2007 Year in Review

Pruning Grapes

If you are wondering when to prune your grape vines, late February through mid-March is the time, said a University of Illinois Extension horticulture educator.

"If the grapes are being grown on wires, choose a vine along a wire that looks moderately vigorous," said James Schuster. "Count about 12 buds out from the trunk or main stems. About one-quarter inch beyond the 12th bud, cut the vine off. Repeat this along the wire in both directions." Once the lateral arms with 12 buds have been chosen and pruned, remove all other vines coming off the main trunk. Remove these lateral vines at the main stem.

"When pruning grapes, it is recommended that anvil-type pruners be used. For some reason, grapes respond better to pruning when the cut tip is slightly damaged. Anvil pruners do this without causing excessive damage. An anvil pruner should be used only on grapes and no other woody plant material.

"No tree paint or tars are needed to coat the cut ends. Treating the pruning wounds has been proven to be mostly cosmetic. There are no benefits for using paints or tars to justify purchasing or using them."

If your grapes are producing little if any fruit, there could be several reasons, Schuster said.

"The grapes may be getting too much fertilizer either directly or indirectly (lawn fertilizer). Strong, long, and vigorous vines often indicate too much fertilizer," he noted. "Reduce fertilization and keep lawn fertilizers away from plants by at least 20 feet.

"Another possibility is that the grapes are not getting enough fertilizer. Thin, short, weak growing vines are an indication of this. Fertilize the plants. It may take a year or more of reducing fertilization or increasing fertilization of the grapes before yields improve."

Grape plants should be planted in full-sun locations and away from tree roots. However, the grape bunch does not need to be in sun to ripen; therefore do not prune vines or leaves off in the summer.

"If grapes are not ripening evenly, there may be a herbicide problem," he said.

by  Editor, theCity1.com
February 22, 2007