TAMING THE RAIN
Too much rain has a measurable effect in the garden, not all of it negative. The vegetable garden is the most dynamic corner of the gardening world — where else can you have three gardens in one year? — and it is here that the precipitation has formed a jungle of unrestrained lushness.
In my own little plot, all the cucurbits — zucchini, winter squash and cucumbers — have taken on an extraordinary vigor. The question in wet years is whether the harvest will be insipid because the fruits have had their sugars diluted. This has been the case with some early tomatoes. Others have tasted fine. Continued rain will also bring fruit-splitting. I now harvest tomatoes just this side of green and do the final ripening on the kitchen counter.
Rain brings more work for the gardener, in time spent grooming — removing diseased leaves, cutting back wayward growth, and tying up sprawling tomato and squash vines and leaning dahlias and sunflowers. I find this tidying curiously satisfying. Less appealing is dealing with the constant onslaught of weeds, made worse by the warmth and the rain. Pokeweed, a thug by summer’s end, is already 8 feet tall in untended areas.
Rains that bring flash flooding have the obvious effect of washing things away — new seeds, mulch and the earth itself — but what isn’t as apparent is the way that they beat up the soil. On unprotected beds, a deluge leads to a crust that must be broken up. Or worse, the rain compacts the vital top layer of the soil.
There are a number of ways of protecting the soil, the easiest with a good layer of mulch — in the vegetable beds not with shredded bark, wood or wood chips but a generous blanket of straw. It saves the soil from taking a beating. Mulch also suppresses weeds and conserves soil moisture.
Soil that is made loamy through organic matter is better equipped to handle heavy rain; it acts as a sponge and resists erosion and compaction. Experts say don’t add sand to clay soil because you’ll create something akin to cement. But in my raised beds, I have incorporated generous blends of sharp builder’s sand with leaf mold — supplemented with each new planting — and the results have been good. In a drought, I’d have to water this feverishly.
Another approach is to adopt a no-till method of gardening in which the soil is not seasonally dug and amended, and seeding and planting take place with minimal soil disturbance. The idea is to keep soil microbes intact and to continually add organic matter to the soil surface, to be taken in and broken down by all the creatures that live in the underground biosphere.
Jon Traunfeld, director of the Maryland Home and Garden Information Center, has been trying this approach in a part of his own garden and says it has helped in preventing weed growth and soil compaction. He says, however, that planting into uncultivated soil takes more effort.
Another approach is to plant cover crops, sometimes called green manures, during periods between crops. Common choices include buckwheat, annual rye, hairy vetch and clovers, and they can be used in no-till gardens or in conventional ones.
I’ve thought of these as something to plant in the fall to get your soil through the winter, but at Thomas Jefferson’s Tufton Farm next to Monticello, in Virginia, Keith Nevison likes to sow buckwheat every time a bed is turned over.
He recently sowed buckwheat in beds of newly harvested potatoes, garlic and onions. The plots are earmarked for fall greens in a month or so, when the quick-sprouting buckwheat will be chopped and worked into the soil. The buckwheat will replenish the phosphorus lost with historical tobacco farming. “We strive never to have a vacuum,” he said.
The paths around the beds, which would be a sloppy mess this year if left bare, are planted with a tough perennial cover crop named New Zealand white clover. It has endured the pounding of both raindrops and human feet. “There’s been very few weeds, and it has allowed us to give numerous tours,” he said.
And speaking of tours, I asked Luis Marmol at Dumbarton Oaks to show me the resplendent vegetable garden at the historic estate and academic center in Washington. Where my three lone mature and headed cabbage plants had rotted away in July, Marmol’s potager was brimming with pristine redleafed and crinkly savoy cabbages, and the unlikely geranium border plants had performed beautifully.
His layout and plant selection this season were inspired by the Potager du Roi near the Palace of Versailles.
He attributed the vigor and health of the plants in the summer garden to its location: open and sunny with good air circulation, and a slight tilt to the ground plane that allowed measured drainage. There was, however, one glaring omission: not a single tomato plant.
“Too many diseases,” he said as he handed me a fat, watery cucumber.
Gardening tip: If latesummer lawn renovation is in your future, the work can be made easier and more evenly paced by dethatching lawn areas over the next few weekends in advance of seeding. Use a dethatching rake. Removing built-up thatch will give seed the soil contact it needs to germinate.
Cabbages are at home in cool, Northern gardens, but an open, sunny location helps them in warm, humid locations.
You can protect your soil easily with a good layer of mulch. A blanket of straw will do for your vegetable garden.