... it's much better to put them through transplanting stress as many times as you can ... hold on, no it's not.Yes you can move them into soil, however I would personally use a sterile soilless potting mix like coir or peat moss, then transfer to soil after a few weeks.
Maybe if you don't know how to transplant. It may surprise you, but a lot of people experience no "transplanting stress" at all.... it's much better to put them through transplanting stress as many times as you can ... hold on, no it's not.