You can plant them in other pots until they are bigger or you can transfer them to your garden with some additional protection. I mention this part because although my local slugs with a shell (forgot their common name) are not supposed to be eating live plant seedlings (only dead plant material), I seem to be losing several seedlings that I had been watching while they start and grow directly in the garden.

I can't say it's those slugs for sure but something out there, is still eating the live plants, and I've seen slugs hanging around!