How do I increase the flowers on my begonia house plant?
You cannot force flowers with fertilizer and repotting actually discourages flowering. If you haven’t pruned back your Begonia, that’s a good place to start. Cut the stems back by about a third. This may not produce more flowers right away, but it will make for a more compact plant. Most importantly, you must provide several hours a day of direct indoor sun. It really should be right on a south-facing windowsill, not several feet away. Light is the key to plant growth and flowering. If a plant does not get enough light, no amount of fertilizer will make a difference. If the light is good, then you can fertilize monthly at half strength.