57°F
weather icon Cloudy

Some factors cannot be controlled when growing grapes

Question: We had a problem with our Thompson seedless grapes. The grapes are about the size of a BB and dried up and fell off.

Unfortunately, there is not much you can do about that. It was poor pollination. Climatic factors have a significant effect on fruit set. Fruit set is greatly reduced when temperatures fall below 65 degrees Fahrenheit or exceed 100 degrees Fahrenheit during set. Rainfall or high humidity may reduce fruit set, hindering pollination. Rain can also interfere with the germination of pollen grains and inhibit fruit set. The berries appear to set and then fall off when they reach a small size.

Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at extremehort@aol.com. Visit his blog at xtremehorticulture.blogspot.com.

MOST READ
Don't miss the big stories. Like us on Facebook.
THE LATEST
The sun sets on my days as RJ’s gardening columnist

Thanks to everyone who has supported my journey into journalism by reading my gardening column over the years and contributing questions.

What’s ailing my mature pine trees?

When native pine trees are grown on their own they will develop taproots or sinker roots for stability and to secure enough water.

Gaining control over this annual weed is not easy to do

To make sure it doesn’t return you have to interrupt the seed-to-flowering-plant cycle at least for a couple of years and fill the voids with something competitive.

Why did my bird of paradise plants quit blooming?

They were in bloom when we planted them five or six years ago, and they bloomed the following year as well. But they have not bloomed again.

MORE STORIES