Garden Grapes and Spiders

Grape plants need a large root system and long vines with lots of leaves to provide enough water and carbohydrates to grow large grapes, Jeff Rugg writes. Flavia Karina Quiroga/Shutterstock

Q: We have had grape vines for two years now. Several of them bloomed this spring and produced dozens of clusters of grapes. After we spent the whole summer keeping the birds, raccoons, and other animals away, the grapes are finally turning color. They are sweet but they are all the size of peas, not grapes. What can we do next year to get the grapes to grow larger? Do we fertilize or water more often, or what?

A: I think the biggest problem here is that you left dozens of clusters of grapes on the vines. Young vines don’t have a large root system or long vines with lots of leaves. Both are needed for the grape plant to provide enough water and carbohydrates to grow large grapes.

Without enough roots and leaves, the plants struggle to support the growth of the grapes. As your plants get larger, they will be able to support 40 to 50 clusters of grapes. Because the plants were trying to grow lots of grapes this year, they may not have stored enough carbohydrates in the stems to produce a lot of flower buds next year. So, next year they may not have many clusters at all. To prevent an all-or-none cluster production, prune away any clusters that only have five to 10 grapes. Try to limit the clusters to 20 to 30 next year so the plant will concentrate on growing full, large grapes in bigger clusters.

You are right in thinking the vines need plenty of water. Once the vines do mature, they will produce small grapes if they are not watered enough. A drip irrigation system can help maintain the soil water level without getting the leaves wet. Wet leaves can lead to fungal diseases that spread to the grapes.

Q: We planted a flower and ornamental grass area to attract pollinators. Unfortunately, it also has attracted a whole bunch of yellow and black spiders. They are 2 to 3 inches long. Are they going to eat all of the bees and butterflies?

A: Congratulations! Your flower garden is working to benefit the wildlife in your neighborhood. You can’t control nature. As you get more “good” insects, you will get more “bad” insects and other animals. Now, I know spiders are not insects and they are not bad either. If you look closely, you will probably find praying mantises, too.

Having all of the parts of an ecosystem is a good thing. We want predators, prey, parasites, etc. to have a healthy system.

The yellow garden spider is also known by many other names, including writing spider and zigzag spider. They usually make large round webs, known as orbs, between tall plant stalks.

By fall, the two-inch-long female is often the most conspicuous spider in the garden. It is bright-yellow and black, and it sits in the middle of a large web between plants. The male is much smaller and has a separate web near the female. They both grow in size over the summer.

In the center of the web, the female creates a several-inch-long zigzag stripe of silk, called the stabilimentum. There is debate as to why they create this structure. It may be to deter predators or birds from flying into the web; it could attract insects as it glows in ultraviolet light; or it could be used to attract male spiders to the web.

To learn more about the yellow garden spider, watch the Greener View YouTube video I posted last week showing several examples of this pretty spider (if spiders can be pretty).