For Kim Lefler, Harbor Island resident and organizer of the Lefler Communal Garden on Wrightsville Avenue, gardening is a cyclical process. From seed to scrap, everything is used and everything is valuable, especially what she calls black gold: dark, dense organic soil harvested from the garden’s compost bins.
“It’s so dense and so rich and it’s so easy,” Lefler said. “It’s wild to think, instead of throwing away your eggshells and your coffee grinds and your fruit and vegetable peelings, you put it in a bucket and empty the bucket in the ground in a covered space. You introduce paper to it and water if it’s dry. You toss it and toss it and let the sun break it down, and in a period of time you have this amazing food for your garden beds.”
Any experienced local gardener knows the need for enriched soil. Susan Brown, horticulture agent with the New Hanover County Cooperative Extension Service, suggested composting as the easiest solution to the biggest obstacle gardeners face in a region covered in sandy soil.
“That’s really the key for being successful, especially when you’re growing food. You have to continually enrich your soil,” Brown said. “I very rarely, if ever, plant something without amending the soil because in my experience, the plants do not live. They cannot hold the moisture.”
Organic material can be purchased at garden supply stores but Brown and Evan Folds, of Progressive Gardens, warn against commercial compost. Folds said he regularly tests commercial compost and finds it is mulch or aged manure. Brown said compost imported from poultry producers can contain steroids fed to the birds.
What makes the stuff harvested from table scraps and shredded paper better is millions of microscopic organisms, which make the difference by transforming scraps into a form accessible by plants and trees, Folds said.
“Without those microbes physically present, you can’t make compost. The best you can do is make mulch. That’s what most people end up doing,” Folds said.
Microbes occur naturally but construction and land development often deplete them, eliminating the base trophic level needed for biologically diverse soil.
“The point of composting is to create a biological scenario that takes over for the humus. You don’t have to fertilize a forest and it grows huge trees because the soil is 100 years biologically mature and it hasn’t been denatured by development and artificial processes,” Folds said.
Anybody interested in putting Folds’ theory to the test can acquire five free one-gallon jugs of brown liquid steeped with microbes at Progressive Gardens after signing up to receive the business’ monthly newsletter. He said the process is practically foolproof once a pile is inoculated with microbes.
“Adding those microbes is the fundamental process. From there, it’s just about turning it to keep it up, balancing the carbon to nitrogen ratio, things of that nature,” Folds said.
Turning the pile at least once a week incorporates new organic matter and also infuses the pile with oxygen, allowing the microbes to breathe.
Microbes need a certain proportion of carbon to nitrogen for optimal performance. Carbon and nitrogen are commonly understood as browns and greens: browns include carbon-rich materials like paper, wood chips, straw, and dead leaves while greens include nitrogen-rich materials like kitchen scraps and fresh grass clippings.
“It’s a simplified process that involves carbon for energy and nitrogen for reproduction. So you want about a 2-to-1 ratio volume of carbon to nitrogen. If you have that proper 2-to-1 ratio, what you’ve done is created an ideal environment for microbes to be able to eat and reproduce at a high level,” Folds said.
Brown said invasive plants, weeds and poisonous plants like oleander should not be incorporated into compost piles. Likewise, lawn clippings treated with herbicides or pesticides are best avoided. No meat or dairy should be incorporated into a compost pile. Eggshells can be incorporated, but not the eggs.
Another necessary condition is heat.
“You want it to reach a specific temperature, which is over 100 degrees, because you’re trying to kill any pathogens in there, any weeds, seeds, anything that may germinate,” Brown said.
Compost piles are typically started in spring and summer to take advantage of seasonal heat, and while microbes do slow down in the winter, a pile can be successfully started any time of year.
“The heat comes from the activity of the microbes. It’s not from the ambient heat of the sun or anything like that. You can have a steaming compost in the winter if you have it inoculated [with microbes]because the activity of the life in that pile is what generates it,” Folds said.
For the best results, Folds recommended a pile at least three feet wide and three feet deep to achieve the density needed to generate heat in the middle.
Depending on the size of the material added and the activity of the microbes, it can take two months to a year to produce the dark, crumbly humus desired. Some composters use multiple piles or bins to have the product available year-round.