By Sami Grover, TreeHugger
Want to compost, but not sure where to start? Confused about the difference between hot compost and cold compost? Considering worm composting, or perhaps even grub composting?
Whether you have a gigantic garden and oodles of time and energy, or a balcony and an overbooked schedule, there is a composting technique that is right for you. Here’s a tour of the most common—and some more unusual—forms of composting.
Feel free to share your own tips with readers in the comments.
Hot composting is not rocket science, and it doesn’t require expensive equipment or capital outlay. But it does need some careful attention, and the ability to gather significant amounts of the right kinds of biomass.
You need to mix significantly more carbon-rich, woody “brown” materials with smaller amounts of nitrogen rich “greens” (kitchen scraps, lawn clippings etc). How exact you want to be is up to you, but the correct ratio is about 25 parts carbon to 1 part nitrogen. (For the truly geeky, a friend of mine has even created an iPhone app to help you maintain compost ratios!)
You will also need to spend some time turning the heap every few weeks.
While managing these hot compost bins in his community garden, fellow TreeHugger Chris Tackett found that communication is as important as building the heap itself:
“The challenge with composting in a community garden smack dab in the middle of a neighborhood is getting everyone informed about the process and where things like food scraps and grass clippings should go.
“With the “hot” bins, I wanted to layer them with the right mix of browns and greens and then let them process and break down before adding loads of new material, so we’re trying some signage to explain which bins are ‘active’ and where extra browns and vegetable peelings should go.”
With a really hot heap, in the right conditions, you may achieve usable results in just a few months.
Image credit: nancybeetoo / Flickr
Cold composting is much less-labor intensive, but considerably slower than hot composting methods. Composting bins, or piles, are simply filled up as compostable materials become available. Compost can be harvested gradually as it becomes ready by digging from the bottom of the heap. (This is much easier with a commercial composter like the one pictured here, or a custom-built one that also allows access to the base.)
Alternatively, you can build up one cold compost heap or bin over a season, and then let it sit while you start filling up the next. In my experience it can take up to a year, using this method, to achieve good, usable compost.
It’s worth noting that cold composting will be unlikely to kill weed seeds or plant diseases, so it is worth being careful about what you put in your bin. On the other hand, however, I have heard some permaculture enthusiasts argue that a cold heap will have more beneficial microorganisms that can actually live outside of the composting environment. (I am skeptical about this claim. Even hot heaps cool down and go through a secondary, cooler decomposition.)
Because cold composting doesn’t involve turning the pile, getting enough oxygen to avoid anaerobic decomposition (and the slime and smell that goes with it) can be tricky. One of the best methods is to simply add plenty of scrunched up newspaper, cardboard and other high-fiber, carbon-rich materials in with your kitchen scraps and other waste.
Cold composting is great for folks who may not generate huge amounts of organic waste at any one time, or those who simply don’t have the time, energy or interest for more involved methods. But be prepared to wait if you want to use the end result.
Image credit: jarsyl / Flickr
Worm composting, or vermicomposting, is a much touted solution for indoor composting, or those with little space. Commercially available worm composters can be purchased from garden stores, or online, or a simple system like the one pictured can be built using a few plastic tubs, and some newspaper.
Besides creating a faster composting process than cold composting, and needing much less space than hot composting, some research suggests that worm compost may help prevent plant diseases due to the beneficial microorganisms it contains. In fact, large-scale commercial composters are increasingly exploring worm composting too.
When Chris is not managing hot compost heaps at his community garden, he composts his own waste in a DIY worm composter: “The worm bin could not be any easier. I made a really basic setup using two nested plastic tubs and the worms love eating some of my kitchen waste, like apple cores, carrot tops, veggie peels, etc. Everyone should do this to reduce the amount of trash that rots in the landfills.”
Check out this instructional video if you want to build your own worm bin.
Image credit: Sami Grover
The techniques used to make leaf mold are very similar to those used to make cold compost—essentially you just pile it up and let it rot. But because leaves fall at the same time of year, this usually involves building a large pile and then allowing it to break down, rather than adding to the heap over time.
Because making leaf mold is a cold process, and because there are relatively few nutrients that could wash away, there is no need to cover the heap or otherwise insulate it. In fact, regular soakings from rain will help the pile to break down, Most leaf mold containers are little more than a set of posts with some chicken wire attached.
While the end result is much less nutrient-rich than compost, this is no bad thing. Leaf mold is often used as a mulch, or can be mixed with compost to make potting soil. And it can also be added in larger quantities than compost or manure to garden beds as a soil improver without a concern for overfeeding plants or washing away nutrients.
The bin shown here contains one year’s worth of leaves raked up from my yard. I expect it to be ready to apply by the end of the next growing season. Really, anyone with excess leaves and a garden should be making leaf mold. Even a small circle of chicken wire can be used to make small quantities for potting soil.