There are several reasons why healthy vegetable crops produce flowers and no fruit. Most squash, cucumbers and melons have separate male and female flowers on each plant. Usually, male flowers appear first in the season. Female flowers have a swollen area beneath the petals while male flowers have a narrow base. Check your plants to see if both flower types are present. If male and female flowers are present, observe the area for pollinators. If few to no pollinators are present, vegetables with separate male and female flowers may not produce fruit.
You can pollinate the flowers by transferring pollen from a male flower to the stigma of the female flower using a paintbrush. Mark that flower and notice if it is the only one that sets fruit. If this is the case the problem is likely a lack of pollinators.
Pollinator activity can be inhibited by the weather. Pollinators are less active on cold and rainy days. The use of insecticides can also harm pollinators. If using herbicides, apply them in the evening when the flowers have closed for the day.
High temperatures can cause some vegetable plants to drop their blossoms prematurely. Tomatoes will stop producing fruit in temperatures above 95 degrees F. Production will resume once the temperature decreases. Ensure plants receive adequate water during this time. Though nitrogen can promote vegetative growth, too much can inhibit flower and fruit production. Follow recommended rates for fertilizer applications.
