question about my soil

Hey Guys and Gals,
I'm a little worried about the soil I have my seedlings in. Its a mixture of third hyponex potting soil(no nutes), third of Jiffy-mix (soilless mix),third perlite. They have had 1 watering since sprouting and the soil is rock hard. Kinda hard to do the finger test for moisture but i can go by weight:) Just wondering if this is normal. Also I think I've made my first goof, I didnt fill my beer cups(16oz) all the way with soil so the seedlings are kinda stretching till they reached the tops of cups, so now i have some flouros 2" above them with a fan blowing on them. They are 2 weeks and starting ther second set of leaves. Do you think I should fill the rest of the cups up with soil? Or should I just be ready to transplant them too bigger pots within the week?
Thanks all
Peace

you can fill the cups up with soil and roots will grow out of the covered stem

dont cover leafs though

the plnats can get quite large in beer cups. at least 6-8 inches

Well I'd say my soil has settled about 3" from the top of the cups, Do you still think they'll go 6-8" in my cups? How bout my soil, is it suppose to get rock hard,how can I prevent this?
Thanks

When you say rock hard do you mean if you took your finger and tried to break the soil it won't break or what? I mean if you don't water soil get's hard and dry, that's what it does lol. I really don't understand what you mean.

use a fork to fluff it up when that happens and use a mulch. Mulch stops the soil from crusting.