Begonias may be grown from seed or cuttings. The seeds are very tiny, making it difficult to plant sparsely. The seedlings generally sprout in bunches that must be thinned when an inch or so tall. The seeds germinate in about fourteen to twenty days under suitable conditions. Begonia seedlings (small plants) are relatively inexpensive so many people choose to buy them from their local garden shop rather than trying to start the tiny seeds.
Begonias are annuals that must be re-planted each year. They do not tolerate cold weather and will die with the first frost in the Fall. However, it is possible for the plants to reemerge in areas with mild winters, but don't count on it.
You should plant them outdoors in pots or your garden in the spring after all danger of frost has passed.
There are many varieties of Begonias with different colors but a shocking red is perhaps most common. Various varieties will do well in full sun or shade. They should be planted in a loose, fertile soil that drains well.
For continued blooming, you should remove dead flowers, leaves, and stems at least every two or three days. Occasional light pruning will not hurt the plant and will help maintain a compact, attractive shape.
Watering and Fertilizing
When watering, soak the base of the plants thoroughly, then allow the top three inches of the soil to dry before the next watering.
Begonias benefit from a once a month addition of a general purpose fertilizer (5-10-10).
Begonias are attractive to snails, earwigs and whiteflys. We believe the best deterrent to snails and slugs is food grade diatomaceous earth (DE) pronounced "dia-toh-may'-shus", which can be difficult to find but is generally available at most health food, natural food stores and Amazon online. Be sure to get "food grade" not "pool". The pool product used to clean swimming pools has harmful additives and can harm your plants and wild life. Also be careful of DE sold in garden shops which generally contains harmful additives to speed up the effectiveness of the product. If it does not specifically say "food grade", do not use it. Food grade diatomaceous earth is totally harmless to you, your pets and all mammals. You can eat it if you want (don't know why you would want to).
It kills crawling insects like roaches, snails, fleas and ticks by dehydrating them. It has some drawbacks such as it must be reapplied after rain and it takes several days to rid your garden of snails but it works and is safe.
As a sidenote...if you ever have fleas invade your home, food grade DE is the best solution. It takes two to three weeks to eliminate fleas but it will definitely get rid of them without using any poison.
Earwigs and whitefly's can be controlled to a degree by spraying the foliage (especially the underside of leaves) with a moderate stream of water from a hose.