Composting Basics

We have two large maple trees in the backyard, so late fall means dragging leaves to the curb to be picked up by the city. The last few years, I’ve started using some of those leaves for compost. I had not done much composting before so I’m learning as I go.

Composting, they say, is the new recycling. Unlike recycling, which from the consumer’s perspective basically means throwing things into the blue can instead of the brown one (with disappointing results), composting is its own do-it-yourself project. And it doesn’t require specialized tools or sophisticated planning.

The process of composting takes organic material from your yard and kitchen and turns it into nutritious dirt for plants. You can make it as complicated as you want, but you can also do it pretty simply and on a small scale.

So where to start? You need some kind of container, loosely defined. It could be wire fencing or some old pallets fastened together. As a general principle, since you’re making dirt, a fancy design isn’t necessary.

I have a black plastic compost bin called the Earth Machine. It has a lid that, for some reason, locks on when turned counterclockwise, the opposite of the “righty tighty” rule. Slits in the side allow air to circulate and a panel at the bottom makes it easy to scoop out the finished compost.

The main ingredients in compost are known as “browns,” which supply carbon, and “greens,” which supply nitrogen. Generally the advice is to have an equal amount of browns and greens, though some experts suggest somewhat more browns than greens. You’re not going to be measuring everything but that’s a rough guide.

The most common source of browns are those fallen leaves. Dead flowers and plants that you’ve cut back for the year are good choices as well. Supposedly newspaper and cardboard also work, but for me they always raise the question of what’s in them: inks, coatings, and so on.

Greens include a greater variety of options. One common material is fresh grass clippings, though when my kids dethatched our lawn this summer, the old dead grass they pulled out would be considered a brown item. Most of the other greens are the fun things, the food scraps that you would have sent to the landfill.

You can read a lot of advice that breaks down the kinds of food that you should or should not compost, but you can basically sort by food group. Fruits and vegetables, along with all their peels, rinds, cores, and trimmings, are compost material; dairy and meat are not. Edge cases do exist (onions are the subject of much debate) but no one kind of scrap is likely to sabotage your dirt making, especially if you include a good variety.

Besides the right ingredients, the most important factor for effective composting is the size of those ingredients. I remember when I used to belong to a community garden and people would throw anything in the compost bins: a whole head of lettuce, half a watermelon. Those things will decompose . . . eventually. If you want to have compost in the foreseeable future, though, you have to chop everything up small.

How small? As small as your time and patience allows. I usually think of one inch as a good maximum size, but obviously that requires some adaptation for a melon rind, potato peel, apple core, and so on.

Which brings us back to those leaves. My first year of composting, I threw the leaves into the composter as they were, and they took a long time to break down. The next year, I used a secret weapon: the lawnmower. By raking the leaves into a low pile and running over them a few times with the mower, I produced a compost-ready leaf confetti. I think this tactic would work better if I attached the bag to the mower; I always use the self-mulching setup and haven’t bothered to change for this project. As it stands, I rake the shredded leaves into a pile and use a snow shovel to dump them in the composter. This does create a bit of a mess all around, but I am making dirt, after all.

I try to start at the bottom of the pile with a layer of brown material that has a more open structure — maybe twigs or stalks — so that air circulates all the way through. Ideally the compost is then laid down in layers (what’s sometimes called “lasagna compost”) but the reality is that the leaves show up all at once in the fall while the vegetable peelings come a little bit at a time. So I generally fill the composter with shredded leaves, then turn a layer of the leaf bits over the top of any green material that I add. For this reason a pitchfork or even a stick is helpful to have around. 

Composting doesn’t require much beyond those browns and greens. I add a few shovelfuls of garden soil to the mix, with the idea that it already contains a lot of microorganisms to speed the process along. Also, compost is supposed to be kept moist, so watering regularly is a good practice. Honestly, I don’t usually bother to do that. I do leave the lid off the composter so the rain falls in, but does that also allow more moisture to evaporate? Not sure. Finally, I try to turn the compost every week or two so that the part in the middle moves to the edge and vice versa.

The nice thing about composting is that it does okay with a lot of neglect and misjudgment. If you do a less-than-perfect job with any of these steps, generally the worst you will do is make the composting take longer. I have been filling my bin with leaves in the fall, then adding as many greens as I can in the late fall, winter, and early spring. Composting slows down when the temperature drops, so not much is happening in the dead of winter, but by early summer the fresh dirt is ready to use, just in time to give a boost to flowers and garden vegetables.