Begonias flower from early summer until fall frost, producing flowers in nearly any colour desired. They thrive in partially shaded areas of the garden, bringing colour to beds where few other flowers bloom. Saving the seeds from your favourite plants allows you to grow more plants or pass the seeds on to other begonia enthusiasts. Hybrid begonias will not produce seed true to the parent, while non-hybrid or heirloom plants produce true seeds. Experiment with your plants until you find the one that produces the best seed.
Cut off the seed pod once it begins to dry and after the stem has withered. Harvest before the seed pod splits open, as begonia seeds are very fine and scatter easily.
Place the seed pods in a small plastic container. Set the container in a warm, dry area for one to two weeks or until the pods begin splitting open. The container catches any spilt seed.
Empty the container out on a sheet of paper. Split open the pods and shake the seeds out on the paper. Remove the empty pods and any obvious non-seed material.
Fold the paper in half. Tilt it toward the container, allowing the seed to roll of the paper and back into the container. Shrivelled, unviable seeds and chafe remain on the paper as they don't roll.
Place a lid on the container then label it with the begonia variety, colour and year harvested. Store in a cool, dry place until you are ready to plant.
Try crossing your own begonia varieties. Pollinate female flowers by rubbing male flowers from the desired variety against them. If the pollination takes, the female flower's petal begin to drop and seed production begins.