Someone posted (Weezard I think) that it takes a few extra weeks to finish them when using LED. Considering what you said about watering (and I have heard many others say) we could add some extra perlite (or whatever your soil amendment of choice) and make sure there is plenty of circulation in the grow box. That should increase the watering frequency which should improve growth.

It seems to be pretty well established that an ambient air temp of 85f is the optimal temperature for most strains to flower. Therefore if we set thermostats on our exhaust fans to maintain that temp that should also improve growth. Since CO2 can be better used at the higher temps, a real basic CO2 augmentation might also help. While the CO2 levels outdoors are just over 388ppm now, indoor the levels may be significantly higher (especially in the winter when I am brewing!) There for a slight but steady intake of this extra CO2 could also improve growth.

Anyway those are some ideas I have been thinking about for adjusting our grow rooms to LED. If we try all these things and the two week delay remains, I spose we could experiment with a timer and a infrared source (I bet Weezard already has?) If all else fails, maybe we can just veg less and switch to 12/12 sooner?
SupraSPL Reviewed by SupraSPL on . LED grow lights... input please. Hello guys, I'm exchanging eMails with a representative from a LED company. I asked him if they could produce a custom light for growing, and here's what he told me: Our options are as follow: 940nm, 850nm, 660nm, 630nm, 610nm, 590nm 570nm, 530nm, 510nm, 470nm, 460nm, 400nm and a total of 64 LEDs in the bulb. Rating: 5