Fall has come upon us in short bursts of cold days followed by a few days of warm sunny weather. September was a dry month, but October has provided us with many needed inches of rain. Build It Up has been preparing our gardens for the colder days and nights in East TN with low tunnels. We purchased a hoop bender from Johnny’s Select Seeds for about $70. This nifty device is screwed onto a heavy bench or picnic table and used to bend 10’ sections of EMT (electrical conduit) into 4’ tall hoops. These hoops are sturdy and long lasting, and we feel the investment in season extension is worth the small extra cost of buying metal pipes instead of PVC.
Mary Beth and Kay bending conduit into hoops for low tunnels.
The tunnels are constructed by inserting the hoops about 10” into the ground every 5-6 feet along your row. They are covered with either greenhouse plastic or row cover, which is attached to the hoops by special clips. Our plastic is 4 mil and rated for a minimum of 4 years of UV exposure. Don’t use regular hardware plastic! It will degrade quickly in sunlight. If you are using row cover, look for something rated for winter protection. Some lighter row cover is great during the summer to prevent insects from getting on your plants, but you’ll want a thicker grade for frost protection. We purchased rolls of Agribon+ 30 cloth, which should be sufficient for most central Appalachian winters. If you are expecting a spell of sub-zero weather (rare, but it does happen!) you can combine the plastic over the hoops with the row cover underneath laying directly on the plants.
A demo low tunnel constructed at Lexy’s garden.
With the low tunnels, you can keep summer plants alive into November or later if the weather remains mild. Cold hardy crops like lettuce, brassicas, beets, chards, spinach and other greens can be kept alive through to the spring. Mid-December through Mid-January, daylight drops below 10 hours per day, which means there isn’t enough light for plant growth. Your plants will hang out until the end of January, but then they’ll pick up growing again into the spring. This is important, because you need to time planting so that plants are mature by early December. Check out the “days to maturity” on your seed packet and count back from December 10 to find the last day you can start seed.
Sides can be raised and lowered to accommodate fluctuating temps.
Come February, our gardeners will be able to start their spring crops with no fear of the cold weather. With these hoops in place, we’ll be able to start summer crops up to 6 weeks earlier and when summer arrives, we’ll use them for insect barrier.
We didn’t provide enough low tunnel materials to fully cover everyone’s garden. Uncovered space was filled with garlic or cover crop. We purchased a fall soil building mix that contains tricale, rye grass, red clover, vetch and daikon radish. After our workshop on no-till soil building, we are hopeful that this mix will work some miracles on our clay soils!
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