Flowers and fruit set of cucumbers and squash

It's time or nearly so when the vine crops will produce their first flowers only to have them drop off. What’s going on?

Cucumbers, squash, gourds and pumpkins produce separate male and female flowers on the same plant. The male flowers on cucumbers (right) appear about 10 days before female flowers and outnumber female flowers 10 to 1. Squash, gourds and pumpkins bear 4 to 10 male flowers for every female flower.

Learn to differentiate male from female flowers, be patient until the female flowers appear, and watch to see if bees are present to move pollen between flowers.

Male flowers are attached by a straight slender stem. The stem of female flowers bears a bulge, the ovary, which grows into the future fruit if pollinated and fertilized. In the squash photo above, the two male flowers (left and center) have just faded for the day and are clearly borne on slender stems. The female (still green) flower on the right will open tomorrow and has the swollen stem bearing the ovary.

Male flowers produce nectar and pollen and female flowers nectar only and in greater quantity than male flowers. Bees gather pollen in early morning and switch to nectar later. Flowers open early in the morning and close by noon or shortly after the same day never to reopen.

Note that the flowers of many other plants produce more nectar and are more attractive to bees than the vine crops. While both honeybees and bumblebees can pollinate vine crops, they can easily get distracted by other flower nectar and fail to pollinate your cucumber or squash flowers. If fruit set is poor you can remove male blossoms, tear the petals off to expose the pollen on the anthers, and hand pollinate.

Cucumber and squash flowers photo credit: Carl Wilson