Hot Composting Recipes for the Advanced Gardener
by Paulette Mouchet
Dr. Elaine Ingham, a professor at Oregon State University and founder of The Soil Foodweb, Inc., which provides farmers and gardeners with information on the health of their soil, has two recipes for making compost-each tailored to the type of plants that will be grown.
Bacterial Dominated Compost-used for annual row crops
25% (by weight or volume) high-nitrogen material, such as legumes or fresh manures. If poultry manure is used, drop this to 15%; if pig manure is used, drop it to 5 percent.
45% "green stuff" to feed bacteria-grass clippings, coffee grounds (the beans are green when harvested). If you used pig or poultry manure above, increase the percentage of green material.
30% woody material, such as hay, straw, wood chips (after the scent of volatile compounds has disappeared), dry brown leaves (but not solely oak leaves).
Fungal Dominated Compost-used for perennial plants
25% high-nitrogen material
30% green material
45% woody material
After making the pile, it should heat to 135 degrees Fahrenheit within 24 to 72 hours. If not, it doesn't have enough nitrogen and/or pesticides in the material may have killed decomposing organisms. Add a 1% sugar solution to the pile to feed the bacteria that can degrade the pesticides. If those bacteria have already been killed, inoculate the pile with a commercial bacterial preparation.
When the pile reaches 155 to 160 degrees Fahrenheit, it should be turned so beneficial organisms aren't killed by excessive heat. After turning the pile three or four times, the organisms should have "used up the juicy material" and protozoa should be proliferating. The temperature will now drop below 135 degrees Fahrenheit. When the temperature is around 115 degrees Fahrenheit, nematodes start to proliferate.
Allow the pile to sit until it reaches the ambient air temperature, indicating that it is mature. If you turn it at this point and it heats up again, it was not mature. As mature compost ages, the diversity of microbial species that populates it increases for about 6 months; then diversity decreases, and after 2 years, it is no different from topsoil as far as microbial life.