High tunnels

By Rennie Phillips

Since we moved to Scott City back in '86, we have grown a garden pretty much every year. I can't remember not having a garden even when we lived on Harvard. Several things seemed like they always made gardening a little more difficult here in Missouri. In the Spring it always seems like it rains about the time I want to plant or get my garden ready to plant and then plant. It also seems like now and then it gets pretty cold towards the end of April. This year it frosted late in April which set back most gardens. Another problem is the fungus which is a result of the super wet climate we live in. The high tunnel is one solution for all of these problems. By growing under cover we protect our crops from the rain, from the cold and to a degree from the fungus.

A high tunnel is very similar to a greenhouse. The only difference between the two is that in a high tunnel one can open up the ends and the sides while in a greenhouse one can't. Virtually what one ends up with is a garden with a plastic covering over it. There are all kinds of variables associated with high tunnels but this is good general description.

We put up our first high tunnels about six or seven years ago. The first two high tunnels were both 24 by 48 feet in size. Maximum height is about 12 feet or so. We decided to put up two initially since we were working with the NRCS, or Natural Resources Conservation Service. So glad we did. There are virtually hundreds of different kinds of high tunnels. I had been ordering garden supplies from a garden supply out by Jeff City and since they had high tunnels we went with them. The high tunnels we bought were built by Zimmerman.

I didn't have a trailer big enough to haul them back from southwest of Jeff City so we hired a friend to haul them back for us. When he dropped off the two 24 by 48 kits I was surprised at all the pieces. Lots of pieces. Lots and lots! So the process of building the high tunnels began.

Our first task was digging the holes for all the ground posts and then cementing them in. There were 16 metal posts along both sides so we ended up using 32 of the 80-pound sacks of concrete mix. Once the concrete set up and cured we began putting up the bows or rafters. I wanted a super strong rafter so we had them designed as rafters with a "w" support on each one. Cost a little more and took more time to build but well worth the time and money.

One could buy end kits for each end of the high tunnels but we chose to build our own out of treated wood. Since I am prone to overbuild for strength ours are super strong. The posts on each end are 4x4 treated wood and cemented in. We dug two foot deep holes for the 4x4's and then used over two bags of concrete mix in each hole.

We placed doors at each end that are 10 feet wide by right at seven feet tall. This really opens up the ends so that the tunnel can cool down during the days and nights. The sides can be rolled up right at four feet so each side allows air to flow through the tunnels and cool them down. But even with the sides open and having the doors open the high tunnels still really get hot in the summer heat. When we bought our first two high tunnels we also bought a 30 percent shade cloth for one tunnel. This shade cloth blocks 30 percent of the sun's rays so it doesn't get as hot. It's kind of like when a cloud shades the sun on a hot summer day. We decided to only buy one shade cloth for one tunnel and let nature take care of itself in the other high tunnel. The only problem we had with the tunnel without the shade cloth was some of the tomatoes sunburned. A bushy tomato plant with plenty of leaves would be fine without a shade cloth.

We have grown cucumbers, tomatoes, beets, green beans and zucchini in our high tunnels. Our go to crops to grow in the high tunnels are tomatoes and cucumbers. We can grow about 125 tomatoes and 45 to 50 cucumber plants in each of our 24 by 48 high tunnels. We've found that the temp outside compared to the temp in the tunnel is about a 5 degree difference. So if the outside temp gets down to 26 or 27 degrees it will freeze in the tunnel.

We enjoy the high tunnels enough to build one more, a 30 by 60. We are about ready to put the plastic on.