December 24, 2011

Wait until spring to prune grapes and then follow instructions from NMSU Extension publication.

Yard and Garden December 24, 2011

Q. How much should I prune my grapes? I have several nice grape vines, but they take up too much room and do not produce enough grapes.

Riley W.
Albuquerque

A The first thing I must say is NOT YET. It is too early to prune grapes. They are like roses and can be stimulated to grow too early by pruning, so that the plants (or the desired buds) are frozen by late winter and early spring freezes. Wait until less than one month before the expected last frost at your location. This will reduce, but not eliminate the risk of damage from a late freeze. They will probably have begun growing by that time, but do not be tempted to prune too early. In the spring when you prune, grapes should be pruned quite severely to keep them in bounds and to increase their yield. It seems counterproductive that smaller grape plants would produce more grapes, but if left unpruned, the vines will expend their energy in producing more vine rather than fruit production. Proper pruning encourages more, and higher quality, fruit production. Grapes are often pruned to a tree-like form with a trunk and a few lateral (scaffold) branches. These scaffold branches then support smaller branches that produce the grapes. The secondary, fruiting branches, should be pruned back to leave only 2 to 4 buds in the spring. That is why late pruning is recommended, with so few productive buds remaining, the chance of losing them to a late freeze is great. Information about such pruning can be found in the NMSU Extension publication H-303: Pruning Grapes to the Four-Arm Kniffin System. This publication is available at http://aces.nmsu.edu/pubs/_h/h-303.pdf, or at your local NMSU County Extension Service office. You can find other useful gardening publications at http//aces.nmsu.edu/pubs/_h/#fruit If you wish, you can use the information about pruning grapes in the publication as a guideline and modify it for your specific needs. If you are growing a grape arbor to produce shade and fruit, you can prune in such a manner as to ler the trunk grow up the arbor, then train the scaffold branches across the arbor. Prune the secondary branches as before and they will quickly cover the arbor each spring and in that form, hide the fruit from the birds by producing fruit below the leaves where you can easily reach them., nut the birds cannot easily see them from above. Such pruning may reduce the yield a little, but you will also produce shade that will be very useful in the hot days of summer.

For more gardening information, visit the NMSU Extension publications Web site at http://aces.nmsu.edu/pubs/_h , or to read past articles of Yard and Garden go to http://aces.nmsu.edu/pubs/periodicals.html

Send your gardening questions to:

Yard and Garden, Attn: Dr. Curtis Smith
NMSU Agricultural Science Center
1036 Miller Rd. SW, Los Lunas, NM 87031

Curtis W. Smith, Ph.D., is an Extension Horticulture Specialist emeritus with New Mexico State University's Cooperative Extension Service. NMSU and the U.S. Department of Agriculture cooperating.