Growers try hooped trellises
Tubular steel may have a place in orchard trellis systems.
A new apple orchard planted to a V trellis uses greenhouse technology to support the Vs.
Courtesy of Wilson Orhard & Vineyard Supply
A few tree fruit trellis systems in Washington State are sporting a new look. Instead of flat-sided steel for the V and Y arms and supports, growers are experimenting with hoops in hopes of finding a faster and less costly way to erect trellis systems.
“What we’re doing is based on hoop house technology and materials that use tubular steel for the structure,” said Keith Oliver, orchard and vineyard manager for Olsen Brothers, a family farming company in Prosser, Washington. Oliver told Good Fruit Grower that the tubular structure was easier to install than V systems that require expertise to get the proper angles and mobile welders to put it together.
Once you decide on your row spacing, angle of the V or Y needed, and trellis height, the angle is then engineered into the posts that go into the ground and support the arms, Oliver explained. What he calls the “antlers” (arms of the V or Y) then slide into the posts and are secured with a setscrew. Curved tubular steel slides over the ends of the antlers, and a setscrew connects the Vs or Ys together for more support.
“It’s like putting a simple Tinkertoy together,” he said.
Oliver’s motivation for trying new trellis materials stemmed from the need to build a trellis for Olsen Brothers’s sweet cherry orchard that’s been planted to the new UFO (Upright Fruiting Offshoots) system. The UFO, developed by Washington State University’s Dr. Matt Whiting, is part of an effort to develop an orchard system for the future that will be adaptable to mechanical harvest, thinning, and pruning. Olsen Brothers is a grower-cooperator in the research.
“We needed to put in a Y trellis for the UFO cherries,” Oliver said, adding that their previous V trellis was made of wood. Olsen Brothers also grows hops, so long wood posts are plentiful.
“We haven’t built very many of these and don’t have the trellis experience of growers like Auvil Fruit Company who have been doing it a long time and have perfectaed it,” he said. “We were looking for something that would be easier to put up and still be strong.”
He’s watched neighboring farmers install V trellis systems and said it looks very hard to do. “I’ve seen plenty of mistakes and errors made by other growers in their V trellis construction.”
Trellis installation in rocky ground is also very difficult and can be expensive, he noted.
Oliver said that with V trellis systems, a protractor has to be used just right and everything lined up square to get the proper angles. “I’ve seen welders perched on top of forklifts out in the middle of the orchard, welding all the steel in place.”
For the Y trellis they installed in the UFO cherries, a four-foot post was pounded two feet into the ground, allowing the post to stick two feet above the ground. The antlers of the Y were attached to the post two feet off the ground, which is the same height as the horizontally trained cordon of the UFO cherry tree.
The system went in so well for the cherries that Oliver decided to try it on a new 40-acre apple block. The main difference in the apple block is that the posts are shorter—three feet instead of four. They are pounded in to leave only six inches of post above the ground. So when the antlers are attached, it becomes a V shape instead of a Y.
Some of the newer apple strains and varieties need better light interception to develop optimum color, he explained, which was his motivation for using the V trellis in apples.
$64 million question
Because the tubular hoop house material has never been tried in a tree fruit trellis before—at least to Oliver’s knowledge—the big unknown is the structure’s strength.
“Being stronger is the plan,” he said. “Hopefully, we won’t see the trellis going down.”
Oliver discussed material and structure strength at length with a steel manufacturer before deciding to try the design, but there’s always an unknown when trying something new.
“We believe it will be stronger, and there will be less of a chance for the tubular supports to buckle or crack like the flat steel commonly used,” he said. “But we won’t know for sure until we have fruit on the trees.”
Tim Welsh, horticulturist for Columbia Fruit Packers of Wenatchee, Washington, also has plans to install a tubular-style trellis this year in an apple block.