leaf discoloration?

[swissmiss]

I'm growing 6 plants under a 450watt MH in an ebb n flow hydro system. They're doing great- three weeks old, but I noticed one plant had a slight yellow discoloration on two leaves. The one on the left, and the one of the right. The one on the left is the largest and probably easier to spot in the pictures. What does this mean?? Thanks! :rasta:

[swissmiss]

I checked the PH, btw, and it was normal at 6.5.

[swissmiss]

heeeere we go:

-indoor
-hydroponic
-organic soiless grow substrate
-bottanicare
-ebb n flow
-tap water
-6.5PH
-3 weeks
-nutes: Calmag/power plant, and liquid karma
-450 watt MH about 10 inches from plants
-70-65 degrees
-no humidity
-16light/8dark
-The room doesn't get hot, but there's an oscilating fan that circulates air

[Dreadscale]

I am not the one to give advise on this, but here are a couple of links, until you get an expert opinion.
Marijuana Plant Abuse (http://www.greenmanspage.com/guides/plant_abuse.html)
Identifying Plant Nutrient Deficiencies (http://gardening.about.com/od/gardenproblems/a/NutrientDeficie.htm)

[Weedhound]

you have NO humidity??? :eek: There's your problem.

Just kidding.

Your ph is too high for a hydro setup. You need to keep it between 5.6-6.2 See if doing that makes your problem go away.

Good luck.

[swissmiss]

Ohhhh, word. Cross your fingers it works!

[Cpt. Zissou]

Weedhound is right 6.5 is waaaaaaaaaaaay to high for hydro I'm in soiless and i stay under 6.3 at a minimum, and i like to keep it around 6.1 . I think lowering it is gonna help TONS! GL!