Last autumn I stored several acorns in a 5-inch pot that was filled with potting soil and covered. I took the cover off 2 days ago to discover 7 saplings between 3 and 7 inches long. They are too big for the pot I was storing them in. Are they safe to transplant at this stage? What size pot should I transplant them in? How do I safely move them without damaging them?
Just an update: I transplanted them 13 days ago using both recommendations. First I slid the root ball from the pot by turning it upside down and gently pushing on it from a hole in the bottom of the pot. Once the root ball was free I dunked the root ball into a bucket several times until all the potting soil dissolved. From there I could unspool the taproots from each other which were thick enough to where none of the sprouts were damaged and all are growing well. Pictures from a week after transplant: