There are lots of begonias out there these days, tiny wee ones that have delicate waxy flowers to enormous double ones (and even bigger) that catch your eye. They have always had a tendency to brightness, and these days you can get some that are so vivid they are almost described best as ‘electric’.
The brightest begonias are bought as tubers, and these are planted in sandy potting compost more or less as the same way as seeds. These are the biggest varieties, and interestingly the male flowers are bigger and more blousey than the female ones.
Tuberous plants should be lifted and overwintered in a frost free environment.
Fibrous begonias, those destined for bedding and hanging baskets, are sown in trays and potted on as soon as you get true leaves. They must be kept free from frost, so harden them off in May and plant them on in June.
All begonias have difficulty with fungal infections, especially where they are in damp and humid conditions, so always use free draining compost. A feed with tomato fertiliser always helps!