Autumn Care of Tuberous Begonias
When foliage begins to turn yellow, plants are preparing for their period of dormancy. At this time, water should be gradually withheld, but not omitted entirely. If grown indoors, move plants to a shed or onto a porch. Foliage will gradually die down and drop off. It is wise to remove foliage from plants before it begins to decay. At this stage, water should be withheld entirely. The main stem will eventually drop off, or may be carefully severed by hand. It should never be cut off at the point of junction with the tuber, or forcibly broken off. Tubers grown in garden beds should be dug with care and prepared for storage. Pot-grown tubers may be left in pots, with pots turned on their sides. They should be placed in a dry, cool place.
Experienced growers prefer to remove tubers from the pots after the plants have lost foliage and become completely dormant. Tubers may be washed so that all soil is removed before they dry, so that there is less danger of injuring the skin of the tubers and the larger attached roots. It’s essential that tubers be completely dry before storage. Spread them on a tray or flat in a place in the sun. After about two weeks of drying, they are usually ready for storage. Over winter, store in one-row-deep flats or trays in a cool dry place where temperature is maintained at 45-50 degrees F. In late winter or very early spring, the tubers should be uncovered and moved to a warm, light place so that the buds will begin to sprout and show color before planting.