing as well as in ecological gardening.
Carbon and organic matter
Compost Crops
Biointensive growing is exactly that, intensive biology. It works only due to intensive fertility management. For a closed-loop system that doesn't require fertilizers, compost is a critical and renewable resource. For this reason, biointensive growing includes growing compost materials as a major crop, a third to half of what you grow. It may seem crazy to grow food by growing compost materials, but it fuels the system and nourishes the food crops.
Using the Compost Crop
If you have ever composted, it's likely that you ran out of "green" or "brown" materials or both. Making enough compost relies on having the ingredients to build the pile. Compost crops are harvested as either brown or green materials, depending on the need and the season. When my spring compost crops are spilling over with green tops, I harvest that for the green material. Other times, I leave the crop to go mature and dry out, making it a good brown material. All this stuff can help build much bigger piles that are more likely to work hard.
Composting and Compost Crops
Using Compost in General
Often, folks think of compost as the way to build soil organic matter. But it isn't actually very good at that. It's very hard to add enough compost to make a measureable increase in organic matter.
But compost is worth its weight in gold for delivering biology to the garden. To provide the best biology and fertility to the garden, compost should be of high quality. This means active, fully broken down, with a good smell and dark color. It is hard to make good compost without moisture, so water should be added periodically.
I use compost every time I do anything to a bed, just a half inch or what every I have. I also use as a general fertilizer for repotting plants and side dressing vegetables. I soak some compost in water to water things that could use the nutrient/organism drink. When my compost doesn't look high quality, I can still mulch with it or recycle back into the next compost pile.
Determining Compost Quality
Not all composts are created equal. The best composts for innoculation and fertilizer have little to no original material in them, and have a pleasant smell and hand feel to them. They are dark and loose, and you may see filaments of fungi, insects or other evidence of the life. These qualities are a good sign that you have high quality compost.
A microscope or lab test can give you a much better picture of the compost quality. The best composts have many different types of microorganisms in them. Bacteria are soaking up nutrients, and fungi strands, protozoa and beneficial nematodes are consuming bacteria and releasing those nutrients. Good composts tests will scan for microbes and their overall activity, as well as assess nutrients. It is not necessary to have these tests done to make good compost, though they are helpful. If you have access to a microscope, you can take a look yourself.
Carbon and organic matter
Carbon in the Garden
We have a strange relationship with carbon. We clean it up and remove from the garden and even pay someone to do it. Then we go buy bags of it to use in the garden the next season. How crazy is that?
Closing the loop means having a different relationship with carbon. What seems like too much in the fall is really the compost and mulch supply we need. We should be grateful for all the free material. It may need cut up a little, but it can be added to compost, used as mulch or just piled at garden's edge for beneficial insects to shelter in.
I am diligent about chopping up my woody materials and recycling their carbon in the garden. For large twigs and pieces, I pile them up and periodically water them. Though they don't break down very fast, the soil beneath them is full of fungi. When I move the piles, small pieces remain and keep the fungi going. I stack the largest branches against the outside wall.
Using compost
My Compost
My compost is a casual affair. I make piles all over the garden as material becomes available. We are water challenged in the desert, and the compost must stay moist. I often cover my compost pile with something to protect the pile from the sun and hold the water in. An effective trick I've started using is to wet a bucket or tub of leaves ahead of time and add to the pile.
I rarely have enough material to hot compost, so I cold compost. I have more space to grow my garden, so building lots of compost is a top priority for me this year. For this reason, I've been growing lots of compost crops. I know their roots are breaking up hard soils and feeding the ecology underground by leaking sugars and nutrients as they grow. That soil community will cycle and share nutrients with my food crop later on.
I use sheet mulching as often as I can. It is basically composting in the bed itself. Another similar method is the "Lasagna Garden" method. I alternate deep layers of compost materials and layers of brown materials with cardboard or newspaper sandwiching it all in. I aim for 1ft of mulch layers, watering between every layer and periodically for 4-6 months. Then I can start growing vegetables in the resulting composted bed.