Thursday, October 11, 2012

Fall and winter gardening under low tunnels

Written by Fran Scher, Master Gardener, Washington County


Low Tunnel with lettuce, beets and kale
Fall is my favorite season–for cooler weather and the tasty fall vegetables in my garden. I’m trying something new this year and thought I’d share my adventure with you. I watched a video recorded by Jon Traunfeld at the University of Maryland about gardening in low tunnels under row cover and became inspired. You can watch the video here. The video focuses on using row cover laid over hoops to create low tunnels for insect control. I also read a book called “Four-Season Harvest” by Eliot Coleman who explains how to grow and harvest food year round, even in Maine! So I decided to give it a try.
I recently put raised beds in my garden, so created tunnels on two of them using 1/2 inch, 8-foot long electrical conduit bent over 18 inch long rebar pieces. I put four hoops in each 10 foot bed.  For the row cover, I started with the lightweight type for insect control, 83 inches wide. It worked out well to twist the cloth together at each end of the bed and hold it down with ground staples. This way, I can simply roll up the cloth on the sides to gain access to the plants (see next photo). I then planted a variety of cold-hardy vegetable varieties, including kale, carrots, bok choy, lettuce, spinach, beets, and green onions.
Low Tunnel with carrots, lettuce, radishes and bok choy
I immediately noticed much less damage from cabbage worms and flea beetles on plants growing in the tunnels than in the rest of my garden. Now that the temperatures are dropping, I have placed a second layer of row cover (heavyweight) over the lightweight type. This way I can remove the heavyweight cover in spring and still have the insect protection of the lightweight cover.
I purchased a new indoor/outdoor thermometer recently and realized that I could buy a separate sensor to put in one of the tunnels. Now I can monitor the temperature in the tunnels anytime, as well as determine the daily minimum and maximum temperatures. As we progress into winter, I don’t know if the heavyweight row cover will protect the plants. I read that the White House gardens grow some crops year round in their plastic-covered low tunnels, so I plan to monitor the temperatures in the tunnels to decide whether plastic is needed over the hoops to provide a warmer environment. I’ll keep you posted!

5 comments:

  1. I want to thank Lena for posting this. One correction--I made an error on the width of the row cover in the post. It is 10 feet wide, not 83 inches. -Fran

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  2. Great story, Fran. You've encouraged me to start thinking very seriously about low-tunnel gardening to extend the season on both ends.

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  3. Hi Fran, I love anything that Eliot Coleman writes! I think your veggies will be fine. I never cover my spinach, bok choy, kale, Brussel Sprouts or cabbage: they seem to do well without any protection. I do cover my lettuce, usually with a double layer of the thinnest floating row cover I have (having two kinds of floating row cover would probably be too confusing). The double layer seems to work just fine. I out straw around my carrots.

    Your system is way more sophisticated than mine. I love your idea of the indoor/outdoor monitor!

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  4. Arrgh! Technology is not my strongpoint! I left a comment on Butch's article that was intended for you (although I did enjoy his post very much). Just wanted to let you know that I am inspired by the low tunnels, and determined to expand my gardening year-round. Maybe I can even figure out how to get that clever thermometer to work :)
    Come visit my efforts at Beyond Back Creek http://www.backcreekdesign.com/
    Comments appreciated!
    Melanie

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