Growers Hope High Tunnels Open Up Sweet Possibilities

6/2/2012 10:00 AM
By Chris Torres Staff Writer

MORGANTOWN, Pa. — Corey McCleaf knows the difficulties of growing sweet cherries in Pennsylvania.

He sees it every June, when just around the time his cherries start ripening, a freak storm comes through, causing his cherries to crack.

Months of tending to his trees and money spent on chemicals for disease and insect control turn his potentially sweet returns on cherries into trees of sour grapes.

“When it rains when they’re ready to harvest, they’re done, they crack wide open,” McCleaf said.

Rather than give up though, Corey sees a potentially lucrative market for his sweet cherries, which normally are grown in arid regions of California and the Pacific Northwest.

“I know there is definitely a demand in the area and even outside of the area for local sweet cherries,” he said.

It’s a reason he spent $60,000 installing high tunnels for 600 of his cherry trees last year.

It’s something he’s been planning for the last four years, when he decided to grow a new set of trees with the eventual goal of covering them with high tunnels.

He won’t have much of a crop this year, since the trees have yet to yield a significant amount of fruit.

But his success could mean a new tool for growers looking to diversify their orchards and take advantage of a public yearning for more local fruit that’s grown with less chemicals.

Tara Baugher, tree fruit educator with Penn State Cooperative Extension, said several growers in Adams County have put high tunnels in their orchards.

“We have a number of young growers looking at growing sweet cherries this year. We haven’t been able to grow them commercially because we get rainfall before harvest and the cherries crack,” Baugher said. “This way, you don’t have cracking and there is far less disease pressure.”

Greg Lang, professor of tree fruit physiology at Michigan State University, said sweet cherries are a good option for growers wanting to try high tunnels.

He’s been studying cherry production in high tunnels for the past eight years and has found many benefits to keeping them covered.

Cherries are some of the first fruits to bloom in an orchard, so having a high tunnel can provide that extra warmth to prevent them from getting frost damage in early spring.

They can also create an environment that fruit can thrive in.

About 95 percent of the country’s fresh market sweet cherries are grown in the West, according to Lang. And with good reason. The low rainfall, low humidity and long growing season make arid regions perfect for growing most sweet cherries.

High tunnels, he said, can shield trees from rain and create a more dry environment, which he said can prevent various diseases, such as cherry leaf spot, from developing. It can also help in preventing insects like the Japanese beetle from coming in and causing damage.

Like many specialty crops though, Lang said the decision to put in high tunnels comes down to knowing if the market justifies its cost.

“I think the No. 1 issue to recognize is, adding covers has a variety of benefits, but the grower needs to have a market to appreciate those benefits,” Lang said. “Growers in the East need to know there is a market that will pay a little bit of a premium for their cherries. So it makes perfect sense for a grower who does farmers markets. It’s perfect for growers who supply regional or local high-end markets, like a Whole Foods.”

Justin Weaver has been tinkering with high tunnels in cherries on his orchard in Morgantown since 2003, and his family’s orchard was one of the first in the state to use high tunnels in tree fruits.

It started with less than an acre but has since grown to three acres.

“As I remember, it went good enough that we covered some more the following year and it kept growing,” Weaver said. “Our biggest advantage is keeping the rain off at harvest. A big thunderstorm, 2 inches of rain, will almost wipe the crop out at harvest.”

Nearly nine years after the first high tunnel was put in, Weaver still finds himself tinkering with the system.

He has found it easier to keep birds away from the trees since netting can easily be attached to it.

He’s seen a slight reduction in disease pressure, which saves him money in spray costs, and it’s helped suppress certain insects.

But even though the tunnels provide his trees some protection from frost, it’s not as good as he hoped.

He even tried reducing his spray regiment drastically, with hopes of possibly going organic, only to find it caused more problems with disease and he had to spray more aggressively.

He even thinks the drier environment is good for certain insects, such as several species of mites.

Weaver said the biggest challenge has been finding the right variety of cherries to grow under the high tunnels.

When they were first put in, they were placed over an existing planting. Some varieties did well, others didn’t.

“A lot of varieties on the West Coast have been untested, some worked out great, some didn’t. That makes it more difficult to justify the cost,” he said. “As we continue to learn what works for us here, we’ve been able to start correcting some of that. That all takes time.”

McCleaf hopes having the high tunnels will enable him to get as close to growing his fruit organically as possible.

Most of the 52 acres of fruit he grows in Biglerville, Adams County, goes to farmers markets in Washington.

He said his customers are longing for more locally grown fruit with less chemicals.

“With the tunnels, now we’re getting a little closer toward organic. There are different things to do to come close to that. Just reducing everything, that’s the main thing,” he said. “And just learning that we can spray about half as much, that was important to me. We’re selling most all of our stuff retail to customers in D.C. They are looking more toward organic.”

Weaver has even tried growing some plums and apricots under high tunnels. But he’s found the lack of dwarfing rootstocks in those varieties of fruits as a disadvantage to getting them covered.

Lang has studied nectarines, apricots and some varieties of plums, and he thinks each would benefit under a high tunnel since apricots are the first trees to bloom in spring, and nectarines and plums are both susceptible to disease.

The key to making them work, though, is training the trees to the tunnel since the plastic blocks out 25 percent of sunlight.

“We’re really talking about changing the architecture of the tree itself. We’re investigating those types of questions,” he said.


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