seeds germ problem

I started germinating a batch of God Bud seeds a little over a week ago. I let them soak in water for 24 hours, then placed them in damp paper towel. most of the seeds cracked in the first 24 hours. and within 48 hours the small roots emerged. Over the next 4 days the roots have grown an absolutely minimal amount, the longest of which is not even half a centimeter. I have never seen such slow growth before. Is this common or should i be worried about my babies?

once they pop your supposed to plant them in your medium..

warm temps
darkness
moist soil / not wet

From what I've been taught, Ive been letting them germ until the roots were an average length of half an inch. Is this something i should stop? should i be planting them as soon as a root tip emerges, or as soon as the seed cracks? and if so, should i be introducing the light to them as soon as the plant sprouts from the medium?

every seed is different, some pop 1/2 inch some are a 16th of an inch..i haven't read any literature on leaving the seed in the water to wait for the root to grow.. that's why you plant it.

i just planted a seed with a 1/16th of an inch tap root and it sprouted today fine.

http://www.weedsthatplease.com/germinating.htm