The best way to pollinate fruit trees is to let nature do it. Bees carry pollen on their little hairy bodies from the stamens on one flower to the pistil of another, pollinating the flower so that it develops seeds. Flowers can be self-pollinated with flowers from the same tree, or cross-pollinated with flowers from another tree of the same type and of the same or a different variety. The more distantly the two flowers involved are related, the more vigorous and better quality the fruit will be produced.
A bee house can be hung from a tree to attract bees. Do not use insecticide during the blooming season. This will kill the desirable insects that are attracted to the flowers as well as undesirable insects that are attracted to the fruit. Hang glue traps that resemble the fruit of the tree among the real fruit to rid the tree of the pest insects. Small containers of sweetened water can also be placed to attract bees to the trees.
Although some trees can self-pollinate, the most vigorous and healthiest fruit crops result from cross-pollination. Have two or more trees with the same kind of fruit but of different varieties present in the same garden to cross-pollinate. Choose trees that bloom at the same time. If there is room for only one tree of each type in the garden, multi-graft trees can be chosen that have branches of different varieties of the same type of fruit grafted into the rootstock. These trees can then self-pollinate. A branch from a different variety tree can also be put in a bucket of water near the tree to be pollinated by the bees.
If no bees are present to pollinate the fruit trees, the flowers must be pollinated by hand. This is more tedious than letting the insects do it, since it requires manually transferring the pollen from one flower to another. The pollen can be collected from the stamens of a different tree of the same type of fruit and transferred to the pistils of the flowers to be pollinated with a small paintbrush or a cotton swab. Individually pollinating each flower of a tree blooming with an abundance of flowers can be time consuming. Another way is to take a branch from a different tree and brushing it onto the branches of the tree to be pollinated.