Overwintering seedlings / plants in March
So I was later, very late in fact, to sow the seeds in regards to my first frost date in zone 6a, that is in PA. And I decided to grow the seedlings indoors and will eventually transplant them out in the garden bed after the last frost date. My question is that, since I only have one grow light and I need to use that now to grow new seedlings, annuals, what is the best way to make sure, after I remove these grown seedlings from under the light, that they do not die and survive until it is time to transplant them outside. I have read a bit about overwintering but can that be done only before winter sets it? What are my options now, to keep these seedlings, away from the grow light and still keep them alive.
Should I just stick them in the ground outside one day when the temperature is above 0C? Place them in the unheated garage? Our garage has no light access btw, so will that affect them if this option is viable?