Why do my cucumbers bloom without setting fruit?
This is a pollination problem. Cucumbers have separate male and female blooms on the same plant. For proper fruit set, the pollen must be transferred from the male to the female blooms. This is usually done by pollinating insects, primarily honeybees. Cucumber male flowers appear first, followed later by the fruit-producing female flowers. Caution must be taken NOT to spray with insecticides in early morning hours when pollinating insects are working. If pollen transfer does not take place, fruit will not set.