Apple trees

I planted 36 crabapple seeds on January 13th. I had them in a moist paper towel in the fridge for a few months. Some of them started to sprout, so I planted them in those little 1" square 6 pack thingies you buy bedding plants in. 6 of them are up already and are about 2 inches tall and have four true leaves. How long should I leave them in these before transplanting into something bigger? I finally got my growlight system built today and they are under there now.

i have never grown crabapple,bur here aare some url that may help u http://www.msue.msu.edu/msue/imp/moduf/07259501.html
http://cals.uvm.edu/ctr/oh/oh16.htm

Thank you for the links MaVieRose. From what I learned reading the links, growing crabapple trees from seed isn't a good idea, as they won't grow to be like their parents. That's okay with me though. Maybe I'll end up with a really good tree that produces great apples! You never know I guess. And the tree might have yucky apples too, but they will be welcome too. I want trees in a big way! LOL!

I still want to know when I should transplant them and when I should fertilize them. I've never grown anything from seed that amounted to anything, so I'm really green at this.

Joan,
the first url recommend to plant spring time. if i am not mistaken if u give the plant the right growing medium, it should come out ok. whenever i plant anything or mix soil for specific plants, i alway add some superphosphate in the mixture. superphosphate give the plant a good rooting media, and aid in flower formation too. during growing season, i use Miraclegrow 15-30-15 to water the plants twice a month. so far with both fertilizer, i have been able to grow nice plants. hope that help u. ma vie