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Archive for Thursday, April 11, 2013

Garden Calendar: Low tunnels help produce early crop

April 11, 2013

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Jan Butin tends a patch of garden space April 4 at the community garden at 1313 Pennsylvania St. Butin has used a low tunnel to harvest lettuce, spinach, kale, radishes and other cool-season vegetables for the last three to four months.

Jan Butin tends a patch of garden space April 4 at the community garden at 1313 Pennsylvania St. Butin has used a low tunnel to harvest lettuce, spinach, kale, radishes and other cool-season vegetables for the last three to four months.

While most gardeners are planting their early-season veggies and preparing the soil for later crops, one Lawrence gardener is already reaping the rewards of her labor. Jan Butin, who gardens in one of the Common Ground Community Gardens in East Lawrence, built what horticulturists refer to as low tunnels.

She has been harvesting lettuce, spinach, kale, radishes and other cool-season vegetables for the last three to four months. All it took was a little row cover, clear plastic sheeting, wire and some attention to the weather.

Butin, who is also an Extension Master Gardener volunteer, says she learned the basics at a seminar at the state Master Gardener conference a few years ago. The speaker was following the concepts laid out by Eliot Coleman, a market farmer in New York, who has written four books about winter/four-season gardening. Kansas weather is a little different than New York, however, and one of the biggest challenges is keeping the crops from getting too warm on the mild days of a Kansas winter.

“I had to open up the ends for ventilation,” Butin said. “Most of the time I could do it in the morning before work when I knew it was going to be warm. A few times I came home on my lunch break.”

Her reference to “opening up the ends” simply meant lifting the plastic. On really warm days, she would pull the plastic back completely. To give you a better picture, the row cover is laid directly over the top of the vegetables, and the clear plastic sheeting is suspended with wire hoops to make a sort of miniature hoophouse.

The producer Butin learned from recommends a medium-weight row cover. Row cover is available at many garden centers and looks like thin cloth. For the plastic sheeting, 6 mil is the recommended weight. Nine-gauge chain-link fence wire is available in rolls and will work well to create the hoops. You might also need a tool to cut the wire.

Butin says she hoped to make more substantial hoops out of electrical conduit instead of the wire, but the conduit takes more work to bend than the wire.

“It held up pretty well, really,” she says. “And we had a lot of snow this year.”

Butin also notes the importance of good soil preparation. She used compost from the city of Lawrence’s yard waste recycling program, compost from her own yard, and composted cow manure to build her soil quality prior to planting. Because the area had poor drainage, she built three raised rows in which to plant. The row that housed Butin’s low tunnel this winter produced summer crops before she planted the additional vegetables in the fall.

At planting time, Butin selected a few crops she knew she liked and a few that she knew were supposed to be very winter hardy. Her list included black-seed simpson lettuce, Siberian kale, spinach, onion sets, broccoli raab, radishes, arugula and Asian mustard greens. She planted the hardiest crops closest to the ends of the tunnel because they would be more exposed when the ends of the tunnel were opened for ventilation.

For planting time, the soil just needs to warm enough for the seeds to germinate and the roots to start growing.

“I planted over a period of about three weeks,” Butin said, “and then put the row cover on right away.”

Watering is the other concern. Rain will pass through the row cover but crops have to be watered when the plastic is in place. Butin said she watered her crops on nice days when she had the plastic pulled back; about once per week over the winter. This also coincided with thinning, harvesting and weeding.

“It is just really amazing when you get all of this in the middle of winter,” Butin said.

— Jennifer Smith is the Horticulture Extension Agent for K-State Research and Extension in Douglas County. Contact her or an Extension Master Gardener with you gardening questions at 843-7058 or mastergardener@douglas-county.com.

Comments

Don Radina 1 year ago

I put 6 of these tunnels in my backyard and had veggies all winter long. The top was 1/2" pvc water pipe hoops covered with special greenhouse plastic remnants, while the inner layer was row cover on wire hoops. Having the tunnels in the back yard helped a lot with watering and ventilation. I also put little portable heaters in some of the tunnels to keep the temperature above freezing, which allowed me to grow a much wider selection of crops. It was great picking salad, stir-fry, and soup vegetables from under 12" of snow.

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