How to Build a Low Tunnel to Protect Plants from Frost


We’re always talking about extending your growing season with floating row covers, low tunnels, and hoop houses. These all protect your plants from frost.

Today we’ll give you easy instructions on how to build a low tunnel with PVC pipe and floating row cover.

First, watch Tricia build a low tunnel (also called a low hoop house) over one of her raised beds.

Quick review of floating row cover for frost protection

Row covers are made of lightweight fabrics (that “float” on the top of your crops) and they allow sunlight, air, and water to pass through to your plants.

Use our guidelines to choose the row cover weight you need in your climate.

Low tunnels of floating row cover give easy access to your crops, while protecting your plants from frost

Make gardening simpler for yourself when you stretch row cover over semicircular hoops to make low tunnels.  The support of the hoops keeps snowy row cover weight off your plants, and allows you to quickly lift the row cover for harvesting. Instead of using Agribon floating rowcover, you could also use the durable and long lasting Dio-Betalon PVA Film.

Once you have the hoops in place, there are other things you can do… make a small greenhouse by covering with the clear Tufflite plastic. In the summer cover it with shade cloth to cool down your plants and prevent sun burn.

How to build the frame of a low hoop tunnel for a bed 3-5 feet wide


Per each five feet of tunnel:

2 18” pieces of 1/2” rebar

1 8 ft. length of 3/4” PVC

Pound the rebar into the ground with an angle of 35-45° toward the center of the bed. Leave about 6” of rebar sticking out of the ground. If you plan to leave the rebar in the ground after you remove the low tunnel in the summer you might want to paint the tops a bright color or flag them so they aren’t a tripping hazard.

Slide an 8-foot length of PVC over the rebar to create a hoop, repeating down the bed every 5 feet.

How to fit floating row cover over a low tunnel frame


1 piece 83” width x 50’ long AG-30 Agribon (4’ extra for each end)

1 piece of 3/4” PVC pipe the same length as your bed

Per each five feet of tunnel:

2 3/4” rowcover clamps


Cut a piece of Agribon off of the roll about 8 feet longer then the length of the bed. That allows the fabric to drape over and close at each end of the tunnel.

To make it easy to vent the tunnel and harvest the crops, sew a simple “sleeve” down one long side of the Agribon: take 6 inches of the fabric along the long edge, fold it over, and stitch it in place.

Drape the Agribon over the hoops.

Slide your long piece of PVC down the sleeve. If you did not sew a sleeve, use more 3/4” clamps to secure the long piece of PVC to the edge of the Agribon.

Gather and secure the fabric at the each end of the tunnel with a rock, or a sand bag.

Now you can easily lift one side to vent the tunnel or to harvest delicious winter veggies.

When to plant in your low tunnel

Use the low tunnel to extend your seasons (See? We told you we’d say that.) at both ends of the year.

Plant cool-season crops in late summer and see how long you can harvest through the winter. Use the low tunnels to warm the soil in late winter or early spring and get a jump on growing the cool-season vegetables that prefer spring and fall.

Check out our article on cool-season vegetables to get ideas on what to plant—starting with the 10 seed packs in our Frost Kissed Gift Seed Tin Collection.