they have to root...during root formation, the plant remains dormant, basically, then after roots take hold and uptake nutrition form medium...they start growing again. NO nutes until they have 4-5 true sets of leaves, which in turn means they have a strong enough root system to sustain the plant...start with 1/4-1/2 nute strength for a week to acclimate plants to nutrient regimen. goodluck

lw

And, I agree with Z...clones root much better under fluorescent light. I found this out by trial and error...leaving my aero cloner in the veg room under HID contributed to my clone success rate dropping drastically.
I know for sure, because as soon as I put cloning op inroom wioth fluoros...all the roots and success % came back up^