Last week some of the final steps for Eden Hall’s Solar High Tunnel took place. The tunnel, at 3,000 square feet, will provide students and the local community with fresh produce year round. The tunnel is solar powered, with full solar panels that heat water for radiant floor heating throughout the bitter temperatures of winter. The side walls have panels that can roll up automatically and are controlled by a thermostat. In the winter the system will be set to maintain a temperature of at least 42 degrees, even on the coldest days.
Solar high tunnels provide protection to the crops by creating a shelter from the wind, rain and snow. The polyethylene sides roll up on ideal temperature days to let the outside air flow in. On overly hot days, exhaust fans come on, relieving the crops from heat.
The solar high tunnel provides an extended growing season and a protected environment for the crops. This is Chatham’s first heated high tunnel and it will provide harvest year round for its students, faculty and local community.
A fellow intern, Casey and I had the opportunity last week to help with one of the high tunnel’s final steps—pulling the polyethylene over the 100 foot long building, and keeping it in place with wiggle wire. Together, nine of us worked in unison. The process was quite comical yet efficient, starting with hammer throwing. Tony, a recent graduate from the Falk School of Sustainability at Chatham, knotted some rope around a hammer. Then with the grace and form of a softball player, he lobbed the hammer over the structure and successfully got the rope to the other side. He did this seven times.
After the hammer throwing, we placed the polyethylene (plastic—which was quite heavy) parallel to the structure and used tennis balls to wrap and knot the other end of the rope. We pulled the edge of the polyethylene over the tennis balls, then wrapped the rope underneath the balls and knotted them into place. We did this seven times. Once all seven tennis balls were knotted and ready, the crew walked to the other side of the tunnel where the loose rope was waiting for us. We each took a rope and waited for instructions from Ray of Four Seasons Tools (the company that installed the high tunnel) who was perched on a ladder overlooking the tunnel’s entirety. The instructions were simple, when he said go, we were to pull, and when he said stop, we were to stop pulling.
Once everyone was in place and go was shouted, seven of us started pulling on our ropes. After a couple of seconds we could see our progress, the plastic was starting to ascend over the hoops. Then we heard stop and all seven of us halted to this command. The plastic was stuck. Luckily we had Rowan from Four Seasons, outfitted with a long pole with an empty gatorade bottle on its end. Rowan found where the plastic was stuck and jolted his gatorade power stick up into the plastic, where it bounced over its obstacle and seconds later we were told to go again. There were quite a few stops yelled over the next couple of minutes, but then the plastic started to descend into our vicinity and we all looked at each other and smiled. We had done it. The plastic made it to our side and covered the high tunnel in its entirety. It felt like success.
The sun was heavy on our shoulders and the air threatened rain. The next step was to stabilize the plastic with wiggle wire. I had never used wiggle wire. It is exactly what it sounds like—a wire that curves up and down. Underneath the polyethylene was the high tunnel, with an internal tracking system that we would wiggle the wire into. Working in pairs, that is exactly what we did. One of us pulled the plastic taut while the partner pulled the wire up and down into the track, ultimately stabilizing the plastic in place. We did this around the perimeter of the whole tunnel and up and down the ends. The whole wiggling process took under an hour, with the threat of a rainstorm and the promise of cold beer speeding us along.
In the end the rain never came. But it will, along with wind and snow and ice. The solar high tunnel will protect against these forces throughout all seasons. It will protect our mighty vegetables that will feed us when we are hibernating in our homes. Even of the coldest of seasons, we will be getting fresh, organic produce. That’s the beauty of this solar high tunnel—it provides, it protects and it is a mighty fine perennial.