Not everyone feels compelled to make compost in 14 days. It just seems like too much work for some of us. However, many people are certainly interested in making the compost process faster.
By learning about the key factors in making fast compost we can begin making our own compost piles more efficient, regardless of whether our compost is finished in 2 weeks or in 2 months.
A popular method of composting, known as the Indore Method, involves piling carbon rich and nitrogen rich materials in alternating layers and letting them stand for a year, after which they are ready to use. Many composters use a modified version of this method, by turning their pile every few weeks or months in order to speed up the process. These methods produce good quality compost with minimal effort. Some disadvantages are that nutrients are lost to leaching due to rainfall, some weeds and weed seeds are not killed because the pile may not get hot enough, and the process can take up to a year to produce finished compost.
A faster method of composting was introduced by Robert D Raabe, a professor of plant pathology at the University of California, Berkeley. Commonly known as the "Berkeley method" or "fast composting", this method produces finished compost in as little as 14 to 21 days.
Let's look at some advantages and disadvantages of fast composting.Advantages of fast composting:
If there is one secret to making fast compost, it is finely shredding the carbon rich ingredients such as fallen leaves, hay, straw, paper and cardboard. Shredding increases the surface area that the compost microbes have to work on and provides a more even distribution of air and moisture among the materials. The type of chipper or shreddder used is not important, provided it can handle the materials. Rotary lawn mowers can also be used by for shredding leaves by running the mower back and forth over a pile a few times although this method is not quite as good as using a shredder.
Nitrogen rich green materials such as manure, vegetable wastes and green plant prunings can also be shredded. Soft succulent materials do not need to be shredded because they break down very quickly in the compost pile.
If you don't have a chipper or shredder you can chop your materials into ½" to 1½" pieces with pruning shears. It takes a fair amount of effort but the results will be worthwhile.
It's important to have the right balance of materials in our fast compost so that it breaks down as quickly and efficiently as possible. The bacteria in our compost need both carbon and nitrogen to function; carbon for energy and nitrogen for protein synthesis. For every one unit of nitrogen used by the bacteria they also consume about 30 units of carbon. Therefore, in order to keep the bacteria working efficiently we need to create a compost pile that is about 30 parts carbon to 1 part nitrogen.
Since most compost materials don't have a carbon to nitrogen (C:N) ratio of 30:1 we need to combine our materials so that the total mixture will be as close as possible to 30:1.
For more information on obtaining the right carbon to nitrogen ratio see making a compost pile.
The original Berkeley method involved the layering of carbon and nitrogen materials but today, many composters mix all the materials together into one large fast compost pile.
The jury is out on which of these options helps the pile to heat up faster. Choose whichever option you feel most comfortable with. For the purposes of this article we will mix all of the material together. If you choose to layer your materials the making a compost pile section of the site will be helpful.
Once your compost materials are shredded, mix everything together into one pile. If the pile feels dry add moisture and mix thoroughly and evenly. If you are unsure of how moist your fast compost pile should be check out the measuring compost moisture area of the site.
The minimum size of your pile should three feet wide and three feet high. For best results, try to make your pile 4 or 5 feet on each dimension. Place a piece of carpet or plastic over the top of the pile to help trap the heat produced by the pile. If the fast compost pile was made correctly the internal temperature should rise within the first 24 hours. Dig into the pile and remove a handful of material from the centre. The material should be warmer and darker than the material at the outer edges of the pile.
Within two days the compost pile should be ready to be turned for the first time. Compost bacteria need plenty of air to survive so it's best to turn more rather than less frequently. Move the material from the outer edges of the pile into the middle. The pile should be ready for a second turning after another day or so. At this stage the material should start to look like a bit like finished compost.
At the two week mark if everything went as planned the fast compost should be nearly ready for use. It may not be entirely finished heating but it should be nearly finished. It should be safe to use once the temperature has fallen below 100° F.