If you have vegetables that are blooming but not setting fruit, you may have a problem with flower pollination. Ward Upman, Kansas State University Extension associate, says there are several possible reasons, and the reasons vary by species.
One condition that can affect several species at the same time is overfertilization. Too much nitrogen causes the plant to emphasize vegetative growth, and can lead to a delay in flower production and a decrease in fruit set among the flowers produced.
Squash, cucumbers, watermelon, and muskmelon can have other problems, as well. First, the early flowers on these plants are usually all male. The production of both male and female flowers becomes more balanced as time passes.
You can tell the difference between the two because only the female flower has a tiny fruit behind the blossom.
If you have both, have not overfertilized and still have a problem, make sure you have pollinators. According to Upman, you should look for the presence of bees visiting the plants. If you don't see any, try hand-pollinating several flowers. Use a painter's brush to transfer pollen from the anther of the male flower to the stigma of the female flower. If you get fruit on only those flowers you pollinated, you need more pollinators. Make sure you aren't killing them with overuse of insecticides.
Tomatoes are wind pollinated, so they are not dependent on pollinators. But they have another possible problem, which is temperature. Tomatoes normally won't set if the night temperature is below 50 degrees, due to sparse pollen production. They also won't set when nighttime temperatures are above 75 degrees and daytime temperatures are above 95, with dry, hot winds.
Here are some upcoming workshops and other events offered by Franklin County Penn State Extension, 181 Franklin Farm Lane, Chambersburg. Most classes take place at the Extension office and grounds.
To register or for information, call 263-9226 unless otherwise noted.
• Rain barrels: 9-11 a.m. July 12, clubhouse at Extension office, 181 Franklin Farm Lane, Chambersburg; learn the basics of storm water management, how to use harvested rain water and rain garden principles; $40, includes a rain barrel ready to install at home (or $10 for the workshop only; register by July 7.
• Using your own herbs: 8:30 a.m.-12:30 p.m. July 19; Visit the herb demonstration gardens; watch cooking demonstrations for snacks, appetizers, desserts and more; taste a variety of salad dressings using fresh herbs; make an herbal soap "scrubbie" using soap chips and herbs; and make a fragrant, moth repellent sachet. $15, space limited, registration required.
George Hurd is the environmental and resource development educator with Franklin County Penn State Extension. Contact him at 263-9226, Ext. 225 or email@example.com.