Some Grapes Require Thinning of the Foliage During Spring Months

Q. After the grapes set their fruit in the next couple of weeks can the vine be trimmed or does it need to grow to provide shade and nutrition to the grapes?
A. As long as your vine is growing vigorously you can continue to prune through the summer. You want to make sure the berries are shaded by the leaves to prevent sunburn.

These are table grapes. We will go through the vines during the early part of the growing season and pull new growth that we will not need for next year out of the vines. We have to be careful not to pull too much out and expose the bunches. But by pulling growth out of the vines we open up the canopy for better light penetration, better penetration by pesticides that might be applied and reduce shading on itself. Table grapes are much more vigorous than wine grapes.

            We trim the vines back several times during the growing season. Usually table grapes are more vigorous than wine grapes. When the vine is shading itself or out of control it needs some pruning or thinning of its growth.

This is something new grape growers to the desert discover too late. They think you can grow grapes with trellis systems from more mild climates. Wrong, wrong, wrong. This is a very harsh climate and the sun can be very damaging. Grape bunches must be protected from intense direct sunlight.

We will try different types of trellising at the Orchard. A favorite of ours for table grapes is the use of "catch wires" above the double wires used for the the cordons. As new growth emerges from the cordons they are "tucked" on top of the double catch wire above where they provide shade for the grape bunches and reduces sunburn. The new growth is "thinned" so it does not shade itself, is more manageable and thinned for better penetration by light and pesticides (Bt, Spinosad)

Use grape training systems that provide crop cover as they are maturing.