Compost piles have been a staple of gardening since Adam was handed that accursed apple, but compost itself takes many forms.
It might be a pile of windblown leaves, trapped in the ankles of a shrub to rot away over the winter with no help from the gardener whatsoever.
At the other end rests the large-scale commercial composting operation, which requires land, equipment, labor and a large, steady stream of raw materials.
What most gardeners discover in time is that there are two basic types of compost piles. In the first, the keen novice spends much effort assembling a bin of just the right proportions and then feeds it grass clippings, old cabbage leaves collected from the neighbors and other organic waste that will achieve the prescribed ratio of 30 parts carbon to one part nitrogen. The perfectionist monitors the moisture level, turns the pile as needed (when ambient temperatures aren’t too cold) and acquires a compost thermometer to gauge the pile’s vitality.
Then there’s the rest of us, who start off with lofty ideas about tending a "hot" pile but end up simply dumping material in a bin or a free-standing pile and getting on with our lives. This produces a cold pile, which decays at its own pace and comes with a couple of disadvantages. The first is that it may take a year to get compost that you can use as a soil amendment or for top-dressing beds and lawns. The other is that its lack of heat means that weed seeds survive, and you can end up salting your entire yard with devilish plants.
If I think compost is weedy, I’ll bury it in vegetable beds or at the bottom of containers.
If you had the foresight to gather, shred and stockpile leaves last fall, you can enliven the pile with all those grass clippings that the spring lawn is about to generate. Make sure you mix them thoroughly into the pile, and give it a watering. Waterlogged piles will go pungently anaerobic, at which point you must board up the home and flee to the hills. But a pile that dries out will mummify and need kick-starting with fresh material and a soaking.
Why do we need compost?
Beyond physically improving the water- and oxygen-holding capacities of the soil, compost contains a galaxy of beneficial bacteria and fungi. Once in the soil, these microbes make plants healthier and more vigorous, trees among them. Achieving all this while you’re keeping yard waste on your site is an obvious plus.
Gardeners are getting the message that this soil biology is important in their plant beds. What isn’t so obvious is that – in a season when everyone is spreading, collectively, tons of synthetic fertilizer and herbicides on their lawn – a top dressing of compost might be a better way to go. Compost in itself is not a fertilizer, but it will feed the microbial web that indirectly makes for healthier grass. Conversely, synthetic fertilizers and fungicides degrade soil structure and harm the soil biology, according to organic lawn gurus.
One true believer is Sandy Lerner, the Silicon Valley entrepreneur turned organic farmer in Upperville, Virgina, who makes and spreads compost by the boatload. The finished product is laid on the livestock pastures that define her 800-acre Ayrshire Farm. The grass is more vigorous, better at crowding out weeds, and loaded with the natural nutrients needed by her animals. "We are basically grass farmers," Lerner said.
Lerner co-founded Cisco Systems and later created the cosmetics line Urban Decay. But she moved to Virginia hunt country in the 1990s and has been organically raising rare breeds of cattle and swine along with chickens and turkeys. Her story has been told in these pages and others. But what isn’t as well known is her devotion to compost.
I met her recently with her farm manager Chris Damewood in a clearing of four acres where row upon row of aging compost – windrows – formed dark-brown stripes encircled with hills of more compost. I counted 25 rows each about 200 feet long, but Damewood told me that at peak production, he has 40 rows extending to 275 feet. Each is about five feet high and turned mechanically five times a fortnight. "The temperatures will get up to 165 degrees," he said, "but we don’t want it to get too high. If it gets above 170 degrees, you can get a fire within."
The heat is the natural byproduct of microbes at work converting raw materials into crumbly, dark, loamlike organic matter. It’s a phenomenon that never seems to stray far from alchemy, no matter how many years you have gardened.
The heat takes care of any nasty germs. "It’s enough to kill off pathogens," Lerner said. "One hundred and sixty degrees is the temperature restaurants use to wash dishes." To prove the point, she leads me to one of the far mounds, maybe 15 feet high, and we clamber up and dig around for worms. In spite of the cold, the compost is home to countless red wigglers.
Deep in my heart, these mounds of black gold provoke a little compost envy, but I tell myself that Lerner has what I don’t have – a legion of livestock to fuel the operation, not to mention the vegetable waste generated by the farm and four satellite farms, and the arrival of manure and bedding from 20 surrounding horse farms.
Unused parts of slaughtered animals add their own nutrients, and before the age of synthetic fertilizers, farmers and gardeners used blood meal as a nitrogen fertilizer and feeds made from "hoof and horn." About a dozen cattle – from a herd of 1,800 – are slaughtered weekly to provide the farm’s grass-fed beef.
The farm generates as much as 1,500 cubic yards of compost annually, Damewood said.
A portion of it is sold, either hauled in bulk to customers or bagged and sold at Lerner’s restaurant and market in Marshall, Virginia, called Gentle Harvest.
Making mountains of compost seems such an incongruous pursuit for someone who helped launch the digital revolution. But Lerner says she grew up on an orchard farm in Northern California. (And if you enter farming, it helps to have an analytical mind.)
Lerner, an avowed Anglophile, said she decided to come to Virginia because of its links – visual and cultural – to the motherland. "The Southern ways are the closest we get to England," she said.
– – –
Tip of the week
Spring rains cause bare soil to crust, making it difficult for vegetable seeds to germinate and grow. This is a problem in particular for carrot seeds. The problem is avoided by backfilling the seed row with sand or a seed-starting soil mix. Make sure seeds don’t dry out.