I've got some tweedie seeds with their second set of leaves just appearing. They are still very small seedlings, about 1/2" high at most. They've been under lights for weeks. I'm wondering if they would be better off beginning to see the light of day. I could put them outside for a couple of hours in the morning and gradually increase it to be all day, bringing them in at night until much larger.

So in short:

What determines going outside - number of weeks under lights, how many leaves have appeared? etc.

Thanks,

Ginny