here is an excellent thread on disease and problems with good photos. See if it helps. Could be your light but seems odd that the side leaves would burn and not the more sensitive tops which are closer.

Click on the link and check it out. International Cannagraphic Magazine Forums - The Complete guide to Sick Plants,pH, and Pest troubles!
Weedhound Reviewed by Weedhound on . 3rd grow 3rd time same problem Help me please third grow and she is pretty much on her last feed shes nlxnevilles haze and is being fed canna aqua flores, ive had no problems then wham come home from college and the same problem again......all previous grows have done this. i suspect it could be heat or light its a hydro gro in a wardrobe so space is tight. The light is 400w and might be a little close? ph is aroud the 6 mark so dont think its a defficisncy but im a n00b so what do i know, here are some photos of my plight: Rating: 5