by Amira Adarkwah
Composting has many benefits for both you and the environment. It enriches the soil, helping it retain moisture and suppress plant diseases and pests. Composting can keep as much as 30% of waste from being thrown in your trash can. This reduces the amount of trash in your home and the need to buy trash bags or to take out the trash as often. Additionally, composting keeps landfills from filling up prematurely with organic material that can decompose. It reduces methane emissions, lowering your carbon footprint, and anaerobic composting, in particular, can even be used to capture methane to fuel cars, trucks, and buses.
The Process and Chemistry of Composting
Composting is the digestion of organic and nitrogenous materials by microbes into simpler components, which can then fertilize soil. There are two types of composting: aerobic (which requires oxygen) and anaerobic (which doesn’t require oxygen). Unlike anaerobic composting, aerobic composting doesn’t require expensive equipment.
Aerobic composting occurs in an open system. Two types of bacteria—mesophilic and thermophilic— usually present in organic waste are involved in the process. Mesophilic bacteria thrive in moderate temperatures, typically between 20°C and 45°C, while thermophilic bacteria grow best in higher temperatures, usually between 40°C and 65°C.
One reaction that takes place during aerobic composting is the oxidation of glucose (C6H12O6), a monosaccharide (simple sugar) present in plants. Another important factor in this process is the carbon to nitrogen ratio. Living organisms generally need about 25 times as much carbon as nitrogen. The final products of aerobic composting are carbon dioxide, water, and a dark-brown or black organic material. This material, known as compost, will be only about half of the weight and half the volume of the original material. Depending on the size of the compost pile, what you put in it, and how frequent you turn it, the process can take from three months to two years.
How to Compost
There are several different ways to make a compost pile. To start a compost pile in your backyard, choose a dry, shady spot near a water source for your compost pile or bin. Add equal amounts of brown (dead leaves, branches, twigs) and green (grass clippings, vegetable waste, fruit scraps, coffee grounds) materials. Ensure that larger pieces are chopped or shredded and moisten any dry materials as they are added. Alternate layers of organic materials of different-sized particles. Once your compost pile has is established, mix in grass clippings and green waste and bury fruit and vegetable waste under 10 inches of compost material. Cover the top of the compost with a tarp to keep it moist. Give the pile a quick turn with a pitchfork or shovel every few weeks to aerate it. When the material at the bottom is dark and rich in color, your compost is ready to use.
You don’t need to have a backyard to compost. Composting can be done indoors, too, using a special type of bin, which you can buy at a hardware store, gardening supplies store, or even make yourself. A properly managed compost bin won’t smell or attract pests or rodents.
What to Compost and What Not to Compost
Here is a list of some of the items that you CAN add to your composting pile:
Fruits and vegetables
Eggshells
Coffee grounds and filters
Teabags
Nutshells
Shredded newspaper
Cardboard
Paper
Yard trimmings
Grass clippings
Houseplants
Hay and straw
Leaves
Sawdust
Wood chips
Cotton and Wool rags
Dryer and vacuum cleaner lint
Hair and fur
Fireplace ashes
Here is a list of things that you should NOT add to your composting pile (and why):
Black walnut tree leaves or twigs- release substances that might be harmful to plants
Coal or charcoal ash- might contain substances harmful to plants
Dairy products and eggs- odor problems/ attract pests
Diseased or insect-ridden plants- diseases or insects might survive and be transferred back to other plants
Fats, grease, lard, or oils- odor problems/ attract pests
Meat or fish bones and scraps- odor problems/ attract pests
Pet wastes (e.g., feces, cat litter)- might contain parasites, bacteria, germs, pathogens, and viruses harmful to humans
Yard trimmings treated with chemical pesticides- might kill beneficial composting organisms
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