Last Sunday I harvested compost from two of my bins and spread it on some places in the garden that really needed a boost. It was so satisfying: I love the way the compost smells, it’s fun to see the product of all those banana peel s and coffee grounds, and although I never thought of myself as a green thumb when I was younger, I do have a really kickass garden. OK, I confess, I had a younger friend help with the harvesting . But I did the spreading, and I made the compost….

So, since I’ve been at it, and since there have been a number of questions in the messages over the last year or so about composting, so I thought I’d write something on both theory and practice of creating and using compost.

Compost enriches the soil in many ways: it adds organic matter which contributes nutrients to the soil, it loosens the soil and makes it easier for roots to establish, it increases the ability of the soil to hold plant-available water, and it enables the soil to hold nutrients. Organic matter is a major structural component in binding soil particles together. It Improves tilth (the ease of working the soil) and strength of soil structure and decreases soil erosion. So when you add compost to your soils, you’re increasing the plants’ access to both food and water. Compost also contains lots of microorganisms, which work together with plants’ roots to enable them to take up food. Often, sick plants can be nursed back to health with the use of compost.

Compost also replenishes soil that’s been over-fertilized or herbicided. Chemical fertilizers, such as the ones you buy in most big box stores – you know, the ones that promise ‘miracles’ or ‘vigor’ - will, over time, kill off most or all of the microbes in the soil. Compost will restore them, and if you manage your compost, you can even produce soil that has the right kinds of microbes for the plants you want to grow.

So how do you get started?

First you need a place to start your compost. It’s good to choose a site that is convenient (so you’ll actually use it), has a hose available, is protected from the wind, in a place with decent drainage, and close (ish) to where the compost will be used. I have three compost bins: one’s just outside the kitchen door, and I usually put my food scraps in it. It compresses down really nicely, so I don’t worry about overstuffing it. Another is by the back fence, next to the garage. I use it for plant waste, and it does get overstuffed and the plants break down slowly. Also, I’m really lazy about harvesting from it. The third is between my house and my neighbor’s, to encourage them to contribute their food waste. It’s the biggest of the three, but also the hardest to harvest from.

Consider your system. You can do compost with something as simple as a chickenwire enclosure, but not everyone wants to put food scraps where raccoons have access. Also, some neighborhoods don’t take kindly to permeable structures. Some municipalities have ordinances about compost, so if you think yours might, it can’t hurt to check. It’ll probably be easy to find out online. Ask around and see what others in your area are using. You can also buy compost bins, both at hardware stores and garden centers and online. The city of Chicago makes compost bins available at a deep discount to residents once or twice a year. Maybe your municipality does something like that too. (We can also buy rainbarrels, but that’s another story.) The ones I got from the city have tops that lift off and doors at the bottom that you can remove to harvest the completed compost. I also have another bin that comes in pieces. Picture a square about 2’ across with a perimeter of plastic about 6” high. Three of these, one on top of the other, constitute the compost bin. To harvest you have to lift off each square of plastic, put the top one next to your current compost bin, and transfer the undecomposed material into it. Then you do the same with the next one till you get down to the good stuff. You harvest it and reassemble your bin next to its previous location. Frankly, I wouldn’t get another of these again: big pain in my you know what. You can also buy rotating drums that will process your organic material much more quickly into compost. You have to turn them pretty regularly but then you get compost in a few weeks. These are good if you want compost quickly, but they’re more expensive. I’d suggest doing an online search so you can see what’s available and then figure your budget and needs.

In my soils class we learned that the optimal size for a compost pile is one cubic yard. That’s a yard by a yard by a yard. It doesn’t sound big, but it produces a lot of compost. Anything bigger doesn’t get hot enough in the middle, and anything smaller doesn’t have the mass to maintain heat and moisture. But don’t get all fussy about it – just do it at this point, and later when you’re sold on the process you can get fancy.
You can put most kitchen scraps in your compost, but don’t put meat, dairy, or oils or fats. So any vegetable matter, fruit peels (I put peach pits in, because they’ll add texture to the soil), bread, coffee grounds, coffee filters, tea bags, rice, pretty much anything but meat and dairy. Chop up the big stuff so it breaks down more easily – I slice banana peels, chop up melon rinds, etc. Add your leaves in the fall and your mown grass, unless you’re smart and just leave it on the lawn. You can even persuade your neighbors to let you add their leaves and grass too! The more grass you add, the better the compost will be for vegetables and annuals; the more leaves you add, the better it’ll be for trees, shrubs, and perennials. (Annuals like their nitrogen from nitrates, and green matter help that. Woodies and perennials like their nitrogen from ammonia, and brown matter helps that. Green matter fosters the growth of bacteria, which produce nitrates; brown matter supports fungi, which produce ammonia.)

Don’t put any weeds in the compost that have seeds still attached, and don’t put in diseased plants. Also no manure from animals that eat meat. It’s a good idea to shred some newspaper from time to time and include that, and it’s also smart to add some soil from your garden, because it will contain the microbes and other organisms that decompose the stuff you put in. The microbes will increase in the compost, and when you add it to your soil, you give your garden a booster shot of the organisms that help them take up nutrients and water.

Very smart people go into their compost from time to time and poke it around so more air gets to it. In some composting systems, this is hard to do if you’re short, because the angle for getting a pitchfork in is hard on the back. It never hurts to have taller friends or family. Compost also needs some moisture. Some systems allow some moisture from rain to seep in; if yours doesn’t, it can’t hurt to add some water from time to time so the material has the consistence of a damp sponge. You want the compost to get very hot; that’s part of what promotes decomposition, and it will get very hot in the center, even if you just dump it on a pile and put some chicken wire around it, but it will get hotter faster in a black plastic compost bin. In winter it will freeze, which won’t help but won’t hurt either.

I know people who make their own compost teas, and if you’re interested I can write about how to do that, but it does require some equipment.

I hope you’re having fun in the garden if you live in one of those warm places that can grow year-round. If you’re stuck in the north, though, we’re moving into catalog season, so that has its own fun. If you haven’t done it yet, this is a good time to make notes on what you did in the garden this year, what looked great – and what didn’t – and what you need to remember for next season.