Lots of flowers, but no fruit formation? Pollination Tips in Vegetable Gardening

You might notice a lot of flowers on your squash plants and think you are going to end up with a lot of produce. Then weeks go by and your flowers are not turning to fruit. If this has happened to you, especially in squash (zucchini), cucumbers, and pumpkin plants, it is because these plants are considered monoecious. Monoecious plants can have male and female flowers in separate structures on the same plant. This means flowers will either be male or female. For pollination to occur, you need a fully developed male flower which produces pollen to be exposed to the female flower. This happens naturally through our insect pollinators.

If you are in an area with few pollinators or your plants are indoors, you can actually hand pollinate your plants. The first task in the process is to identify the male and female flowers. A female flower has a grape-sized swelling at its base; after pollination, the swelling increases in size and develops into a fruit. A male flower has thin filaments called stamens at its center. Use a small paintbrush or cotton swab to collect pollen from the stamens, and gently brush the pollen into the center of female flowers.

Another common issue with monoecious plants you might notice is male and female flowers occur at different times or you have all male flowers. As these plants develop, the male flowers bloom about 10-14 days before the female flowers. The plants naturally produce more male than female flowers, especially at a younger age. If the plant has ideal growing conditions, it will produce plenty of female flowers as it matures, equally the ratio of male to female flowers. In periods of hot weather or stress, a plant might only produce the male flowers. Since female flowers take more energy to produce, a plant suffering from inadequate nutrition or stress from weather will not use it’s energy to create female flowers. Make sure your soil is healthy and the levels of nitrogen and potassium are ideal. These two nutrients are vital for encouraging female flower formation.

Most of the stress in plants come from weather conditions out of our control such as too high of temperatures or not enough rain. You can help by providing your plant adequate water, nutrients, space, light, and healthy drainage. If pollinators are an issue in your area, you can always plant native pollinator friendly species to help entice them to come to your garden. However, if you still notice little fruit development after having male and female flowers, hand pollinating is simple to do if you have the time!