NO VERTICAL GROWTH HELP?

This is my 4th grow first 3 was a sucsess,this time im having problems my plants look like they stopped growing vertical up,they stop at bout 2 r 3 inches with top leaves curling up to light.I cant figure out what this problem is,this is the 3rtd time on this grow iv started over and getting same results.For fist two weeks i only give a little water as nuts are in soil and the problem seems to happen after 2 weeks no growth,when i give nuts after 2 weeks its very little so its not nut burn either Help.Soil is All mix bio bizz,seeds Auto Crital Kush and growing indoors grow box approx 100cmx100cmx60cm coved with mylar.Top is not covered and light is 125 watt Cfl 6500k grow light.i have a osalting fan also for fresh air.I had same problem when i changed seeds and tried with easyryder auto.I have 2 more 250 watt cfls for when they start to flower so i have plenty of luments for just 2 autoflowers at time.light is on 20 on 4 off.someone sujested that it may be rooting as they are in very big pots and they are growing roots that maybe i should have stuck to a smaller pot as the root growth would be quicker thus the plants energy would be then able to be on the plant growth,seems like a good answer please anyone with an idea.Any advice of to what is happing im cracking up and thinking of packing it in.Ill attach pics gives better idea as to what they look like plant age 2weeks 3 days,i have left them in previous grow to go over 4 weeks and they wer still same size surley be then they should be much bigger and starting to go into flowering mode.cheers.

Raise the light some. If your soil has fert in it already, I wouldn't add any more, not for several weeks anyway. The size of the pot has nothing to do with it. It just seems like a good explanation, but the truth is a plant doesn't know what size pot it is in, therefore has no understanding whether to "put energy" into growing roots or the stem. A plant just grows. It doesn't know where it is.

if those are only 2 weeks old they look to be normal sized. little wrinkly but healthy color anyway.