Fall Composting

Fall is composting season. Autumn leaves are the main ingredient in my backyard compost pile, and mature trees in my yard (and around the neighborhood) supply plenty of material for the rich, loamy compost with which I enrich the soil in my garden beds. No matter where you live or what you grow, a wheelbarrow full of crumbly brown compost, cool and moist, is a powerful gardening tool. When you work a shovelful of it into the soil, it improves the soil's structure, adds nutrients and enhances drainage.

Some people are very particular about making compost, but it's an easy process. For a basic compost heap, all you need is a bare spot about three feet square. You can make it in a special container, or just pile your raw materials up right on top of the soil.

Start with a mix of autumn leaves and grass clippings. The leaves (which supply carbon) and grass clippings (which supply nitrogen) generate heat as they decompose into a rich, organic loam. The leaves and the grass should be well mixed, and a good way to do this is to mow the autumn leaves right on the lawn — with the bagger on the mower — chopping the leaves up and cutting the grass at the same time. The ratio of leaves to grass clippings in a lawnmower bagger changes with the season: there will be more green (the grass) in early fall, and more brown (the leaves) in late fall. Empty the bagger directly onto the heap, and walk away.

Carbon, nitrogen, air, and moisture are all you need to make compost. A fluffy mix of leaves and grass already contains air pockets and moisture. Leaves and grass alone will suffice, but vegetable scraps from the kitchen — broccoli stems, apple cores, potato skins, banana peels, tea bags, coffee grounds, and eggshells — give the bacteria in the heap even more to work with.

My husband and I keep a garden fork by our heap to toss leaves over the kitchen scraps, so they're always buried in the pile. Decomposition goes faster if the individual pieces are small, but just about everything breaks down in time. Recognizing a peach pit in finished compost will remind you of the pleasures of summer, and will certainly not lead to a weedy invasion of peach trees in your flower beds.

One of my neighbors makes his compost in a classic three-bin system, with one bin for fresh ingredients, one for partly decomposed compost, and the third for finished compost, ready to use. It speeds things up if you turn the compost by moving it from one bin to the next after a month or so, but my husband and I make our compost without bins at all — we have one pile for "working" compost and one for "finished" compost. The process takes about a year. You can make compost faster if you are prepared to turn your heap frequently. The addition of fresh grass will cause the heap to heat up to as much as 130 degrees and will speed decomposition. We allow our compost to take its time, and find that when the compost is ready, we are, too. We especially like to put in a shovelful every time we plant something: we're amending and improving the soil in our garden, one hole at a time.