Maybe it was the temp of 160F or the ammonia gas, but somehow I got the notion that I could cook in the compost bin and had to figure out IF and HOW I could pull it off.
How to get compost pile hot:
A hot compost pile is a delicate balance, and sometimes a freak accident, which is how I got this foolish notion of using it to cook food. It is the combination of ingredients, moisture, mass and air.
- Ingredients: Entire books are written about the ingredients and ratios for compost. For hot composting, it takes lots of finely-chopped greens. I get a garbage can of grass clippings each week when Odilon, our friendly neighborhood gardener, happily disposes of our neighbors’ grass clippings into our compost bin. Grass is a nitrogen-rich “green” ingredient has to be mixed well with compost “browns” like dried leaves, wood chips, straw (preferably chopped). I have gotten very hot compost with materials like straw bedding from sheep, and mushroom compost (which is woodchip mixture used for growing mushrooms). I keep browns on the side and mix in.
- Moisture: A balancing act between too wet and too dry. It should be damp. If you grab a handful, you should be able to squeeze a little water out. Others describe it as a damp wash cloth.
- Mass: A small pile will never be able to get hot. I have gotten hot compost with as little as 2/3 of a cubic yard (3ft x 3ft x 2ft) This is enclosed in a bin which also helps retain the heat.
- Air: Straw and wood chips also help form air pockets and keep the grass from matting up. Then I turn my pile from either twice a week or every other day to get more air mixed back in. To get hot, your compost pile needs a few days to sit and build up heat.
Why to NOT make compost that hot!
While having a compost pile at 160F/71C is good if you want to cook a meal, it is not as good if you want to use it for your garden. Somewhere above 130F you will start to smell ammonia. This is your compost pile releasing nitrogen into the air. But you want nitrogen in your garden, not in your disgusted SO’s nostrils! When I am not cooking dinner, I add dirt to my compost pile which helps absorb the ammonia and regulates the temp down to 120F. In his book “Gardening When It Counts” Steve Solomon has an excellent discussion on composting, and how dirt acts like the cooling rods in a nuclear reactor to control the process. He recommends compost piles to be about 5% dirt, and I probably end up at this amount when I keep adding dirt to cool it down.
What else could you do with compost at 160 degrees?
Beleive it or not, there are REAL trials being run on how to use compost heat being used on a farm. It’s a large PDF file to download, but really worth reading and very educational.
There were many other questions about this video that were asked on Twitter. If you want me to go into more details on other parts of the process, please add a comment and I’ll be happy to answer your questions, including (heaven forbid) post the recipe.