Compost is often called “black gold”. I think it’s black magic myself, although it’s more like dark brown, and there’s no magic required to make it.
It even works in winter. We keep a plastic garbage can beside the back door where we dump the kitchen scraps on a cold day. To let in oxygen and prevent anaerobic breakdown, it’s drilled with holes at about six-inch intervals. Yes, sometimes the contents freeze and the process stops, but once a thaw sets in it starts up again. By spring we have a nice mushy mess of partially decomposed kitchen scraps to add to the big compost bins at the back of the garden.
Compost is nature in action, with bugs and micro-organisms breaking down once-living things into healthy humus. It happens on the forest floor all the time. The smelly manure pile on my uncle’s farm was compost writ large. It smelled earthy and strong, but not unpleasant– at least not a day or two after the latest steaming offering had been added. I used to get bushels of the well-rotted stuff to bring back to the city for my suburban garden.
Then I started my own compost pile in a corner of the back yard–but not with animal waste, I hasten to add. (Never add animal products, fats, dairy products or leftover dinner to compost or it will smell really bad and attract local wildlife.) I dug a foot-deep hole about four feet long and added plant prunings, garden debris, fallen leaves, vegetable scraps and peelings, crumbled egg shells, even wood ashes from our fireplace, topped with a shovelful of earth every now and then. I laid it over with a tarp.
It was easy and it yielded nearly a whole wheelbarrow of compost in one summer. But a neighbour asked if I was competing with the city garbage dump, so I acquired a couple of brown plastic compost bins the municipality was giving away. They looked better, but to be honest they didn’t do the job as well. They never seemed to heat up enough to break down the plant material, probably because they were too small. It took two years to get a couple of wheelbarrows of compost from the two of them.
Then providence bestowed on me two large bins made of removable wooden slats, built by a neighbour who was moving (I could have had three, but my space –behind a vine-covered fence and arbour at the rear of the garden, where they’re hidden–didn’t allow). Because they’re four feet square and high, the contents can build up enough heat at the core to break the material down quickly, in the process killing unwanted contents like weed seeds and insect eggs. I put my hand into the mess last summer and it was like sticking it into a hot bath.
Three bins might be more efficient and give me finer finished compost, but two work for me. With three I could put fresh material into one, allow it to partly break down and in a few weeks move the smaller pieces into the second bin, where it would break down further. Then it would go into the last bin to become crumbly and fine.
In my system, all the new material is thrown into the first bin, then the most decomposed stuff is moved to the second bin by the end of summer, leaving lots of space for dead annuals and perennial tops in bin one when the garden is put to bed for winter. The material in the second bin is usable the next spring, although to get the best it’s necessary to sift it. My compost maybe isn’t as fine as the ideal. Bits of sticks and unidentified lumps show up, but these pieces break down in the garden.
I confess that some years I’m just too busy or disinclined to move the small bits into the second bin, and both bins take whatever they get. In the end, it all turns into compost.
I can’t believe how fast the process is –one week the veggie scraps and dead flowers reach the top of the bin and the next they’re down several inches. I’ve never run out of space. I do help the process along by cutting plant stems or thick leaves, like hostas, into smaller pieces, and I leave woody branches and stems for the municipal garden waste pickup.
Compost happens no matter what you do, but there are a few basic “rules” to heed.
Use the biggest container you can: Purchased plastic bins are usually too small to heat up well. A four-by-four-foot bin made of wood or even wire fencing is better. (The Resource Recovery Board Nova Scotia has a page on how to build several kinds of composters.) If the core temperature reaches 140 degrees Fahrenheit most of the bad bugs and weed seeds will die. A compost thermometer helps keep track–if the compost isn’t heating up, it may need a jolt of nitrogen in the from of grass clippings or a sprinkling of organic nitrogen fertilizer, such as blood meal.
Feed the beast: Add material high in carbon (brown materials like dead leaves and frost-killed plant tops, sawdust and fine wood chips, newspaper) and nitrogen (grass clippings, vegetable waste from the kitchen, green plant parts). Never add animal products. Add material in layers if you can, and throw in a shovel or two of garden soil every now and then to help things along and add more local bugs.
Water when necessary: I seldom have to add water because most material (eg carrot shavings, orange rinds) contains moisture, but if the pile seems dry give it a light spray from the hose or watering can. The mixture should have the feel of a damp sponge–in other words, don’t make it soggy.
Give it air: Use a garden fork to turn the contents over and let in some oxygen, which helps the decomposing process. You can buy an aerating tool that has two blades the retract as you push it into the pile, then open as it’s withdrawn. It’s handy, but it takes as much muscle power as a pitchfork and doesn’t work any better.
If you’ve got questions, you might find the answer at 25 Questions About Composting from the Composting Council of Canada