You’ll need “a nice, open piece of ground” that is well drained and unimpeded by a tree line that can interfere with ventilation, Evans says. Don’t put your tunnel at the bottom of a hill where cold air collects.
Roberts Family Farms in Layton, Utah, started growing tomatoes in tunnels three years ago and added strawberries this year, says partner Tyson Roberts.
There are differences from growing in a field, he says. For example, fertilization requirements for the tomatoes are different, mildew and fungus can be a problem if you don’t allow for ample ventilation, and lack of air movement can hinder pollination.
“We learned that the hard way,” Roberts says. This year, he left the doors of his tunnel open for a few hours every day to enhance pollination.
Roberts built two fairly permanent steel structures, each 30 by 65 feet, for $1,300 apiece. You can buy kits for $2,000 to $10,000, but a neighboring farmer sold him the parts from tunnels he had taken down.
One advantage of the hoop house is that it allows you to gain customers in early spring and keep them through the fall, Roberts says. He can charge up to $3 per pound for tomatoes at farmers markets early in the season.
Grower Bradford raises high-value red and yellow bell peppers in his tunnel.
He has 20 years experience with greenhouses, but he added a 30- by 50-foot high tunnel to his operation last year.
Bradford paid $3,000 for the frame and plastic covering, and took in an extra $3,000 to $4,000—minus about $800 for labor and expenses—by extending his growing season.
He plans to build another this fall, if he can find the time. Eventually, he may convert the tunnel to a greenhouse.
A help for small farmers
Tunnels are especially beneficial for small-scale growers who do direct marketing and are looking to expand their growing season and the range of products they can grow, says Brent Black, Extension fruit specialist for Utah State University in Logan.
Black has had good luck with strawberries, some success with raspberries, and he is experimenting with blackberries, which are “marginally hardy in our climate.” Colleagues are looking at items, such as lettuce, spinach, chard and bok choy.
They grow in steel-framed structures about 90 feet long and 24 to 30 feet wide that cost from $2,000 to $4,000, depending on factors, such as how sturdy they are and how much ventilation they offer.