Why no tomatoes?

The production of luscious, juicy, ripe tomatoes seems to be every vegetable gardener's passion. Why aren't tomato plants producing fruit? There are abundant flowers and vigorous, thick foliage, but no tomatoes.

Poor fruit set can occur for a number of reasons. Have you noticed the weather? Temperatures have been very hot. We don't like it, and neither do our vegetables.

Extreme temperatures, above 90 degrees or below 55 degrees, for extended periods will make blossoms drop off without setting fruit. Dry soil will also cause blossoms to dry up and fall off. Plants that are in the shade and receive less than six hours of sunlight per day will not set fruit. Finally, applying a fertilizer with too much nitrogen will encourage the growth of many leaves, but no fruit.

There isn't too much you can do about the heat, except for shading plants during the hottest part of the day, which is labor-intensive. However, you can control the watering. Don't allow the soil to dry out. Mulch the tomato bed with organic matter: straw, mulch, compost, grass clippings (nothing contaminated with weed killer) or leaves.

To ensure that they receive enough sunlight, only plant tomatoes in sunny areas. Fertilize them with a vegetable food low in nitrogen. Nitrogen content is denoted by the first number of the fertilizer ratio, such as 8-10-8 or 10-10-10, on a fertilizer bag. Nurseries sell many fertilizers formulated for tomatoes. Plants don't care if a fertilizer is organic or inorganic.

What about other veggies that aren't setting fruit, such as cucumbers, melons or zucchini? All of these are members of the cucurbit family. Usually, poor fruit set results because of poor pollination. These family members have male and female flowers that don't always synchronize their bloom times. Even when the male and female flowers bloom at the same time, sometimes there are no bees due to declining populations. Using insecticides inappropriately can reduce numbers of bees, and parasites and diseases can also impact hives.

You can try to hand pollinate with a paintbrush. The male flowers are on the ends of long stalks. The female flowers are not on a stalk, but are attached to a swelling that looks like a tiny fruit. Touch the male flower with the paintbrush, and then touch the inside of the female flower with the paintbrush. I might have to try this because my cucumbers are not bearing yet.

For more information, e-mail skellyj@unce.unr.edu or call me at 887-2252. You can "Ask a Master Gardener" by e-mailing mastergardeners@unce.unr.edu or call your local University of Nevada Cooperative Extension office. Check out many useful horticulture publications at www.unce.unr.edu.

• JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension.