sagging

Hi there! I recently upgraded to LEDs and in the mean time parted with the experienced grower I had partnered with... (boot straps up, organics incoming!) So last run (I didn't finish it) I noticed that the plants began to curl and stems became purple and very hard during the veg state...

Plant is Durban Poison. Sorry about sideways pics. I saved them correctly and they keep uploading sideways. Plant was Vegged for about 2 months and clipped for clones and repaired for 2 weeks Tent is a 36"x36"x72" Milliard Plant is 3 weeks into flower on 2-22-2016. Water Schedule Feb 2nd...