If you missed the last article on composting, please find it here. It briefly explains the concept from a beginner’s perspective. This is the second article in the series, explaining the relationship of ingredients used to create the excellent soil amendment called compost.
to understand the different ingredients in compost;
explain the process;
understand moving and turning compost;
examine the chemicals in compost;
explore improvements and potential problems.
The different ingredients in compost can include anything that grew out of the ground. Recognizing this important goal of composting was the main goal in the last article. Now to identify the different parts of compost. The summary of this article can be stated already: the bigger the pile, and the more it includes, the better the compost!
Compost can be identified by two major groups of ingredients, plus a third group that adds trace minerals. The groups are the high carbon materials called “browns,” and the high nitrogen materials called “greens.” The third group is either browns or greens that have been burned before composting. They are called “grays.” Grays do not make compost. They fertilize the compost with rich deposits of minerals that the plants, bacteria, and fungi can use.
Browns are called that because most of the browns in compost are brown! Wood and woody stems, twigs, cardboard, dry leaves, and brush are all browns. Likewise, greens are mostly green! Grass, weeds, fresh leaves, most vines, annual plants, and kitchen scraps are mostly greens. The important part of the browns and greens, however, is what they are made of. Browns are full of carbon. Greens are full of nitrogen. Both are important in making compost. The best balance for good compost and a rapidly composting pile is to mix half browns and half greens.
We turn or “stir” the compost to mix the ingredients with the bacteria. When started, the browns and greens tend to be concentrated in different areas, so bacteria flourish in small clumps. Mixing up the materials and the bacteria at regular intervals provides new material to the big clusters of bacteria, and it divides the bacteria to new areas of food.
The process of composting is all accomplished by bacteria, fungi, insects and small animals. If the compost is in good order, it will attract and feed each of those groups. God blesses us by sending the proper workers at the right time. The only thing we have to do is provide some balance and moisture. (Even a poor balance will compost. It just takes longer.) The goal is to provide the compost pile with a good mix of browns and greens. Traditionally, half of the pile will be grasses and weeds, garden plants after the harvest, and food waste. These are the usual greens. The other half will be leaves, sticks and twigs from trees. These are all browns.
A brief look at what happens in a compost pile is interesting. It also explains why compost is so good for the soil. If we examined the minerals in compost, we would see more healthy things in the compost than in the soil around it. How can that be? How can compost contain more carbon, nitrogen, phosphorous, potassium, magnesium, boron, manganese, iron, and all the important nutrients for plants than the soil those things originally grew in? It is not difficult to understand. Plants grow and search for the chemicals they need. When they find them in the soil, they use them, and keep them. When we compost, those important chemicals are more concentrated because the composting plants and trees already found them!
Plants also take carbon and nitrogen from the air. (That process requires bacteria. Most of the growing and feeding processes depend on bacteria, but we will look at that later, in a separate article.) Those two major ingredients, nitrogen and carbon, are plentiful in the air around us, but the process of pulling them from air and putting them into the roots is difficult. When we compost, those chemicals are already concentrated in the plants we’re composting! A plant will send its roots out to find the right chemicals. It might not find enough free chemicals, so it needs to get it from the sand and clay. It will eventually get what it needs, but the energy of getting those chemicals means the plant will not produce as much fruit. When everything is readily available, plants produce lots of fruit!
Like the little plants that grow in our gardens, trees get the minerals from the ground. They send roots very deep and wide into the ground to find what they need. When we compost trees or their parts, we get all that gathered good stuff! There are big results in a little compost! However, why not make a lot of compost? Remember: everything that comes from the ground can be composted!
Now we can explore improvements and potential problems in composting. The biggest improvement is to balance the carbon and nitrogen, and provide an extra dose of the trace minerals. That simply means variety. 10 different plants will make better compost than two or three plants. Leaves and sticks from 10 different kinds of trees will be better than two or three kinds.
The other improvement is to add “concentrated” forms of the necessary chemicals. The best sources of that concentrated compost is manure, urine, and wood ash. Cows, goats, chickens, or rabbits make great concentrated (and safe) manure. In fact, their manure is often composted directly. The better way, though, is to add it to the big pile. Urine is a form of “liquid fertilizer.” It is full of the major and minor elements for gardening. Wood ash is great if you have it. It has all the nutrients of wood minus the carbon. (The carbon burns off.)
Human urine is first rate fertilizer! It should be considered a “green” when you are balancing your pile. Wood ash and urine are sometimes used as a super fertilizer mixed with water. The results can be amazing! But the best way to use the benefits of wood ash and urine are to compost them in the pile. (If you do use urine and ash directly, it must be mixed with a lot of water. It is too powerful to apply directly to any plant.) The challenge of ash and urine is that it has nothing to bind itself to. It goes into the soil and quickly washes away without the other healthy amendment of the compost. It requires a little to be added often. Mostly, the missing stuff is carbon and bacteria, fungi and insects, worms and the castings from all those creatures that God gave us.
The only two important considerations for compost problems are imbalance and bad bacteria, nuisance seeds, and poisons from chemical fertilizers and sprays. The best way to solve all of these problems is to increase the size of the compost pile and make sure it is balanced with a variety of browns and greens, keep turning it, and let it get as hot as possible. A really hot pile will reach 70C. That will kill seeds and bad bacteria in the pile, decompose many dangerous chemicals, and speed up the composting process. To get that hot, however, there must be a big pile!
By now, you know enough to cook some very good compost! We will continue to visit the compost business as time goes on. I hope you find this series meaningful and entertaining. It is a very important subject for our lives! We need to constantly work to keep the blessings of our soil that God so graciously provided.