Calbear,
I could be completely wrong, but from what know about horticulture in general, you are going to have all kinds of problems trying to switch from hydro to outside dirt. That is assuming you are going to grow bigger than a couple of inches or longer that a week or two the outside because very soon after that point you will have roots headed every where on the sides and bottoms of the block and you are going to stress the heck out of them planting them into dirt outside.
From what I've seen, read and heard in person, most outdoor growers will either germinate their seeds and immediately trans plant them into little pots of soil/dirt to harden and start their seedlings and then trans plant the well rooted seedling into the outside dirt, being as careful as possible to avoid damaging the roots or stressing the seedling, OR they will sprout the seeds directly into starter cubes like rockwool or oasis foam blocks or many of the commercial "rooting" plugs, then as soon as the plant is somewhere around 3" to 4" tall or 2 weeks old, then plant the starter medium directly into the small pot filled with soil and when they think they are ready, transplant them outside.
Whatever you do try to disturb the roots as little as possible! I would never try to remove a rooted seedling or clone from any medium except peralite!
If you clone or sprout in peralite, when it comes time to transplant, either into soil or into hydro, take your small pot full of peralite, submerge it in a deeper container of clean water just like you would use to water the seedling/clone until the top of the peralite is approximately an 1" below the surface of the water, then gently agitate the pot and watch the peralite begin to float out of the pot. Once you have dislodged as much of the peralite as will float out, continue to agitate the pot under water and GENTLY pull the seedling/rooted clone out of the pot and water filled outer container. Done carefully virtually all of the pearlite will come of of the roots and what little is left can just be buried in the soil or hydro medium along with the roots. (This technique was posted elsewhere by our friend Hick.)
Good smoking.