As a rule, truck drivers aren’t celebrated for their composting acumen. But the owner-operators of New York City’s Compass Green truck, Justin Cutter and Nick Runkle, are the rare (or, possibly, only) exceptions. In a city known better for its graffiti-coated, exhaust-spewing gas-guzzlers, their vehicle is a traveling beacon of greenovation.
The two shaggy-haired 20somethings converted the truck, acquired from a friend in Brooklyn, into a mobile nursery back in 2011, turning the back into a greenhouse and altering the diesel engine to run on vegetable oil. Since then, they’ve been hitting the road each spring and summer to visit inner-city schools, music festivals, protest marches and universities to teach people about sustainable agriculture—including composting.
Turns out people have plenty to learn. “They just take their kitchen scraps and they throw it out the door into a pile, and then they get rats or maggots,” Runkle tells TakePart. Apparently, a lot of folks think composting means dumping a bunch of banana peels and rotten tomatoes into a heap and walking away. “That’s a common misconception,” says Runkle.
So what does composting at home entail? For starters, you need plenty of “dead, carbonaceous material” along with your kitchen scraps, Runkle explains. Dead leaves, corn husks, fibrous plant stalks, “anything that’s dead, anything that’s in your backyard that looks dead and at one point was alive.”
The next ingredient, one commonly overlooked, is soil itself, which contains the living microbes that initiate the process of decomposition. “There’s all of this natural material in dirt, all of the alive little microbes. It basically gives the compost pile the intelligence to know what it’s supposed to do,” Runkle says.
As for proportions, it depends on the venue. On the truck, where space and airflow—which keeps the pile from stinking too much—are at a premium, Runkle and Cutter tend to add more dry material, which creates a slower, cooler decomposition. But for a backyard operation, Runkle suggests a medium-heat pile comprising 45 percent scraps, 45 percent dead material, and 10 percent dirt (and maybe a touch of urine too?).
Though it’s tempting to up the amount of scraps—creating what’s known as “hot compost”—to speed up the decomposition process, Runkle counsels against it.
“The thing about hot compost—and why in organic farming cold compost is preferable—is that…you’re killing a lot of those microbes. You’re going to have much better, rich, fertile compost with a slower pile.”
Runkle advises layering on the three components as you build your pile—which can be housed in a specially made plastic bin, a cube slapped together from scrap wood, or even an augmented trash can—adding a bit of dry material and dirt each time you toss in scraps.
But remember, in addition to those three elements, compost requires an essential fourth ingredient: time.
“At some point, you’re going to need to stop and let that compost pile do its thing,” Runkle advises. “If you keep adding to it and adding to it, you’re going to maybe have some compost at the bottom, but you’ll have eggshells at the top.”
So let it sit. And, after six weeks, turn it over, getting the stuff on the inside to the outside and vice versa. Give it another six weeks to continue rotting and you should have a pile of naturally nitrogen-rich fertilizer ready to apply to your garden.
Can you overdo it? Not according to Runkle, who points out that compost is useful at every stage of planting, from the mix you start your seeds in to the ground you transplant to. “There’s no such thing as too much compost,” Runkle laughs.