Funnily enough, I was inspecting my sunflowers this morning. They are now about six inches tall and should be blooming by July.
My tomato seedlings are doing well, two to four inches high. When do you think I should put them in the growbags?
You should transplant them when two true leaves have formed. Are the seedlings currently in a propagator? If I were you, I'd transplant them to 9cm pots rather than a growbag, but it's up to you. Any chance of some pictures as they progress?