Growing Magazine - August, 2012
Orchard Management: Establishing an Organic Orchard
Growers can gain additional in-come by meeting the demand for organically grown fruit, but organic tree fruit production isn't easy.
Dr. Jim Travis, retired director of Penn State's Fruit Research and Extension Center in Biglerville, Pa., worked with researchers and numerous growers, and now he's sharing with other growers what he has learned about his first few years of organic production.
Orchard spacing of 5 feet between trees and 16 feet between rows allows ample sunlight as well as space for mowing and spraying equipment. Tree wraps deter deer and other wildlife, and help protect against damage from mowing and cultivation equipment that must work as close to the tree as possible.
PHOTOS BY SALLY COLBY.
Young Crimson Topaz, a scab-resistant variety planted in a north/south orientation this past May, will be trained on a trellis to create a fruiting wall.
"I'm a firm believer that organic production is based in science," said Travis. "My approach is based on the biology of the organisms combined with airflow and sunlight."
Travis knew that certain geographic factors would be the first line of defense in successful organic production: good airflow, soil drainage, slope and exposure to sunlight. "The orchard rows are north/south so that both sides of the tree have sunlight," said Travis. "The more sunlight hits the leaves and fruit, the less disease there is."
During the initial planning stages, Travis realized that he'd need something to deter deer. He considered dogs, electric fence and tall deer fencing. He settled on deer fence at a cost of about $1,000 per acre. Travis looked for locust fence posts because they don't require chemical treatment, but couldn't find any when he was ready to install the deer fence. He settled for green oak posts soaked in organic copper solution for 24 hours. "The fence provides a way around the orchard so deer can travel established trails without having to jump in and out of orchards," said Travis, "and there's plenty of deer habitat preserved."
Young trees are trained to the wire as soon as they reach adequate height. This system is a substitute for the trunk and scaffold branches that provided support in older production systems.
Since there was no history of growing crops on the land, Travis started organic production immediately. Prior to planting, he tested the soil and used 2.5 tons per acre of quarried lime to raise soil pH to 6.5. Once the soil was amended, Travis reviewed and selected two scab-resistant apple varieties. "You can control scab with lime sulfur, but it's difficult," he said. "Successive applications of sulfur year after year can affect soil pH."
Travis selected Crimson Topaz, a popular European apple that is scab-resistant and reportedly has some resistance to powdery mildew, and Gold Rush, a late-maturing yellow variety that's a consumer favorite. Travis says that although Gold Rush is resistant to powdery mildew, it's somewhat susceptible to cedar apple rust.
Travis established two orchards using two different planting methods. For one orchard, a neighboring grower prepared the ground using a chisel plow, then planted 1,400 trees with a tree planter in one morning. In another orchard, Travis and his wife dug holes using an auger and hand-planted to put 1,000 trees in the ground. Although the hand-planting took about a month and was labor-intensive, Travis says that it was actually less work because the chisel plow that preceded the tree planter brought many large rocks to the surface that had to be removed.
Locust posts support a 13-foot trellis system in Travis's organic orchard.
"We wanted to make sure to get trees at proper planting depth," said Travis, as he explained the planting procedure. "If the trees are too far out of the ground, we'd have too much dwarfing, and if the trees are too deep, we might get scion rooting or too much growth." Each tree has poly wrap at the base to prevent damage from equipment, especially mowing. "I try to mow as close to the trees as I possibly can," said Travis. "I also use a cultivator, which can damage trunks. The wrap also helps protect against rabbit damage and winter injury." Locust posts will support trellises, which will be spaced fairly close together to support the weight of high-density production.
Travis says that the expected pack-out for organic tree fruit is 30 percent, but his goal is to market 80 percent of the crop as fresh fruit. To achieve that pack-out rate, Travis knew he needed uniformity in tree size, vigor and spacing. The orchard spacing is 5 feet between trees and 16 feet between rows. Travis admits that he sacrificed valuable space to separate rows but decided that he needed ample room to get a tractor and mower in for weed control. Trellises will be 13 feet high to gain air circulation down the rows and across the trees, and will allow sunlight penetration to suppress disease.
Pheromone traps help Travis monitor insect presence in the orchard.
"For most diseases, you need at least six hours of wetting, so that could be three hours of wetting and three more hours to dry off," said Travis. "If there's as much sunlight as possible, the leaves dry faster. If you don't have enough sunlight, there's more disease risk."
Travis has taken numerous soil tests, and withholds fertilizer until the trees need it. "Diseases love vigor," he said. "Most diseases infect the succulent growing tips, so the more succulent tissue there is, and the longer it's there, the more disease there is." In one block that required fertilizer, Travis used poultry manure (75 pounds of N per ton) at a rate of half shovelful of manure at the base of each tree, which translates to 35 pounds of N per acre.
Dr. Rob Crassweller, professor of tree fruit science at Penn State University, explains that proper pruning will be a key factor in keeping trees productive. "A normal apple tree sends out shoots one year, then the next year that shoot will form spurs," he said. "Fruit is produced on two-year old wood and older. A peach tree will send out a shoot this year, and next year there will be fruit on that shoot. An apple tree will grow out this year, then you have to wait another year, because it has to form spurs. Certain varieties of apples are spur types, which grow a long shoot and form a lot more spurs (which means more fruiting units) than a non-spur type. Spur types work better as freestanding trees."
Crassweller noted that the goal is to integrate the growing system with the environment. "Trellises are expensive," he said, "but on an apple tree, the best fruit with the most color and least disease is on the outside. We're trying to make the whole orchard the outside. That means less disease pressure, and (it) will allow me to use sulfur or lime sulfur to control disease and to get that 80 percent pack-out. We want to set it up so that the tree has the advantage, not the disease."
Frequent scouting and a good hand lens allow Travis to detect and control pests before they become unmanageable.
Travis admits that despite basing his organic orchard in science, he has had challenges, the worst of which is weeds. "I spend time on weeds when I should be thinning apples or training trees," said Travis, "but I have some ideas on what to do."
The author is a frequent contributor and freelance writer who farms and raises Great Pyrenees in south-central Pennsylvania.