Early spring planting and fall gardening can be a challenge. Fortunately , there are ways to extend your season in early spring and fall/winter. When many gardeners still have their feet up and reading, you can get the jump on your spring garden with a low tunnel and when most producers roll up the garden after the first frost you can extend your season into the winter as well with low tunnels.
Low Tunnels used in high tunnels to protect young plants from cold nights.
Low tunnels, also known as quick hoops, are made of 10-ft. galvanized electrical conduit that is bent into 6-ft. diameter half circles. The ends of the hoops are stuck in to the ground 6 to 12 in. on each side and then covered with either a floating row cover or plastic.
Like a temporary micro-greenhouse – which allows growing food and flower crops throughout the winter, it will also allows gardeners to start more crops in trays .
Beets, carrots, spinach, arugula, and kale under the covers may thrive until late December and January. At that point, you may have rips in your cloth or plastic. Keeping covers tight and well anchored are key to avoiding rips, but once one starts, it’s impossible to stop it.
- 3 x 10′ lengths of electrical conduit
- A low-hoop bender
- 8 x 2′ rebar stakes
- A sheet of greenhouse plastic, 10′ long and 10′ wide (check your local garden supply store)
- A big ball o’ twine
- A hammer
You will need a hoop bender. This is available through Johnny’s Select Seeds. It will run you about $59 and will be your most expensive part. The bender comes with great instructions.
Mark 6 small holes in the ground where each end of the three hoops will sit on its own rebar stake. The holes should be 2.5 feet apart on the length of the tunnel, and 4 feet across from one another. For longer tunnels, it’s recommended that you space hoops about 5 – 7 feet apart.
Hammer Your Rebar into the Ground
Now that you have your holes outlined, pound your rebar into your outlined holes with your hammer, each about halfway into the ground. Your hoops should be 2.5 feet apart from one another, and 4 feet across if your tunnel is 6′ or less, 5-7 ft across if longer.
Tie an Anchor
Take a small piece of twine and tie a small loop around the middle of each rebar stake. You want the loop to be able to rest loosely at ground level. These small loops will serve as anchors when you tie down your plastic.
Put Your Hoops in Place
Put your hoops in place by sliding them on top of the rebar until they hit the ground. You now have the skeleton of your low tunnel greenhouse.
Tie a Ridgeline
Create a ridgeline by tying one long length of twine to the top center of each hoop. Make sure your line is taut. This ridgeline will link the tops of your hoops together and help support your plastic when you drape it over the structure.
Stretch your plastic over the hoops and twine, making sure it’s even on all sides. On the two long sides of the structure your plastic should just reach the ground, but on the front and back end you will have a few extra feet.
Tie Down the Ends
Grab your two remaining rebar stakes. One will be used at the front of the tunnel and one at the back. Stand at the front of the tunnel, facing the first hoop, looking down the length of the tunnel. The extra plastic on this end should be gathered just in front of your feet. Now step back about two feet from the hoop and pound your rebar stake halfway into the ground, centered in the middle of the hoop but a few feet out from it, and angled slightly away from the tunnel. Next, take a length of twine and tightly tie the top center of the hoop (right where your ridgeline ends) to the bottom of your newly placed rebar stake, pulling it tight to hold the end of your tunnel in place . An even sturdier option would be to use a wire and tension bolt kit for this step. You can then gather the extra plastic, twist it a bit, loop it around the rebar (sitting on top of the twine you just tied) and tie it in place with some twine. Repeat this whole process on the back end of the tunnel.
Tie Down the Plastic of the Low Tunnel Greenhouse
There are many ways to do this and you should feel free to create your own. This is the method I learned and it works best with a partner. The basic concept is to have you and your partner stand on either side of the hoop and essentially toss the twine back and forth over the top of the tunnel and then pass the twine through those small anchor loops you tied around each rebar stake. Refer to my pictures to get a sense of the pattern I’m describing. For a more in-depth explanation of my method, please see the excerpt at the end of this post.
Harvesting from a low tunnel is not as convenient as harvesting from a greenhouse or high tunnel, as it’s usually quite muddy and cold in the field, but the cost of a low tunnel is so much less, it’s worth it. If you find that you are serious about extending your seasons, you may want to investigate high tunnels.