High Tunnel Construction

We live in central North Carolina, nestled midway between the mountains and the beach and, also, right on the line of growing zones 7a and 8b. I'm a northern girl, so I love our long growing season and mild winters, but... there are some fantastic flowers we could be growing if only we had a little longer season and little bit of protection. The idea of a longer growing season makes me start dreaming of ranunculus, anemones and tulips blooming early in the spring and then stock, heirloom mums and dahlias continuing to bloom well into November...

So, we bought a high tunnel. Well, we bought a kit - now on to construction... 

I'm not going to claim construction expertise here, but I would love to share some tips and tricks that we learned along the way. We ordered our kit from FarmTek. It is the GrowSpan Round Premium High Tunnel 96 ft long with roll-up doors. 

A quick note about delivery...we've off-loaded plenty of shipping containers and pallets using the forks on our tractor. But, not this one. The Tunnel kit is really heavy (more than out 1300# lifting capacity) and requires long forks arms. If you can, have it delivered to the local shipping dock, and they'll help you load it into your truck and/or trailer. 

Now, on to construction - read the directions, do a much of math and measure. Then, measure again and make sure your angles and spacing are proper. Right angles and level ground are a must!

The first tip I'll share is to rent an air fence post driver and a giant diesel air compressor to run it - you can get both from Sunbelt Rentals, and we only needed the rental for a few hours. Trust us; there are too many posts to put in the ground by hand.

After setting the posts and installing the ceiling purlins and supporting the sides, you'll need to build the tunnel ends. The weird thing about the ends is that you attached the plastic for the door, THEN, the rails for the roll-up door. It feels counter intuitive, but it works. You only affix the top portion of the door to the wood end frame, then it hangs free to roll up between the metal support and wood frame (see pic).

Our biggest challenge was pulling over the plastic cover. Search youtube, and you'll see a couple of different ways to accomplish this task. The method we wanted to use (but didn't) was to pull from one end of the tunnel with the plastic more or less folded up. The result would have been the folded plastic laying nicely across the top of the hoop, then once pulled the full length, you'd unfold the sides and use gravity to cover the tunnel. Well, for us, we lacked the proper equipment - you need to be able to reach the top of the tunnel at either end and at least in one place inside. Too many too tall ladders or lifts required...

So, here is what we did - we unfolded the plastic so it laid the long way along one of the tunnel sides. Gather some friends (you'll need at least three, this stuff is heavy!) on a NON-WINDY DAY, bunch up sections of plastic and tie ropes to it. Throw said ropes over the tunnel and pull from the other side.

I think this tunnel will be a game-changer for our business, and I'm excited to see the results in flowers. This season we'll be growing ranunculus, anemone, tulips, sweet peas, snapdragons, pansies, and lisianthus under the tunnel. Stay tuned to see how they grow!