If you have begonias you love, make them multiply. Here's how: Cut a leaf, and place it cut-side down into a container filled with 4 parts perlite and 1 part potting soil. Use a pencil or dibble to push soil around the leaf cutting (about 1/2 inch deep) and ensure good contact with the potting medium. Keep in a brightly lit, relatively humid environment out of direct sun, such as in a greenhouse or under a plastic cover. Mist three or four times a day; water when the medium feels dry. The leaves will take root, create shoots, and, when a few leaves grow from the shoots, they'll be ready for repotting.