Tuberous begonias are shade-loving plants that grow to a height of 6 to 9 inches and are native to the tropical areas of South America and Africa. The plants grow from underground tubers that are often confused as being bulbs. They produce flowers in the colors of pink, red, yellow and salmon. Begonias do not tolerate hot sun and prefer light morning sun or mostly shaded light conditions for best results. The tubers must be wintered indoors in areas that see frost or extremely cold fall and winter conditions.
Select a growing location that offers partial-shade light conditions and a well-draining soil. Wait to plant begonia tubers outdoors until the temperature reaches 64 degrees F. Cooler temperatures will result in a slower start for the plants.
Mix 2 to 3 inches of organic compost into the garden planting soil to increase the water drainage. Begonia plants will not tolerate standing water or extremely wet soil.
Loosen the soil and gently stick the tubers underneath without adding extra soil over the top. Make sure the indented side of the tuber is facing upward. Place the tubers 8 to 12 inches apart.
Water the begonia tubers immediately after planting. Keep the soil moist but not wet. Wet soil will increase the risk of root rot.
Fertilizer begonia plants once a month during the growing season with a general-purpose fertilizer.
Remove spent blooms from the plant but do not cut the foliage until it turns yellow in color. Begonias create food stores in the tuber through photosynthesis in the foliage.
Dig up the begonia tubers just before the first fall frost and let them dry for two to three days. Place the tubers in a cardboard box filled with peat moss. Store the tubers in a cool place through the winter months.