Most squash (Cucurbita) plants produce many male flowers before female flowers appear. Because only the female flowers can develop into fruits, it's common for the plant to bloom for a while without setting any squashes. You can tell the difference by closely looking at the base of the flower. Male flowers have a slender stalk, and females have a swollen base that looks like a miniature squash. If your plants are producing female flowers, the flowers may be lacking pollination. Squash depends on honeybees and other insects for pollination. If your garden has few bees, fruit may fail to set due to lack of pollination. You could try hand pollination. Use a small brush or cotton swab to transfer pollen from the male flower to the female flower.