NC Cooperative Extension

Grape Problems

Grape Problems

Someone asked the question “why did my grapes fail to produce last year?”  There could be a number of reasons.

Shade – Grapes planted in a shady area or if a new tree, building or fences shaded the vines then this could affect production.  Grapes and most other fruits need at least 8 hours of full sun each day.

Pruning and Training
– Both bunch and muscadines produce on new wood.  If they are not properly pruned every year then you get more and more old wood that is not productive.  Training also can affect fruiting. Proper training ensures that the entire vine gets adequate sunlight for optimum production.

Disease – Bunch grapes are susceptible to a number of diseases that can limit production.  The last few summers have been very wet and this favors fungal diseases.  If you have experienced disease problems or if we have another wet summer you may want to consider a spray program for bunch grapes.  If you are interested in a bunch grape spray program call the Extension Office at 652-8104.  Muscadines are more disease resistant and don’t need to be sprayed.

Poor Fertility
– Low pH or poor soil fertility can also affect grape production.  A general fertilizer recommendation, for mature vines, is 2 pounds of 10-10-10 per plant applied in March and again after fruit set.  A soil test is recommended to determine exact fertility need.  The soil test will also determine the proper pH of the soil and lime requirements to correct the pH.

Cold Damage – A late spring frost can kill the grape buds and reduce the amount of fruit produced.  Generally grapes and other fruits planted in a low area or on a south face are more likely to experience this problem.  Low areas collect frost and south slopes warm earlier in the spring making grapes more susceptible to a late spring frost.  The best locations for vineyards are on the side of a gentle slope and facing either north or east.

For additional information on growing both muscadine and bunch grapes contact the Cooperative Extension Service and ask for “Grapes and Berries for the Garden.”

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