Maple Seedlings!

I usually pick up a handfull of seeds from a japanese maple I know that seeds regularly in fall, and I throw them into a 'soiled' flat to come up in springtime.
I happened to find that many seedlings come up under the tree the next spring. I collected many of these in a ziplock bag, with a wet paper towel in it, and transported these new trees home.
Well, it is ziplock bag time for the next month! I saw the first crop of seedlings break their shell on Feb 25.
I will wait another week for my first harvest.
1) I had better have time to pot them up fast!
2) I have to have soil too - something I am low on right now.
3) if I wait to long, the seedlings will lose growing time this year.
Let me elaborate on point 3. Seedlings (in general) grow only from the energy they have stored within them. They do not need any nutrients or anything from the environment. After the first quick burst the plants begin to utilize their environment to generate more energy and structures. If the seedling is disturbed during the first flush of growth, it will quickly recover and re-establish itself.
So damaging the maple seedlings roots by pulling it out of the ground, and then storing the plant in a plastic bag with 200 of its brethren for a couple hours while I finish my errands; won't harm the seedlings a bit - if I do it to the seedlings first couple of weeks of their life.

Grow a bonsai from seed kit

Grow your own bonsai from seed kits are ridiculous. This is because they give the impression that you can actually obtain a bonsai from seed quickly. The book which comes with the kit is very vague, an introduction to bonsai only. Seedlings don't need to be repotted, trimmed or wired.
What one needs to know about growing bonsai from seed is how to a) care for a seedling and b) develop good stock.
a) seedlings in crummy peat pellets are prone to drying out, or being drowned. This is because of the peat - it is either bone dry, or saturated. It doesn't spend much time slightly moist, what plants like. I suggest potting soil because people know how to keep plants alive in potting soil, or sand/gravel because the is what the seedling would want.
b) nebari and trunk girth are what is important about stock. The seedling has to be root trained by planting it on top of a flat surface, so its roots spread. Good nebari results in a greater trunk girth then a tree with poor nebari. But trunk girth is also obtained by unrestricted growth. This is why a bonsai from seed is a long term project.
Small bonsai from seed - 5 yrs
normal sized bonsai from seed - 12 yrs
large bonsai from seed - 18 yrs