Here’s the notes from the mini composting class I did last night for the community. Not exactly like being there, especially because you missed dessert–dirt and worms!*
1. Invest time and energy into feeding your soil, and it will feed your plants better than you or a synthetic fertilizer can.
2. Composting diverts waste into a useful, valuable product. (Recycling!)
3. Mother Nature already composts; we’re just controlling some of the variables for our benefit.
Five Basic Elements of Effective Composting:
Browns, or Carbons. “Dry Ingredients”. Provide bulk, food for microbes. Eg: straw, dead leaves, twigs, woody garden waste, cardboard (toilet paper rolls are a staple), wood ashes, aged manure, garden soil, human and pet hair. Dryer lint and whatever your vacuum collects if you feel safe about what is in it.
Greens, or Nitrogens. “Wet ingredients.” These provide energy and get the pile decomposing quickly. Eg. Veggie/fruit peelings, green garden waste, lawn clippings (untreated!), small weeds that haven’t flowered. Some tell you not to use any cooked food as it will attract pests but I do, as long as it is straight fruit/vegetable (nothing added) and I cover it with soil or leaves.
Water. There must be moisture in the pile for decomposition to happen. Open piles often get enough from snow and rain, but covered bins will likely need watering. 40-60% moisture content is ideal; “like a wrung out sponge” is the oft-used analogy.
Air. The microbes working in the pile need oxygen. If they don’t get enough you’ll end up with a slimy, smelly mess. This is why people talk about ‘turning’ their pile, though not every pile needs frequent turning.
Life. The microbes mentioned, bacteria, moulds, worms, beetles, centipedes… All these have a part to play in the process.
No-nos-what to leave out:
Meats, oils of any kind, dairy, pet waste (some people do use straw/wood shaving bedding from herbivore pets such as rabbits), pasta, bread, rice, weeds with seeds or rhizomes, diseased plant material. These attract pests, don’t break down well, or jeopardize the health of the compost (and hence, your plants). Avoid too much citrus, as the acidity affects microbal action.
The Actual Building of the Pile
There are many types of composters you can build or buy. The ‘best’ depends on your situation: amount of food waste, size of yard, etc. I have a big open pile (my favorite) as well as a couple of black stationary bins. The open pile works more slowly but I hardly do a thing with it. The bins are faster but require more attention.
Choose a fairly sunny spot for you bin, convenient to use so it’s not a chore. Mine is right close to the back door, near where my fall leaves tend to accumulate anyway (less raking!).
Whatever system you have the basics are the same. Start with a base of woody material like twigs. This helps keep air in the bottom of the pile. Then make layers, 3-4 inches each, alternating greens and browns. Throw a shovelful of garden soil in every once in a while, and water the whole thing after each brown layer. Build this way until you have about a cubic meter-sized pile. Now just let it sit, turning it with a fork or compost aerator if you want to speed things up. Check the moisture level occasionally. Depending on the bin, your materials, and how much you turn it, you will have finished compost in anywhere from six weeks to several months.
Most people don’t build a whole pile at once though. They want to bring out a bucket of kitchen scraps once in a while and have somewhere to put them! There are a few ways to do this. You can add them to the top of an open pile, burying them with leaves, soil, etc. You can keep a couple of piles or bins going, one ‘cooking’ and one being added to; when finished, use the cooked pile and start a new add-to pile in its place; the old add-to becomes the ‘cooking’. Keep a supply of browns handy next to the bin to add as you dump your greens.
Another super easy way to compost is to just bury your kitchen scraps straight into the garden, between rows or behind bushes. As long as you don’t clump too much greens together, they’ll break down without you doing a thing.
Does my pile have to “heat up” to work?
No. It makes it faster, but it’s not necessary. Too much heat can actually be bad, killing microbes, or actually starting fires! (Don’t pile heaps of grass clippings close to any buildings you like!)
Can I still compost in winter?
For sure! Everything will freeze of course, but just keep adding to the pile and it will pick up where it left off in the spring. Another reason to place your pile in a spot convenient to the house!
What about pests like mice and flies?
Pests are usually attracted to smell, so stay away from those smelly no-nos listed above. Cover your greens with boring browns and they will be further discouraged. If mice are nesting, your pile is probably too dry.
How do I know my compost is done? How do I use it?
It will look pretty much like dirt! Shovel some off into a bucket to sit alone for a few weeks to be sure the microbal activity has tapered off before you use it. Compost can be used to top dress any garden beds, mixed into planting holes, whatever. I’m not a tiller but people will till it right into the soil before planting veggies. It is food for you soil and your plants, so extra doses for spots that seem to struggle is a great idea. It’s pretty hard to use too much.
Two other types of composting worth mentioning:
Bokashi composting, a Japanese fermentation method. Allows for composting small amounts of protein, but it’s very specialized.
Vermicomposting, using worms to help the process along. Great indoor or small scale option, though I do it too!
*chocolate pudding with cookie crumbs and gummy worms.