Soil is the foundation of the garden. It supports plant growth by providing stability, oxygen, water, temperature modification and nutrients. In fact, improving your garden’s soil might be the single most important thing you can do to set yourself up for success.
So how can you improve your garden’s soil? The answer is composting. By accelerating this natural process, you can transform your food scraps and yard waste into a high-quality soil amendment for your garden. Compost improves soil structure, increases its ability to retain water, increases aeration and improves soil fertility. You’ll also be saving space in landfills since food waste is the No. 1 item disposed of in our nation’s landfills.
Despite the rumors you may have heard, composting isn’t difficult. You first need to determine what method of composting is best for you. Common methods include: holding units, turning units, heaps and trench composting. There’s even vermicomposting, which harnesses the digestive power of worms. I’m going to focus on holding units and turning units, since I use both.
Holding units do exactly what the name implies. They require very little maintenance, and some are compact enough to be used on apartment balconies. Non-woody yard waste and food scraps can be added as they are generated. It is one of the easiest methods to use since no turning is required but the lack of aeration makes the process slower. Many of the commercial one-bin systems sold in stores and online are holding units.
Turning units work faster because the turning process introduces oxygen needed by aerobic bacteria. There are generally two types of turning units: a series of bins or a rotating barrel known as a tumbler. Turning systems typically cost more and require greater effort to build but have the advantage of providing compost more quickly and getting hotter, which can help kill pathogens and weed seeds. Turning units differ from holding units in that you will need to stop adding material to allow the batch to complete the decomposition process.
Now you know some basic methods, we can move on to what to compost. You can add anything that is derived from plants such as potato skins, celery and broccoli trimmings, leaves from the tops of strawberries, greens from your turnips if you don’t eat them, etc. You can even compost coffee grounds, egg shells, tea bags, newspaper and cardboard. Leaves, grass clippings, stray/hay and wood chips from the yard also can be composted.
We can maximize the rate of decomposition by creating the proper balance of carbon-containing materials, called "the browns," and nitrogen-containing materials called the greens. Aim for 2-parts green to 1-part brown.
You can think of brown materials as being dry. Examples of brown materials include leaves, stray/hay, wood chips and paper. Green materials are generally fresh and wet like fruit and vegetable scraps, coffee grounds and teabags. Eggshells, though not derived from a plant, can be composted and are considered a green material. The smaller the materials, the faster it will break down.
I find that convenience is the key for composting. There are many containers available for storing kitchen scraps until you are ready to bring them outside. Commercially available containers are available with filters to help absorb odors. An old plastic ice cream bucket with a lid works just as well.
Be sure to avoid meat, dairy, oils/grease or animal waste. It’s probably best to avoid composting weeds and diseased plant materials unless you’re carefully monitoring the temperature to ensure it is hot enough to kill weed seeds and pathogens.
There are a few other things to think about when it comes to composting. The compost should be moist but not soggy, like a wrung-out sponge. Depending on the system you are using, you may need to add water to your pile to achieve the proper moisture level. If you can’t walk by your compost without holding your nose, it’s probably too wet.
Aeration is important, too, especially in turning-unit systems. Those microbes that are doing the work of breaking down the materials need oxygen. Turned system compost piles should be turned at least once a week. You’ll know your compost is ready to be used when it no longer looks like the original ingredients, called the parent material. It should be dark and crumbly, like nice, rich soil.
People often feel stressed about getting everything right. Unless you have a timeline, don’t stress about it. If the carbon-to-nitrogen ratio isn’t exactly right, it will just take longer to get the finished product.
For more information, visit the S.C. Department of Health and Environmental Control's website, scdhec.gov/environment/recycling-waste-reduction/composting-recycling-naturally.