Poor Fruiting Vegetable Crops

The cool, rainy weather this spring and summer has led to disease problems on trees, shrubs, flowers, vegetables, and turfgrass. The cool, wet weather has also affected fruiting of some vegetable crops.

Vine corps, such as cucumbers, squash, muskmelons and watermelons, produce male and female flowers on the same plant. Male flowers furnish pollen for pollination, but never produce fruit. Female flowers have small, immature fruit at their base. Fruit set occurs when the pollen is transferred from the male to female flowers by bees. Most of the first flowers which appear on vine crops never produce fruit as they are predominantly male flowers. Fruit formation occurs as the number of female flowers increases during the growing season.

Fruit formation on vine corps is normally good by midsummer. Unfortunately, many gardeners this year are still experiencing poor fruit set. The cool, rainy weather has reduced bee activity, resulting in poor pollination. When not pollinated properly, the fruit begin to develop, then shrivel up and die.

While tomato flowers are self-pollinating, the cool, rainy weather has also affected fruit set on tomatoes. Flowers fail to set fruit when night temperatures fall below 55 to 60 F. The cool weather this spring was responsible for the lack of fruit formation early in the growing season. Fruit production hasn't increased because the rainy weather is interfering with pollination. As a result, fruit production on tomatoes has been drastically reduced.

The poor fruit set on the tomatoes and vine crops this year is mainly due to the cool, wet weather. There is little gardeners can do to help increase fruiting. These vegetables simply need several weeks of warm, sunny weather to produce a crop.

This article originally appeared in the July 21, 1993 issue, p. 120.