In this post I am going to be discussing a few different methods for composting, listing some of the steps to each method, but mostly going over pros and cons of each method. I will cite some sources at the bottom for further reading. If more information is required, use the comment section to ask questions.
Composting is something I've become quite interested in lately. I've found many different sources on how to do it, using many different methods. It seems to me that, depending on what your overall goal is, you may need to choose a specific method of composting, rather than just setting up a heap and throwing all of your organic waste into it.
For instance, a heap made from all sorts of food and yard waste may not contain the proper nutrients your soil needs when it comes time to introduce your compost to your garden. Plant yield can vary greatly, depending on the organic matter in which it grows.
I was always under the impression that taking compost from your heap and establishing it as the primary soil in your garden was a top-notch idea. According to one of my books, I was dead wrong. Compost on its own only plays a fractional part in the production of food. Adding compost to the soil that already exists, and introducing other materials as needed seems to be the ideal way of growing. In fact, the Biointensive method only asks for a 1-2 inch layer of compost on the very top of the garden at the beginning of the season, meaning that the other parts of the soil are just as, if not more, important for the proper propagation of species.
One method of composting is the "rapid" compost method. This is a simple formula which requires more work from you but yields much quicker breakdown as a result. Using something like 2/3 brown and 1/3 green ingredients, you monitor the moisture on a daily basis and turn the compost everyday as well. Within 2 weeks you have a fully composted heap, ready for use. The major downside to this method, based on the reading I've done, is that when organic material breaks down that quickly, a lot of the vital nutrients are released in gas form from the pile. Turning the heap causes air to get to the nitrogenous "green" material faster. This is why the pile converts quickly, but the problem comes from the fact that much of the important microbial life in the pile, the stuff that helps strong root growth in the garden, cannot survive in the high-nitrogen environment and the resulting compost is of inferior quality.
Now, there are 2 somewhat opposite techniques which both yield highly nutritive compost, but each has benefits and flaws. These two are the "cold" and "hot" compost methods. "Cold" composting consists of getting the proper mixture of brown and green materials, as well as a small amount of garden soil introduced to the pile. Ordinarily, one would loosen the base of the heap about 12 inches down and then place a layer of sticks on the bottom to provide a solid base for the pile. You then add the brown (dead leaves and plant matter), followed by the green (fresh grass clippings, leafy vegetation), and you top it off with some soil from the garden. The major downside to this method is the final step...in which you leave it alone for 4-6 months. The description of this method mentions potentially turning the heap once, about 2 months in, but otherwise this pile sits and works over time. As long as you have no urgency for compost, this seems to be the best method to get the most out of your compost. Not only does "cold" composting provide more useable compost for the material you put in, but it also provides compost with the most nutrients and microbial life.
"Hot" composting is somewhat opposite from cold, in that you turn the pile infrequently and maintain it more often. This method is necessary for breaking down items like "compostable plastics" made from vegetable materials and larger sticks and twigs. The heat required to consume a compostable bag of chips is upwards of 140-170, which you can achieve through "hot" composting. There are drawbacks to this method. First is the amount of human energy required to maintain the temperature. Second is the fact that, despite normal claims that a hot pile will kill weed seeds and small insects like aphids, the truth is that in order to actually be 100% effective, temperatures have to reach above 200.
I like to "hot" compost because it allows me to compost in the winter in Michigan. It also lets me throw things like compostable forks and coffee cup lids into my heap. There are a lot of places in the Detroit area using these materials now and, on the rare occasion that I purchase something that comes with vegetable-based plastics, I have a hot heap at home to biodegrade these items.
As I mentioned in my last post, I plan on expanding my garden and composting operation this summer. This plan includes trying each of these composting methods first-hand. I plan on using images, as well as updating with blog entries step by step as I go to find out just how well each method actually works. With any luck, they will all work well and I can send soil samples to the MSU extension office in Lansing to have the nutrients in each heap tested.
And that is my diatribe on composting. Obviously, there will be more compost conversation coming this summer, so if you love organic matter, keep checking back.
More info/citations:
Rapid Composting
Ecology Action: GROW BIOINTENSIVE method
