A couple of years ago, I came across the Berkeley method of hot composting. Developed at the University of California, Berkeley, it’s a fast method of safely composting organic materials in just 18 days.
I first became interested in hot composting because I had a lot of mature weeds that I wanted to compost – but I didn’t want to deal with all those weed seeds germinating in my garden from the finished product. Since hot composting maintains a temperature within the compost heap of 130-150 degrees, not only are most weed seeds destroyed, but most pathogens from any diseased plant material are destroyed as well.
I followed the instructions I found, put together a good hot compost pile, including all those troublesome weeds, and was really delighted with the results. I was officially hooked on the method, but since gardening season was over, and winter coming quickly, I knew any further hot-composting efforts would have to wait until next year.
It was a stormy day in January, as I was gathering eggs and pining for Spring, that I looked down at the deep layer of bedding on the chicken house floor. I suddenly saw it in a whole different light.
30 parts carbon, 1 part nitrogen.
That happens to be the perfect balance for a good hot compost pile. And from what I could see, the deep layers of pine shavings, straw, and chicken manure, mingled with a few feathers, looked to be just about the same balance. Could I really just clean out the deep litter from my chicken house, come spring, and turn it into gorgeous, garden-ready compost in just 18 days?
It was an experiment waiting to happen, and when I’m itching to try an experiment, I’m not the most patient person. Spring felt so. far. away.
How to Compost Chicken Manure in 18 Days
While waiting for sunshine and flowers, I brushed up on everything I knew about the Berkeley method of hot composting. For the definitive work on the method, here’s a link to the paper published by Dr. Robert Raabe, the professor behind the study. The basics of the method are this:
1. The materials to be composted must be chopped fairly small. 1/2 to 11/2 inches in diameter is ideal.
2. The Carbon to Nitrogen ratio must be correct. 30 parts Carbon to 1 part Nitrogen is the goal. (If you’re correctly doing the deep litter method, you’ve been adding shavings all winter, so the contents of your chicken house floor should contain a LOT of “brown” material-the shavings or straw-and should not be a big caked pile of manure.)
3. Moisture content of the pile must remain around 50%. So not soggy, soppy wet, but definitely not dry either.
4. To create the necessary heat, a minimum mass is required. Dr. Raabe’s paper specifies a pile of at least 36x36x36, and he states that if the pile is under 32″, this method will not work. I thought this quote was interesting: “High temperatures favor the microorganisms which are the most rapid decomposers; these microorganisms function at about 160 degrees (F) and a good pile will maintain itself at about that temperature.”
5. The pile needs to be turned to prevent overheating, and allow for aeration. While many of the resources I’ve seen about Berkeley-method composting suggest waiting four days after building the pile, then turning it every other day, the author actually suggests turning daily for the most rapid completion of the composting process.
6. Don’t keep adding to it! While we might be used to adding to our compost piles daily, it’s important not to add to add to this one, since the added materials will be starting the decomposition process from scratch. You want the whole pile to end up as a nice finished product all at one time.
7. Nothing extra is needed. Dr. Raabe makes a point of specifying that as long as the nutrient balance is correct, your pile will begin the decomposition process nicely on its own. No activator materials should be needed.
8. If done correctly, your pile will reach high temperatures within 48 hours. If you can reach into the pile two days after building it, and it’s not uncomfortably not, then something is off. It’s either too wet, too dry, or the pile doesn’t contain enough nitrogen (“green” materials). If it’s too wet, you can rake it out to dry, then pull the pile back together. If it’s too dry, add some water. And if you’ve realized you erred on the side of too many brown materials, then adding some grass clippings or manure can balance things out and kick the process into gear.
9. The pile shouldn’t smell bad. It should be earthy. If you smell ammonia, that’s a sign that the pile is too high in nitrogen. It’s recommended to add some sawdust to help balance out the C:N ratio. If a pile is too high in nitrogen, it can “burn out” too quickly, before all the materials are thoroughly composted.
By the time spring came, I’m not sure I’d ever been quite so eager to clean out my chicken house. It’s a pretty sizable chicken barn really, so I had enough litter to make two piles. Remember, the hot composting guidelines call for a pile at least 36″ all the way around.
The first pile I put into a three-sided enclosure made with pallets. I heaped it right up to the top. The second pile I left in the open, just piled up nice and high.
I hosed them both down just enough to damped them through.
The enclosed pile I turned daily, like the original paper from Dr. Raabe suggests. The other, I turned every other day, as suggested by several other hot-composting sources I’d read. We got just enough rain that the piles never dried out completely, but were rarely downright soggy.
I found that the enclosed pile maintained a higher temperature, and stayed a bit more damp than the open pile. I also found that it decomposed a bit more quickly.
The pile in the enclosure was starting to welcome worms, and was looking crumbly, brown, and beautiful on day 17. The open pile reached this stage on day 21. I really think that even though the open pile was turned less frequently, the real difference is that the pallet enclosure helped maintain the heat of that pile better, aiding the faster decomposition.
We had a cool and damp spring, so at the time of this experiment, days were averaging 60-65 degrees, while evenings were in the higher 40s.
I was very pleased with the results of both piles. Both were well-composted, sweet and earthy smelling, and had lots of worms moving in, as I loaded up the compost to pile onto the garden beds.
For tips on how to properly use the deep litter method, I think the Frugal Chicken has the best article on correctly using the deep litter method.
Now that I know how to compost chicken manure in 18 days, this will definitely be my go-to method for utilizing the contents of the chicken barn floor, every time I do my spring cleaning! Hope it works well for you too!
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