What are High Tunnels?

I’ll be talking about high tunnels more often so I thought I’d answer the question, what are high tunnels, now before I forget.

high tunnels, snow, winter growingA high tunnel is a large or at least semi-large permanent structure that covers a garden. Both of our tunnels are 1,000 square feet each. A third tunnel is being turned into a grape arbor because I don’t need the growing space anymore. High tunnels are secured in the ground or on tracks that make them movable to cover two or more growing spots, one spot at a time. The gardener plants crops in the ground rather than in small containers like those used in seedling greenhouses. Plants are grown to maturity in the tunnel.

High tunnels provide:

  • Additional warmth in cool weather, as much as a full USDA Hardiness Zone
  • Water control (rain and snow are kept out)
  • Season extension (weeks to months earlier at the beginning and end of the regular outdoors growing season)
  • Contribute to pest and disease control

A high tunnel is typically larger and sturdier than a hoop house. Disclaimer: the term “high tunnel” has been watered down to include hoop houses. Hoop houses are generally smaller and less sturdy.

High tunnels have at least one opening on an end for a door, and one or two roll-up sides. These openings help control temperature and pests. I was able to keep late blight away from my tomatoes for a month longer than the growers a half mile away because I could close the tunnel tightly on breezy and windy days.

What are high tunnels? And what do you do with them?Click To Tweet

You’ll spend more water and/or money on a high tunnel because rain and snow can’t get to the soil. If you have to pay for your water and it reflects on your sewer bill you’ll have higher bills. It’s probably still worth it to have fresh food year round. Consider rain barrels!

In some towns and cities a building permit will be required. Check your ordinances. The structure might be taxable because it’s permanent. If this is a problem you can consider temporary hoop houses or low tunnels.

high tunnels, cucumbers
high tunnels, cucumbers, tomatoes
high tunnels, boc choi