If you have ever noticed that your zucchini plants start to form little squash, only to have the fruit wither and fall off, the culprit could be that some of your garden partners aren't doing their job. Squash and their relatives in the cucurbitaceae family, cucumbers and melons, require a pollinator such as bees to set fruit.
Look closely at the blossoms and you will notice that there are two kinds on these plants. Male or staminate blossoms have simple, straight stems, while female or pistillate flowers have a small, fruit-like receptacle at the base of the flower. To set fruit, pollen from male flowers must be transferred to the female flowers. If your local bees or other insects have not visited your zucchini plant, no squash will form.
You can compensate for this lack by doing the pollinating yourself. Using your finger or a brush, gather some pollen from the male flowers and put it gently onto the female flowers. It's best to do this in the morning when blossoms first open, as they are only viable for the first 24 hours. To encourage bees, avoid using insecticides of all types and consider planting bee-friendly flowering plants near or among your vegetable crops.
I plant my tomatoes together so I can set up a watering system that meets their specific needs: regular deep watering about once a week. So why do all of the plants look healthy and strong except for one, which is wilting?
By poking around into the soil at the base of the plant, I find that the watering system has not failed, but that the roots have been disturbed by gopher activity, drying the plant roots by exposing them to air. Shoving moist soil and compost into the tunnels can usually rescue plants that have been disturbed in this way, especially if they were mature plants with large root systems.
Do your cucumbers taste bitter? Researchers have found that bitterness in cucumbers is due to a chemical compound called cucurbitacin. Production of this compound is controlled mostly by genetics, and appears to vary from year to year and from location to location.
The first line of defense is to plant cucumbers that don't produce the chemical compound. I think one reason lemon cucumbers are a popular heirloom variety is that they are seldom bitter. If you do have a cucumber variety that tastes bitter, note that the cucurbitacin is likely to concentrate in the stem end of the cucumber as well as in and just under the skin. You can cut off those parts and still enjoy the fruit.
If you are growing lettuce in the summer, it too can become bitter as it ages. Lettuce is a cool-season vegetable and prefers temperatures below 80 degrees. When the weather gets warm, lettuce will start to produce a flowering stalk, and at that point the leaves will taste bitter.
Since you can't leave lettuce in the summer garden for long, plant small amounts a few weeks apart and harvest the plants regularly before they get too old. Planting lettuce where it will be shaded in the afternoons can help keep it from bolting too soon. Also, if you like crisp lettuce for your salads, pick and refrigerate your lettuce in the morning. If you wait to pick in the afternoon, the leaves will be somewhat limp.
If you planted melons, the big question is, are they ripe yet? Many types of melons, such as cantaloupe, signal their ripeness by “slipping." A slight crack completely circles the stem where it is attached to the fruit. If the fruit comes off easily, leaving a smooth cavity, the fruit is ready to eat.
Some types of melons, such as Crenshaw, casaba, and honeydew, do not slip. Watch fruit for a change in color, usually to yellow, and feel the blossom end to see if it is softening. Some melons give off a wonderful aroma when ripe.
Watermelons are a different genus from other melons, and assessing ripeness is different. Rapping the side of the fruit with your knuckles is a tried and true technique. A light or metallic sound indicates that the fruit is still green. A dull, hollow sound indicates ripeness. Watermelons also will have a white or yellow spot where the fruit rested on the ground, and tendrils close to the fruit will darken and dry up.
Napa County Master Gardeners are ready to answer these and all your garden questions, all summer long. Enjoy your summer produce.
Workshop: Napa County Master Gardeners will conduct a workshop on “Cool Season Veggies” on Sunday, August 17, from 2 p.m. to 4 p.m. at the Yountville Community Center, 6516 Washington Street, Yountville. Grow your own vegetables even when days are short and nights are cold. Learn which vegetables thrive in cooler temperatures, how to protect them from heat when they are getting started, and how to time planting to ensure months of harvest. To register, call the Parks & Recreation Department at 707-944-8712 or visit their web site. Workshop fee is $10 for Yountville residents, $12 for others.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.
Napa County Master Gardeners welcome the public to visit their demonstration garden at Connolly Ranch on Thursdays, from 10:00 a.m. until noon, except the last Thursday of the month. Connolly Ranch is at 3141 Browns Valley Road at Thompson Avenue in Napa. Enter on Thompson Avenue.
