Zucchinis: Not That Easy to Grow Anymore

As gardeners I am sure that somewhere along the way we have heard the zucchini jokes. You know, like the one about how neighbors all hide when you try to give away your produce. It seems it used to be that you could not stop a zucchini plant from producing.

Now, calls to the Johnson County Extension Gardening Hotline (913) 715-7050 or garden.help@jocogov.org paint a different picture, as people wonder what it takes to grow this crop. There are several potential problems that could be the cause for lack of production.

Zucchini Flowers But No Fruit

“I get lots of flowers but no fruit,” is one common comment. Zucchini have separate male and female flowers. The males produce the pollen for female flowers that have the tiny squash developing behind the bright orange flowers. Squash produce numerous male flowers for each female. Early on, they develop male flowers before the females. This over-development of the male flowers is to ensure that pollen will be available to fertilize the female flower or fruits. The solution: wait it out, as a healthy plant should start to produce female flowers.

Zucchini Fruit Set But Rot

Rainy weather that continues throughout the month of June can lead to fruit rot on squash. These damp conditions can cause the ends of the fruit lying on the ground to decay. The solution: mulch the plants to keep the fruit off the ground and dry.

Squash Bugs

Squash bugs have long been a nemesis of all members of the squash family. These grayish-black and orange bugs attack the plants by the hundreds, sucking the sap and nourishment from the plant resulting in the collapse of the vine. Squash bugs are easiest to control when they are small grayish nymphs starting to feed. The solution: monitor the plant for the presence of the insect and spray with an insecticide as soon as they appear. Be sure to spray around the base of the plant and up under the leaves for best control.

Squash Vine Borer

Of all the problems with zucchini this may be the worst and most difficult to control. The vine borer is an insect that lays its eggs on the main stem of the plant where it emerges from the ground. The eggs hatch and bore into the stem. As the insect develops into large, dirty white grub-like larvae, it destroys the vascular system of the plant resulting in its death. Once the plant has collapsed there are no controls. The solution is to start preventive insecticide sprays soon after the plant has emerged from the soil. This will require repeated applications every couple of weeks for best control targeted at the plant’s main stem. The good news is that applications for the borer will also control squash bugs.

Based on all these problems one might ask, why grow zucchini, especially when you can buy them at the supermarket for around a buck a pound? We already know the answer to that question, as fresh homegrown always taste better. Times have changed and now people tend to hoard their bounty. Because, as we know, what would summer be like without fresh zucchini slices, grilled zucchini, zucchini bread, or my favorite, chocolate chip zucchini cake?

For more information K-State Extension has developed a great fact sheet on the pest problems of squash, Squash Bugs and Squash Vine Borers http://www.ksre.ksu.edu/bookstore/pubs/MF2508.pdf

By Dennis L. Patton, M.S., County Horticulture Agent, K-State Research and Extension/Johnson County

Have questions?

The Garden Hotline is staffed by trained EMG volunteers and Extension staff who will assist you with questions.

Phone: (913) 715-7050

Email: garden.help@jocogov.org