i think its a strain problem!

so i ordered the auto flower pack from marijuana-seeds.nl, i have 3 auto berry, 3 auto white widow, and 3 low ryder 2 going

each plant is in a 5 gal bucket with individual airstones, the medium i am using is hydroton and rockwool cubes, a 400w hps bulb for lighting

im using GH grow micro and bloom according to their own charts, i change water and nutrients once a week according to the chart on the back of the GH bottles, the ph of the water is 6.5

all the plants are in their fourth week of life and showing the white hairs

the berry and lowryder are doing AWESOME! two of my white widow are not doin so well, after my water change last week the bottom leaves started to yellow so i chagned the water and added a bit of nitrogen thinkin it was nitrogen deficiency, it hasnt really gotten better and it doesnt really look like nitrogen deficiency anymore, ive posted some photos below! im wondering if anyone has any suggestions or maybe any experience with this strain being sensitive to nutrients

If you are growing hydro, I think you are, then you need to lower your PH to 5.5 to 6 range.

It could be a deficiency but if your other plants look OK then it might be a over nute problem, it's hard to tell from the pics... I would guess a deficiency myself

Check this out: http://www.mmjshopping.com/cannabis-college.php

It is a good source, sometimes too much info to process though. Let us know JR