Its not too soon to start warming up to spring gardening

March 03, 2007|By ROB KASPER

This week, as the glaciers deposited in the backyard by the St. Valentine's Day storm began to recede, I got itchy to grow something.

The soil was not quite frozen, not quite thawed. The sun was stronger than it had been during the dim days of February, but it was still far from welcoming. Then there was the wind, raw and biting, great for lifting up kites and knocking down cyclists.

March was teasing. Yesterday, the weather seemed to invite me to scratch the ground, to believe that the grip of winter has loosened. But Thursday, its chill had forced me indoors to page through garden books, to plan and to pine.

One of the books I read was The Victory Garden Companion by Michael Weishan, host of a PBS television show of a similar name. Reading, of course, is dangerous. It gives you ideas. One garden scheme I came across in this book was cooking the soil.

The idea is that you cover the ground with double layers of clear plastic. The sun shines down, the plastic heats up, and the ground gets fried.

Why do you want to fry the soil? To kill verticillium wilt. Verticillium wilt, as many gardeners have discovered, is a fungal disease that causes your tomato and pepper plants to lose their leaves.

Sitting and reading in my living room, I got real worked up about battling wilt. I vowed to stop it, or at least stomp on it, as soon as the weather breaks.

To do this, I need a double layer of 6-millimeter clear plastic sheeting and three pieces of lumber. That is what the book told me. One layer of plastic goes down on the well-watered ground. Two pieces of lumber are placed at the ends of the planting bed. The third piece of lumber goes in the middle of the bed. You stretch the second layer of plastic over the lumber a few inches above the ground layer and pull it tight.

The idea, I gather, is to create a "sandwich" of hot air that will push the ground temperature up to 120 degrees. Six hours at this heat will, Weishan assured, knock verticillium wilt for a loop.

I had a few questions about this procedure. What time of year do you have to do this? Why clear plastic? Wouldn't black plastic heat up faster?

Weishan, in a telephone conversation from his Boston-area home, ticked off the answers.

The best time of year to cook the soil is the summer, when the sun is packing plenty of heat, he said. This would mean I would have to hold off planting anything in that part of the garden until the cooking process had run its course.

Weishan recognized that, after being cooped up all winter, few gardeners could resist the urge to plant every inch of ground in the spring. But he said that is a sacrifice that must be made for the good of the soil.

Clear plastic works better than black plastic, he said, because it allows the sun's rays to penetrate the soil.

He also had a few suggestions of ways to mollify those of us who are filled with pent-up planting urges. "Now is the hour to start your seeds," he said. Get some seeds of vegetables that matter to you, like leeks and heirloom tomatoes, he said. Plant them in a soil-less mix, a blend of peat moss and vermiculite, that along with plastic planting flats, are sold in garden-supply shops.

"Another gizmo that helps a lot is a heating mat. It sits under the flats and starts germination," he said. Put the flats near a window with good sunlight or under fluorescent lights and keep them moist.

But the most important thing a gardener can do at this time of year, Weishan said, is to draw up a plan of what crop goes where.

"I can't get over how many people, even some master gardeners, don't have garden plans," he said.

Having a plan allows you to rotate crops and helps keep your soil free of diseases, he said.

"There is nothing worse than putting all this work in, growing your vegetables from seeds, then having them fail because of something in the soil," he said.

So this weekend, instead of picking up a trowel, I am going to pick up a pencil and paper and start sketching.

"Plan twice, plant once," Weishan advised.

rob.kasper@baltsun.com

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