What I Learned to Help my Compost Pile

 When I was a kid on the farm, one of my little household jobs was to take the strainer full of scraps to the garbage pile out back by the burnpile. These were vegetable shavings and pieces from food prep as well as leftovers from the table. That was my first experience with a "compost pile." Later when I was an adult gardener, I began to understand how decomposing vegetation played an important role in fertilizing the earth's soil, and I made a more deliberate compost pile. Now, living at Prairie Hill Cohousing where my personal garden space is convenient to members for dumping grass clippings and pulled weeds, I have what is definitely the biggest compost pile of my life. I always knew there were processes taking place below the surface, and that if our pile heated up, it was a good sign that something important was happening. But now that I have done some research on composting, I am amazed that I have been such a total novice on this subject! Why did I never learn more about this important process?

I hesitate to even write a post about composting, for I imagine many of you know much more than I do. Clearly my big pile of dead material at the head of my garden needs more care than it gets, as well as some different ingredients in order to do well. I have learned so much, and hopefully it will help me to aid the composting process in my pile. For those who need a refresher about composting, I'll give you a scratching-the-surface description of it: what happens when living things die and decay, and how we can speed up that process. Without our help, dead things will compost eventually. It's done with the aid of water, air, and tiny microscopic creatures. But if we want to help the process along, and more quickly turn out compost to use in our gardens, there are many things we can do.

First of all, it would be good to remember all the benefits of what we call compost (the end product of decomposition). This rich material restores nutrition to the soil, improving not only fertility but also water-holding capacity and texture. The nutrients consumed from the soil by the original plants or animals are returned to the soil as they decay. Compared to store-bought artificial fertilizer, this mix of composted ingredients is a much more balanced medium. It contains not only minerals and other nutrients, but also microorganisms, enzymes, and many small inhabitants (for example earthworms and millipedes whose digging brings important air down under the surface). All of these things work together to enrich the soil.

Soil microorganisms are the workers that transform dead debris into compost. What I never knew is that this process only works well and quickly if there is a balance of four important things in your pile: material that is carbon-rich, material that is nitrogen-rich, water, and oxygen. And for the microorganisms in your pile to work with absolutely the most efficiency and speed, the ratio of carbon-rich and nitrogen-rich ingredients needs to be approximately 25:1 (25 parts carbon-rich to 1 nitrogen-rich). The experts say that it makes more sense to aim for  4:1 ratio, since it is more achievable. Carbon-rich ingredients are things like wood chips, dry leaves, straw, and twigs. Typical nitrogen-rich ingredients are kitchen scraps, grass clippings, and fresh weeds. Oh my! My compost pile is made completely out of the nitrogen-rich ingredients!! Not good! So to do my compost pile a favor, I should find some straw and maybe sawdust to mix in (no dry leaves in this season yet). Apparently, without a mix that is heavily in favor of the carbon-rich ingredients, the composting process will proceed much, much slower. 

Another thing that helps a pile like mine to decay is introducing air (specifically oxygen). That means turning the pile. You can understand why some folks have special containers for their compost, containers that turn. For my simple pile in the garden, I'll need to use a pitchfork and some robust muscle. But I can do that. (Though not on these 90 degree days we're having in Iowa right now!). Enough water is also important, and since we are in a minor drought here presently, it would be good if I not only watered the vegetables, herbs and flowers in my garden every other day, but also the compost pile. 

If you're like me, you're curious about who the creatures are in the pile who diligently turn that raw material into rich compost. And I found out that there are three categories of microorganisms that play the starring roles. The temperature determines which ones are active. For cold temperatures, as low as 28 degrees F, the "psychrophiles" get going. This group is made up of bacteria, lichen, algae, phytoplankton, fungi and insects. They digest the carbon-rich materials (the rougher, brown stuff), and as they do this, the temperature in the pile gradually rises. Once the temperature gets up to 60 or 70 degrees (either from the work of the psychrophiles or the season warming), another group, the "mesophiles," can thrive. They are made up of mostly bacteria and fungi. Using the ingredients of carbon, nitrogen, water and air, they can work rapidly to decompose the raw materials and raise the temperature of the pile up to 100 degrees. And then it's the heat-loving bacteria and fungi that kick in. They are called "thermophiles", and they can raise your compost pile to an astonishing 155 degrees or higher. This will kill disease-causing organisms and also any weed seeds that were in the original pile. 

Evidently, if you provide the right ratio of components, regularly turn your pile, and make sure there's enough but not too much water, you can get finished compost in two or three weeks. For someone like me, who is at the other end of the spectrum, it might take months or years. But that's OK with me. I'm not in a hurry. My main interest in having a compost pile is to make sure that waste products we often put out for the garbage collector instead find a more natural home and can go through the cycle of decomposition and nourishing the soil. 

It's been a real education for me to learn more about the inner workings of compost piles. Especially, it's good for me to know about the best ratio of various ingredients, which should help me create a pile that heats up more quickly. As you've seen, this article just scratches the surface. If it engages you, there's much more to learn about how to create compost with various types of structures that make turning and holding easier. And yet still, to me, the most important and inspiring fact has to do with this process that happens all over the earth, as living things die, decay and return to nourish the soil. It's been here all along, long before humans decided to manufacture composting machines.