I have my begonias in a 8in pot how much water should I give them? should I keep them moist or dry ?
That depends on a lot of things. What kind of soil, what kind of begonia, weather conditions, etc. A general rule of thumb is to let them dry out "some" between watering but water well when you do. Some begonias seem to prefer never drying out (Soli-mutata for one) while some prefer it on the dry side (San Miguel seems to rot easily if kept wet). In winter while indoors you will probably want to keep them a bit drier than summer outdoors (once wet, they may not dry out quick enough indoors).
Make sure the pot size is not too big for your plants either.
Absolutely on the pot size! Never overpot them. Begonias all prefer some drying, except for the terrarium types. How dry is a matter of soil quality. Always include good drainage and use a light soil. Too heavy = death for sure, which is why many perish. During winter, they require less of everything unless you live in Tampa Bay, like I do, and begonias grow like crazy all year long, outdoors. Keep light levels strong (never full sun unless you live here etc..) Greg Sytch AB S Horticultural Correspondent
What kind of Begonia do good in Michigan Thank you!
You might want to start a new thread with a good subject line so you get more answers to your question. I suppose almost any kind of begonia should do well in Michigan if you treat it like they want to be treated. Was there any particular ones you are interested in? Rex, tuberous, canes, rhizomatous, etc?