If it's going to be more than a few days, they would probably be better off out of the tiny cells. You could transplant them into larger pots, like 4-inchers. I often do that with plants that I buy if I am not going to put them in the ground for a while.

I'd definitely advise transplanting them to larger containers without delay. Perennials are more forgiving, but annuals can suffer badly from being rootbound, in my experience. It will compromise their vigour and growth, and they may start to flower whilst still small (which can put paid to much more leaf and root growth).

Well, I would normally go the transplant route...but we are talking about being 2 weeks away from my last frost date and 2 full flats worth of lobelia. That is a lot of time, work, soil, pots and space for 2 weeks. Especially if there is a good chance that they can withstand a light frost with protection. I just don't know if they can. Right now they are in a cold frame. But that is more protection than a sheet or blanket. But if I transplant them, they won't all fit into the cold frame. Kay.

As an experiment, I planted lobelia in pots last fall to see how much cold they would tolerate. I had some in pots out in the open and some in a pot on my front porch, next to the brick wall and under shelter. The ones on the porch hung in there just fine until temperatures dropped into the low twenties. (I did not cover them.) If you are willing to take the risk of losing them, put them in the ground and keep them covered with cloches (bottles, plastic boxes, etc. will do) on nights that frost or freeze are predicted. They are cool weather plants, so you MIGHT win the bet. Remove the covers during the daytime. This sounds like alot of trouble too, huh? I think your only other choice is to pot them up into larger containers. It's messy, but you can probably do it complete in less than an hour. Cover your table with newspaper or do it outside. That will help with clean up.

Thanks all. I think I will take the one that look the most unhappy, and plant those, resrerving the cells that seem content for later planting. If they seem to be holding well for the next week or so, I will plant the rest. Kay.