Pot Bound

Has anyone every experienced their plants becoming pot bound before potting in larger pots?

I have 30 northern Lights plants and i didn't transfer them into larger pots for 2-3 weeks as i thought this would keep them smalled which it did but they are now in 15 ltr pots and turning yellow, with yellow speckels on the leaves and eventually the leaves are dying.

The 2 things i did which i also thought maye have affected them are as follows:

1. sprayed them whilst the lights were on
2. given them a small amount of nutrients to try and bring them round but i dont know whether that would have made the worse.

Would appreciate views on this. I have made the mistake on 2 seperate strains recently!!!!!!!!!!!!!

That is not from being root bound.

spotting can occur from droplets focusing light like a lens and buring, or by too heavy a nute spray, or by bugs, or by several differant difficiancies or excesses

post some pics or check the plant problem section

Yeah I wasnt even thinking that but if you drip some nutes on the leaves it will definately burn spots on your leaves.

Thanks for the replies guys, I'll post some pics tomorrow. I've flushed them and they seem to be doing a lot better, one problem I've had with 5 of them though is the leaves down the stem are very small and not really growing out from the plant, any ideas? P