Low tunnels are a great way to extend the garden season by a few weeks to a few months depending on your USDA zone. We’re at zone 5a and at 1434 feet elevation on the side of a hill with excellent southern exposure. This makes our location text book perfect for our garden and what’s more, low tunnels that will be able to take full advantage of the sun we get during winter. Our first low tunnels two years ago just couldn’t stand up to the snow loads we get here so we cobbed together some sturdier versions.
As our garden grew we started adding raised beds and are moving to no-till gardening. The addition of raised beds gives us the perfect opportunity to add low tunnels to extend our season. The impetus for no-till came from Lee Reich, author of the terrific book Weedless Gardening. The boost to finally rebuild our low tunnels was from Eric Rochow at GardenFork.
Do they work? Well they are well documented and examples of their efficiency are all over the internet. The well known Eliot Coleman has used them in Maine for years to extend the season at Four Season Farm and writes extensively about them. All we can say is we’ll be enjoying salad greens well into December and we have planted a few small rows of lettuce, spinach, and carrots for next spring. The carrots are already sprouting!
We have a remote thermometer in one low tunnel and the temperature is usually 15 degrees F higher than the ambient temp. On sunny days we’ve seen 90 degrees, which could cook the plants. Our next project is to add some vents to release some of that heat. Stay tuned.