Composting is a little like cooking. Anyone can do it, but doing it well and in large quantities is an art that demands skill and dedication.
I’ve experimented with different methods of composting for almost 20 years, and I still haven’t hit on perfection. I’ve composted in simple piles, wire cylindrical enclosures, pits, and even a rotary bin (the composter that looks like a garbage can on a spindle). I’ve finally settled on a three-bin system made of wire panels that attach at the corners with pins. On good weeks, this works well and I can gaze at it contentedly. On bad weeks, it looks like someone buried a twin bed in garbage.
I stick with it because I know how wonderful compost is for my garden. It not only feeds my plants, but also greatly improves the texture of my soil, which makes watering, weeding, planting, and fertilizing easier and better. It attracts earthworms, which aerate and fertilize the soil. And it has almost magical properties, containing micronutrients and microbial actions that scientists are still learning about.
Then there’s the issue of waste management. A compost heap keeps grass clippings, leaves, and other biodegradables out of landfills and recycles them into the ultimate earth-friendly byproduct.
I’ve purchased bagged compost, too, and was disappointed. Good compost is black, moist, and crumbly with an indescribable earthy, alive smell. Bad compost may be crumbly, but it’s not always black and it doesn’t have that incredible aroma that means all those magical properties are there. Compost geeks like me call it dead compost.
So it’s worth the time and money to invest in a good composting system. Before you begin, consider these
Location, location, location
The best compost system for you depends on where you garden. If you’ve got 10 acres, hey, knock yourself out. I know gardeners who have six bins, each designed to make individual 3-foot by 3-foot piles—big enough for the pile to retain moisture and heat, but small enough so you can turn it with relative ease. You can cobble together a system like this from free wooden pallets and tuck it behind the barn. With this system, it’s easy to do cold composting (also called passive composting). Simply pile leaves, grass clippings, and other organic yard waste in several of the bins and stockpile finished compost in the others. And if you have more garden materials than you can handle, make one big pile that you can toss into the smaller piles as the larger twigs and leaves break down.
Even in a smaller garden, you may have room for three bins, tucked behind a garage or hidden in a side yard. With three bins, you can put non-decomposed material into two of the bins while you dig out compost from the bottom of another. (The bottom of the heap, the oldest part of the pile, is where all the good black stuff is.) Three bins also hold a considerable amount of material.
In a small city garden or a tiny plot attached to a condo, a single compost heap may be all you need. You can make a container from pallets, stacked concrete blocks, or chicken wire stretched around some stakes driven into the ground. But if you have to look at it every day, you may want to invest in a sleek, tidy commercial unit that hides all those old banana peels and egg shells. These units also keep out mice, which like to burrow in heaps, and rats, which feed on garbage. (Compost heaps also can attract more charming animals, like a Baltimore oriole feeding on the remnants of an orange—or, in my case, a neighborhood golden retriever with an unexplained fondness for watermelon rinds.)
Hot or cold?
The system you choose also depends on whether you want to do cold composting or hot composting. Cold compost rots at a relatively low temperature. It develops after a year or two of collecting leaves, clippings, and other waste and leaving the pile alone. It helps if you add moisture (or protect it from too much moisture) and turn it occasionally, but it will still break down even if you never touch it. Cold composting is sometimes called passive composting.
Hot composting, sometimes called active composting, requires paying attention to the ratio of brown materials (carbon-rich things like autumn leaves and dried-up perennial foliage) and green materials (nitrogen-rich waste such as grass clippings and green foliage). Materials break down quickly—sometimes as fast as three weeks, if you’re good. Hot compost also requires correct moisture levels. You’ll need to keep the compost moist but never soggy, and turn it every few days to mix materials and work in oxygen.
Hot compost can reach a temperature of more than 130°F—it’s uncomfortable to put your hand in the center of the pile—and it kills weed seeds and many disease pathogens lurking in the garden.
Good, hot compost requires enough space to stockpile green and brown materials so you can mix them together in the right ratio. To produce it in large volumes, you’ll probably need a chipper-shredder—a machine about the size of an oversized lawn mower. If you want fast compost, a rotating bin might be a good choice, but you’ll also need an area to stockpile leaves, clippings, and other raw materials.
You can also let worms do your composting (called vermicomposting). To do this, you need to keep a container of specially purchased red wiggler worms (not earthworms from the garden) evenly moist at an even temperature and feed them kitchen and yard waste. The worms don’t produce a lot of compost, but they give you a rich, valuable blend of compost and worm castings for the garden. Vermicomposting takes up little space, so you can compost indoors in a closet or the corner of a heated garage.
The composter you choose also depends on how much material you want to compost. My garden is a typical suburban lot, but it’s full of perennials that need to be cut back every spring. Other gardeners might have mountains of autumn leaves each fall.
I don’t have a chipper-shredder, so after years of struggling to fit all my yard waste into three bins and a few pits, I gave up and had my lawn service haul away a pile of debris as big as my minivan. Now I can focus realistically on composting the more modest amount of debris left.
If you have a very small amount of waste—some grass clippings, two or three bags of autumn leaves, and a steady supply of kitchen waste—a one-bin system will work fine.
Keeping up appearances
Once you’ve decided on the ideal system, it’s time to think about looks. Composting is messy—it’s refuse and waste, after all. If you don’t care what it looks like—or you’ve got a perfect hidden spot somewhere to stash several bins—more power to you.
You can make even the most expansive composting operation attractive with a little determination. My neighbor built a beautifully crafted three-bin system with lattice panels and tucked it in among undulating limestone-edged raised flower beds. In the nearby garage, he stashes a chipper-shredder with wheels.
However, the store-bought, self-contained systems with convenient lids are easier for those of us who are less creative or who have to walk by the compost every time we step out our back door.
Purchased compost systems are not cheap. They start around $25 (for one bin) and can run up to $300 for a more complex system. But when I think about how much I spent for my prized tree peony or the pretty wooden bench by the pond, splurging on a good compost system doesn’t seem out of line. After all, for that $100 or so, I’m feeding my soil, improving my garden, and saving the planet all in one fell swoop. How great is that?
Choosing a composter
Traditional multi-bin system
Ideal for: Gardeners with lots of space who don’t have to worry about the appearance of their compost heap.
Advantages: Can handle lots of plant materials and waste. Ideal for cold composting.
Disadvantages: Takes up a lot of space. With some bins, you have to take them apart to get to the compost on the bottom. Not necessarily attractive.
Cost: Free if you use salvaged materials. Wire bins are about $25 to $50 each. Up to $400 for store-bought all-wood kits with three bins.
Rotating bin system
Ideal for: Dedicated compost junkies who want a constant supply.
Advantages: Eliminates strenuous turning. Can create compost in as little as three weeks. Container helps you control moisture.
Disadvantages: Can’t be used alone—you need a holding area to store raw materials.
Cost: $125 to $300
Enclosed one-bin system
Ideal for: Small-space gardeners
Advantages: Contained, tidy-looking. Usually rodent-proof, depending on design. Container helps control moisture.
Disadvantages: Handles small volume only. Best for cold compost.
Cost: $25 to $175
Wire or flexible plastic cyclinder
Ideal for: Gardeners who like to compost smaller amounts in a variety of spots around the garden
Advantages: Assembles in a snap. Easy to lift to reach compost at the bottom. Portable so you can position in various spots around the garden, such as behind shrubs, for temporary compost piles.
Disadvantages: A bit flimsy; bends and cracks over time. Can tip if not partly buried or anchored.
Cost: $20 to $50
Worm box or bin
Ideal for: Avid composters, especially those in temperate climates who are able to compost outdoors.
Advantages: Can be used indoors or out. Compost includes highly beneficial worm castings.
Disadvantages: Worms must be kept at 50°F to 75°F. If you’re not fond of worms, there’s the “ick” factor. In cold-winter climates, must be done indoors, limiting the amount of compost produced.
Cost: Worms cost around $20. Box or bin is free if made with salvaged materials; otherwise $75 to $300.
Veronica Lorson Fowler is a garden writer in Ames, Iowa.