Summer squash produces both male and female blooms. Typically the male blossom appears first to attract bees and flying insects. As insects visit the flower to gather nectar, pollen is collected on their legs and body. When the insect visits the female bloom, pollen is deposited, pollinating the flower. Within a few days, the fruit begins to swell and flowers drop from the summer squash. Without flying insects, pollination is unlikely to occur, unless you help the blooms out with hand pollination.
Examine the squash blooms to identity the male and female blooms. Male blooms appear on a slender stalk and contain several pollen-covered stamens. Female blooms contain the pistil that receives the pollen. Female blooms have a tiny squash at the base of the flower.
Brush the stamens in the male blossom with a soft brush. A painter’s brush, soft makeup brush or soft-bristled vegetable brush works well. Yellow pollen brushes free of the bloom and sticks to the brush.
Locate a female bloom and brush the pistil with the pollen-coated brush. The sticky end of the pistil collects the pollen, which then pollinates the fruit.
Repeat the process of gathering pollen from male blooms and brushing it into female blooms until all female blooms have been pollinated.