For my saw tooth oaks, I move them to the 3 gallon black containers (like a nursery has) and put them on the eastern side of my house beside the water hose. I water them all summer and then set them out in October/November. But, I suspect you could set them out now; but I would keep them watered this summer.
If they have green leaves now, I wouldn't plant them outside. All of the oak seedlings in nc, have had over 400 chilling hours ( between 32 and 45 degrees) to get them fully dormant right now. They need to be dormant right now to protect from freeze damage. I'd wait until the last frost date for your area or at least when you see the oak seedlings in the woods starting to leaf out.
Here's a link to the last frost dates https://content.ces.ncsu.edu/average-last-spring-frost-dates-for-selected-north-carolina-locations
I have a similar question - when can I transplant seedlings (or can I?) from one spot to another? We have a nice large white oak on our property that will basically be in the side yard once we build our house. It has dropped a fair amount of acorns and I have seen a few sprouts the last year or two, but I don't need another (eventually) big oak in that area of the yard. I want to have a few in what will be that back yard, and maybe even in the wooded area behind the house, which is primarily pines right now.
When is the best time, and what is the best way to transplant? Or am I better off picking up acorns next fall and starting them inside like rubline is? Or just pick up and plant them all at once in the Fall?
pir8rn - I transplant all the time. Anytime I see one come up, whatever time of year (usually in the summer when they are leafed out and I can ID) - I dig it up and put in a 3 or 5 gallon black nursery pot (whatever I have on hand); mix in some compost, or potting soil and keep watered through the summer. Then plant where I want to in the Fall.
While they're in this stage don't put them where the squirrels can get to them for they'll surely dig them up to get what remains of the acorn. I lost a dozen Chinquapin oaks some years back when I took the wire cover off the bedding box I sprouted them in because they were growing up against it (8" to 9") tall.
I always put them in pots outside in the fall with hardware cloth as a cover over the dirt. pot is 10 inch around i put a 10 innc circle of Hardware cloth in it. never had a problem with squirrels doing this and I dont have to water them until springtime and when I plant i just have to cut open the mesh. Chestnuts do the same way.