Leave nature to itself, and decomposition can be a messy, smelly, pest-attracting process. Composting, however, is a different story, one with a much better smelling conclusion. Composting may be a natural breakdown of organic materials, but it's nature accelerated and enhanced. It's a microorganic feast in which just the right conditions and ingredients are combined to help aerobic organisms make efficient work of converting waste into nutrient-rich matter that helps plants grow. In compost pile or bin, kitchen or backyard, composting is easy if you just know how to start. So let's get started!
Compost piles are great if you're composting leaves and yard waste in a DIY wood or wire box. But if you plan to add food wastes to the mix, bins and tumblers make it a lot easier to control the composting environment, including heat, moisture, aeration, and pest deterrence. For homes or apartments lacking yard space, worm composters or kitchen composters can provide an odor-free solution for indoor composting of organics and food waste (our Compost Bin Buying Guide has additional details).
But assuming you already have a bin, where should you begin? In composting, as in real estate, it all starts with location, location, location.
A partially shaded area that gets about a half day or so of direct sunlight is probably a good spot for composting. The ground should be level and well drained. Placing the bin directly on soil (versus asphalt or concrete) assists with aeration and allows microbes, worms, and other beneficial organisms to get inside. Pick a spot that's close enough to your home for easy access, and offers proximity to a water source.
Maintaining a proper balance of carbon and nitrogen is one of the most important keys to composting success. This is known as the C:N ratio, or in home composting terms, browns and greens.
Greens are substances with a high nitrogen value. Uncooked/cooked vegetables and fruit peels, breads and grains, coffee grounds and filters, freshly mowed grass and green leaves, and paper tea bags (don't forget to remove the staple!) are common compost greens. This nitrogen is what gives composting organisms the protein they need to grow and reproduce.
Browns are substances loaded with carbon, which composting organisms use as an energy source. Typical carbon sources include cardboard, paper and newspaper, yard trimmings (leaves, twigs, and branches, not weeds or diseased plants), sawdust pellets or wood chips, egg shells, and even things like wood ash, cotton rags, or dryer lint.
A ratio somewhere between 2:1 and 3:1 browns to greens is a good target for beginners. Avoid adding cooked, greasy, or oily foods to the mix, as well as dairy products. Metal, glass, and plastic should all go in the recycling bin. Pet wastes - excluding hair and fur - are a no-no, as are baby diapers.
Starting a compost bin is a bit like building a layer cake or lasagna with browns and greens (remember your ratios). Start with organic materials until you have about six to eight inches of layering, lightly watering each layer as you go. Putting bulky materials in the first layer will help preserve air space so that aerobic microorganisms can do their work (porous items like wine corks are also great!).
As you go, try to keep a balance of large particles for better aeration and shredded or chopped up particles for faster decomposition. After you've built your layers, add a compost starter on top, and cover it with a final two-inch layer of garden soil or active compost.
If you've made your compost cake well, the organisms that find it delicious will be in full swing in a matter of weeks. The layers will settle and heat up, reaching temperatures between about 110°F and 150°F, ideally. Check with a compost thermometer, and for best results, tumble or aerate the compost if it drops below 110°F, mixing in fresh material and water as necessary.
If the compost smells like rotten eggs, that means too much water and/or not enough air. Add more browns, and tumble/aerate the bin. If it smells like ammonia, there's too much nitrogen or greens. Add coarse browns for balance.
This could be due to insufficient moisture, air, or nitrogen.
Excessive heat can kill off the organisms that make composting happen. If your compost exceeds 160°F, aerate and add more browns.