You can start them inside now but they will die if put outside.

yeah I would think they would with 20 degree weather here in OHIO. When should I start them to put them out in mid-may

If that is your last period of frost... yes. For me spring starts around mid Feb but last frost date is mid March like the 15th. But we really get a freeze at that time. And so far we have hardly recieved any frost, maybe about a weeks worth. I already have Impatiens seedlings coming up. I hope this keeps up.