How to Build a Compost Pile

Categories|Earth-Friendly Strategies, Garden 101, Soil and compost

Organic gardeners revere compost. Compost improves soil’s texture, its fertility, its ability to hold moisture, and the amount of microorganisms it can host. Compost feeds the soil, which in turn makes for healthy plants. And most amazing of all, it can be made for free from leaves, kitchen scraps, and bits that might otherwise go in the garbage.

Composting is basically about throwing a bunch of stuff in a pile and letting it rot. Leave it alone, and you’ll get compost in a year or so. Turn it over a couple of times, be a bit more selective about what you put in, and you can speed that process a lot.

Compost Materials

Anything that was once alive can go into a compost pile. Compost materials are usually categorized either as “green”—those containing a lot of nitrogen—or “brown”—those with a lot of carbon.

Green materials are juicy or sticky.

  • freshly pulled weeds
  • kitchen scraps
  • grass clippings
  • coffee grounds
  • manure from herbivores

Brown materials are dry and crunchy.

  • leaves
  • straw
  • shredded paper or newspaper
  • wood chips
  • sawdust (from non-pressure-treated wood)

What Not to Compost

Anything that can cause a stink, attract rodents, pass on disease, or encourage invasives.

  • meat, bones, and fats
  • dairy products
  • manure from carnivorous animals like humans, cats, or dogs
  • poison ivy
  • diseased plants
  • anything treated with chemicals
  • ashes from coal or charcoal

Building the Compost Heap

You can make a great compost heap by creating a ratio of about one to two parts “brown” materials (the dry, crunchy ones) to one part “green” (the sticky, wet ones). Don’t worry about measuring them. Just dump in a layer of green and then about an equal volume of brown.

The soil beneath your compost heap will become some of the best in the garden. So if you can, build a pile right on top of a future bed! Or start a heap in a slightly shaded, out-of-the-way area.

You can use a compost bin or just create a free-form heap. If you want to use a bin, you can create a cheap compost bin from a plastic garbage can with a tight fitting lid. Cut the bottom completely off, then drill the sides with several holes.

Start your pile directly on the soil, not on a paved surface.

  1. Dump a layer of damp, green material in your bin. Water it.
  2. Add some brown materials and a little more water. Throw a couple of handfuls of soil in there to introduce microorganisms.
  3. Continue alternating layers. Or you can just dump material in as it becomes available.

Speeding Up Your Composting

To speed up how fast your compost breaks down:

  • Chop materials into smaller pieces before introducing them to the pile. The smaller the stuff that goes into your heap, the faster it will break down and produce compost.
  • Keep the heap about as moist as a wrung-out sponge. Cover the heap with a tarp or lid to keep heat in.
  • Periodically introduce more air into the heap by “turning” it (remixing the materials).

Microorganisms use air at the center of the pile as they break down materials, producing heat in the process. As they use up the air, the pile compacts and cools. “Turning” fluffs up the pile, introduces more air, and revs up the microorganisms, producing compost more quickly.

  • Stick your hand into the heap a couple of inches. If you feel heat, leave the pile alone.
  • If there’s no heat, turn the pile. Use a fork to stir it up. If you’re using a garbage can without a bottom as a bin, just lift the can straight up and set it next to the pile, then fork the pile back into the can.

If your heap is smelly, too wet, or attracting insects or critters, add some more brown stuff and turn the pile. If the pile isn’t heating up or breaking down, add green stuff and turn the pile.

The compost is ready to use when it has broken down into what looks like dark, rich soil. Move aside the top layers of the heap and dig out the compost from the bottom. You can set it aside to age for a while, put it through a sieve to refine it (and toss any chunky bits back into the pile), or put it to use in the garden right away.