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Growers Learn about High Tunnels, Organics, Pruning, Staking and More

The Tomato Magazine
February 2007

One of the largest groups of tomato growers in the history of the event was in attendance at the 2006 Great Lakes Fruit, Vegetable& Farm Market Expo tomato session, held Dec. 5 at the DeVos Place Convention Center in Grand Rapids, Mich.

Ron Goldy, district agriculture (vegetables) educator, Michigan State University (MSU) Extension, moderated the packed session which drew guests from all
over the United States, particularly the East Coast, as well as Canada.

Session speakers included: Ed Weaver of Weaver’s Orchard, a fourth generation family farm in Berks County, Penn.; Dale Mutch, an extension specialist with the W.K. Kellogg Biological Station, MSU; Fred Leitz Jr., with Leitz Farms LLC, Sodus, Mich., an organic farm; and Stephen Olson, a tomato researcher
with the University of Florida, North Florida REC, Quincy, Fla.

High Tunnel Tomato Production
Ed Weaver touched on his recent experiences with high tunnel tomato production. The farm’s primary crop is apples but, like many in agriculture today, the grower has been branching out into other fruit and vegetable crops, including tomatoes. The farm’s on-site market has become a primary sales outlet. The farm
also offers a “pick your own” option for crops such as blueberries, strawberries and brambles and also markets peaches, apricots, plums, nectarines,
cherries, apples and pears.

“After numerous crop losses to our sweet cherries—due to birds and other problems—we were searching for a way to protect the crop, and in the spring of 2003 discovered the Haygrove high tunnel,” Weaver told the group. The first tunnels were constructed over existing cherry trees. The following year (2004), as the family became aware of the potential for growing other crops under high tunnels, one-fourth acre of tomatoes was planted.

“In 2005 and 2006, we planted 700 tomato plants in a new three-bay Haygrove structure that was 120-feet long,” the speaker explained. “Each bay is 28 feet wide with fi ve rows planted per bay. Plants are two feet apart. We also planted small numbers of plum tomatoes, grape tomatoes, hot peppers and eggplants.”

Raised beds were formed and drip tape buried prior to laying a black fabric weed barrier, he detailed. The rows were 4.5 feet apart, and plants were placed two feet apart.

One row was left open in the middle bay to allow space for a small sprayer to do its job.

The first of the tomato plants were planted on April 18, Weaver said. These included 200 Mountain Spring and 100 BHN 589 plants in 4-inch pots. On May 2, 150 Mountain Fresh, 50 Sebring, 50 Carolina Gold and 50 Health Kick plants were planted.

The plants were staked with 4-foot wood stakes, he said, and were tied with tomato twine throughout the season. Trickle lines were used for irrigation and fertigation. Leaf analysis was done two times during the season; the reports were used to adjust nutrient applications.

“For pollination, we walked through occasionally with a leaf blower,” the speaker said. “Other times, we went through shaking the stakes. We also placed bumblebee hives in the tunnels when we were finished using them in other crops.”

Combinations of Bravo, Kocide, Manex, Tanox and Curzate were used for disease control, Weaver said. Insects were controlled with Lannate, Provado, Danitol and Acramite.

“Our most difficult pests were thrips and mites,” he noted. “Our structure is located at the edge of our property where a neighboring Christmas tree farm is host to many insects, and it seemed that every time the thrips were wiped out, they were back in a few days.”

As for the 2004 crop, Weaver said he harvested 556 twenty-five-pound boxes of tomatoes, or about 18.5 pounds per plant (approximately 2,800 boxes per acre). Quality was split: half No. 1 grade and half No. 2. Income levels have improved as the family gained experience and the markets improved. The 2005 crop averaged about $12 per 25-pound box; the 2006 crop averaged $15.

One production challenge, the grower said, has been dealing with excessive plant growth. Plans are to reduce the number of rows inside each tunnel by one to allow more room for air circulation and for moving equipment through to do the spraying, Weaver said.

Organic Production Presentation
Dale Mutch shared organic tomato research conducted at the MSU Southwest Michigan Research and Extension Center. He and colleagues Ron Goldy, Virginia Wendzel and Todd Martin have been looking at various cover crops aimed at boosting organic tomato production.

The highest above ground biomass in the fall of 2005 was collected from oilseed radish (OSR) without compost. There was no difference between OSR with compost and oriental mustard (OM) with or without compost. Rye produced more aboveground biomass as compared to hairy vetch with or without compost. All cover crop treatments, except hairy vetch, reduced weed biomass, Mutch reported. Fall applied compost did not infl uence cover crop or weed

In the spring of 2006, OM provided the lowest weed biomass for all treatments. Rye biomass increased in the spring while providing good weed control. Hairy vetch increased biomass in the spring but never out-competed the weed biomass. All cover crop treatments significantly reduced weed biomass as
compared to the control (no cover crop), the speaker said.

“Dr. Goldy recommends that organic tomatoes be picked at less than vine ripe so they have less time to be exposed to disease organisms and other potential damage (cracking, insects, etc.),” Mutch added.

“They should be harvested just as they begin to change from green to red. Internal ethylene will cause them to continue to ripen off the plant, but with less exposure to potential damage.”

Following Mutch, Fred Leitz Jr. reviewed some of the challenges he walked through in order to be certifi ed as an organic tomato grower. There defi nitely was a learning curve, he acknowledged, noting that he now feels greater confi dence than he did at the beginning.

One of the advantages of going organic was reduced chemical costs, he said. However, most, if any savings, were probably offset by additional hoeing and hand weeding costs, he admitted.

“Would I do it again (certify to grow organically)? Yes,” the grower said. “Would I increase acreage? Probably,” he smiled.

Value of Proper Pruning and Staking
The UF’s Stephen Olson addressed two topics, “Tomato Pruning and Staking” and “Physiological, Nutritional and Other Disorders of Tomato Fruit.”

While the cost of pruning ranges from $0 to $40 per acre and comprises a “very small part” of total production costs, it can have a “very large impact on yield and quality,” Olson stressed.

“The degree of pruning is variety dependent,” the speaker said. “With weak determinate varieties such as ‘Solar Set,’‘ Equinox,’’Solar Fire’ and plum types,
only minimal pruning is necessary. With these varieties only the ground suckers (those located at the cotyledons) need to be removed or none at all. Heavier pruning, especially to the fork, with these varieties will result in signifi cant yield losses and can lead to increased sunburned fruit, blossom end rot and cat facing.

“With more vigorous determinate varieties such as ‘Agriset 761,’ ‘FL 91’ and ‘FL 47,’ heavier pruning such as removal of ground suckers plus two additional suckers may result in increased yields and fruit size,”Olson explained.

Staking increases yield and improves fruit quality by keeping plants and fruit off the ground, the speaker said. It also improves spray coverage and allows better air circulation so plants dry off quicker. Staked tomatoes are also much easier to harvest and less damage is done to the vines.

The full text of Olson’s two presentations will be reported in upcoming issues of this magazine.

© 2007 Columbia Publishing

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