My plants had the same necrosis(burns/dead tissue) and some intervienal chlorosis as well. Cal Mag did the trick. I think Stinkyattic nailed this one.

-Jay
CaliJay Reviewed by CaliJay on . light stress ??? help n opinions welcome hello all , lil help cyclonite or others , lil background = in wtrfarms , room temp =73deg. , rh = 55% , ph = 6.0 , water in res n cells =65deg. , g/h 3 pt. nutes = ppm of 420-500 . 3 blueberry / 1 cotton candy x nycd . they just got their first taste of nutes n jumped like 4in. overnight . got like w/in 8-10in. of 1000w/ hps in cooltube . largest leaves on blueberry were affected the worst , tips not curled like nute burn , looks like light or heat stress i think ? cotton candy x Rating: 5