If you aren't transplanting them to the outside garden, that makes it easy. Leave them outside if the temp will be 40 or higher, bring them inside if it will be any cooler than that. Most plant specialists will say leave them out at anything over 36 or 37, but that's cutting it too fine for me, so I'd say 40.
I just got tired of having all these little pots of starts in my house, so I transplanted them out to my garden yesterday. Normaly they would have been outside a week ago, but this has been a long, cold spring. So there's petunias, roses, and geraniums out there--so far.
at 11:36 AM on Apr. 20, 2009