It's sometimes joked that home gardeners will break into their neighbors' homes in midsummer, not to take anything, but to leave buckets of zucchini squash. But squash is not always as productive as you might think, as a number of gardeners have found out this summer. In order to understand why you may have had a light squash harvest, it's helpful to know something about the plant family to which squash belongs.

Squash belongs to the cucurbitaceae family, which includes cucumbers and melons. Often called "cucurbits", these plants have a very unique flowering habit. They bear two kinds of flowers, male and female, both on the same plant. To have fruit set, pollen from the male flower must be transferred to the female flower. The pollen is sticky, and cannot be carried by the wind. Instead, honeybees must transfer the pollen. Other insects may pollinate cucurbits, but not as reliably as honeybees. Farmers who grow cucurbits place hives of honeybees in their fields to insure that pollination takes place. But in some home gardens, where bees may not be common, fruit set in squash, cucumbers, melons and similar crops may be very poor or even non-existent. You'll know you have a pollination problem when your squash fruits grow 2 or 3 inches long, then shrivel and dry.

One way to improve pollination is to encourage more honeybees to visit your garden. Growing a variety of annual and perennial plants that bloom throughout the summer is a good way to attract honeybees and other beneficial insects to your garden. Flowers make attractive and useful borders around vegetable gardens. Also, to avoid killing honeybees, use insecticide sprays on your cucurbits only when necessary.

When the bee population in your garden is too low for good fruit set, you can substitute for the bees by pollinating by hand. Hand pollination is a tedious chore, but if you really like squash and there are no bees in your garden, it's the only way you will be able to harvest a crop. You can use a small artist's paintbrush to transfer pollen, or you can break off a male flower, remove its petals to expose the pollen-bearing structure, and roll the pollen onto the stigma, the structure in the center of the female flower. The pollen is yellow and produced on the structure in the center of the male flower. Flowers open early in the day and are receptive for only one day. When hand pollinating, it's important to use only the freshly opened flowers.

You can easily recognize a female cucurbit flower because it has a miniature fruit on a short stem at the base of the flower. Female squash flowers are much larger than the female flowers on melon and cucumber plants. The male flower is easily identified by its long, slender stem.

It's commonly thought that squash, melons and cucumbers will cross-pollinate, but it is not so. The female flowers of each can be fertilized only by pollen from that same species. However, varieties within each species will cross-pollinate. For instance, zucchini squash will cross with crookneck and acorn squash; straight eight cucumber will cross with lemon cucumber, and so on. When you grow more than one variety of a particular cucurbit in your garden, they will readily cross. Seed saved from such plants will produce fruit that are different from either of the original parents.