How to Grow Begonias
Begonia tubers may be started into growth from February onwards. The easiest way is to put them into shallow boxes containing a mixture of loam, leaf mould and sand.
As soon as the shoots of the tubers are about 2cm long pot them up in 15cm pots and place them into larger pots as the roots reach the sides of the pot.
Plant in full sun or partial shaded areas. The more access to sun, the more vibrant the colours will be. Feed once every two weeks with a high potassium up until the blooms begin to fade.
Make sure they are watered regularly during the summer and that the soil is not allowed to dry out. Begonias love moisture and will use up quite a lot during the hotter spells in the summer.
Lift tubers after flowering has finished and the leaves have begun to turn yellow. Store in a dry, cool (but frost-free) location over the winter. Store in soil that is only a little moist and keep this a little moist over the winter (with irregular watering) to keep the tubers from drying out.