I've used Rapid Rooters before. Once the seed sprouts you only have a few days before the roots will start to grow through the plug. So you'll need to get them transplanted quickly. However, at that point they are way to small and fragile to go directly outdoors. You'll need to put them in some pots, ones big enough for them to grow for 3-4 weeks or until they have 5-6 good sets of true leaves. Something about 5 or 6" in diameter and at least 6" deep. When you do start to move them outdoors, do it slowly over a few days. Increase their time outdoors daily over 3-4 days so the plants can harden up and get used to their new environment.