Standing in a garden on a warm sunny day, watching cream-colored butterflies flutter among the tidy plots of vegetables, listening to the buzz and whir of hover-flies and bees, I wasn’t really thinking of Tennyson’s “nature red in tooth and claw.” But I was touring Seattle Tilth’s demonstration garden, and tour leader Amy Ockerlander was just then telling us about watching a centipede cut up a cabbage worm and eat it. How can you raise the odds that you’ll have a hungry centipede patrolling your garden patch? We were there to see how Tilth harnesses natural processes to grow healthy vegetables in sustainable ways.
Big message number one was start with mulch. (That’s Amy by the huge pile of it.) Especially in a climate like ours, where it rains all winter long and then in summer (usually!) rains hardly at all, mulch soaks up moisture, keeps nutrients from being washed away, and suppresses weeds that fight your veg for nutrients. Plus it provides a happy home for critters like centipedes, spiders, and other helpful killers. You can also protect your soil by putting down a layer of feed bags (especially effective over the winter here to keep soil dry-ish). This is Seattle, so of course we go for coffee-bean bags!
Mulch was only one “layer” strategy we talked about. Those cream-colored butterflies?–As they flutter prettily from plant to plant they are laying hundreds of dot-sized eggs on your cabbage-family plants that hatch into voracious bright green cabbage worms. One way to mess them up is to put in a physical barrier–cover the plants with row cover, a light cloth sheet that keeps the butterflies from sticking their eggs to the leaves.
In following the “layer” strategy, you don’t always have to put the layer on top. In “hugelkultur,” the raised garden bed starts with a layer of rotting wood (chips, twigs, sticks, branches . . .) at the bottom. Then you mound the soil on top. Think of the wood as a “nurse log” for your plant, sponging up water and nutrients that otherwise would leach away.
To thrive, your garden also needs pollinator insects like mason bees. The Tilth gardeners have constructed mason bee “blocks,” little bee condominiums, under the eaves of the building, so that the bees can over-winter and re-populate year after year. And to attract pollinators, the garden has flowering ornamentals planted among the vegetables.
Some plants naturally thrive when planted together, like the “three sisters” in Mexican farming: corn, squash, and beans. (Normally, the corn would be close to eight feet tall!–but here in Seattle, it’s lucky to hit five feet.) The corn provides a trellis for the beans to climb up, and the squash shades the roots of the other “sisters.”
Big message number two was keep your resources where you use them. They use a rain garden to manage the rainfall runoff from the building–about 20,000 gallons of it in a typical year! (This is water that isn‘t going into the sewer system, to be processed and then bought back from the city to water the garden. That’s a long round trip to water that veg patch over there!) Pipes capture the water and feed it to a narrow trickle of rock-lined stream bed that delivers it to a bowl-shaped depression about five feet across. The thick plantings hold it there until it soaks out to the surrounding area. They also use compost “digesters” to break down plant trimmings into nutrients that leak out of the bottom into the surrounding soil to be taken up by the next-door-neighbor plants.
Amy described the whole sustainable gardening endeavor as “bringing life into the garden.” I loved to hear how cleverly these master gardeners wove together and managed the thrust of life in soil, plants, insects, light, and water to make a healthy, bountiful harvest. But for me, it is also a sustaining pleasure to see the order and grace of their well-tended garden–to sit on a lovely trellis bench and gaze at the garden, to admire a fragrant stand of basil corralled by an artful soldiering of bamboo stakes, to imagine beans scrambling up the string trellis behind the lettuces in their hoop pergolas. I love these minutely tended plots that speak so eloquently about the diligence and hopes of the people who built them!