Why is my Afghani Strain of Cannabis Yellowing so much at 28 days?

47w
1:57
Description

Yellowing Afghani Strain of Cannabis. http://juicedcannabis.tip.me One plant in vegetative stage, one in flower in at 16 days, and one in flowering at 28 days. Is the 28 Day Afghani going yellow too early? The trouble has to be in the feed mix... I still need to get a PPM Pen that can measure the concentration of fertilizer in the water I'm feeding the plants with. Even the manual method of setting the PH of the water is pretty sketchy - and many times I guestimate instead of actually testing the water. Grow Room Improvements Getting my new medical cannabis grow room started has been a big investment. Now that I have it up and going - I want to improve and fine-tune the procedures, and get my vegetative plants of the best strains of medical cannabis for juicing raw plant in the flow of regular new plants entering the flower chamber, and one plant coming out each day for juicing. The early yellowing of this Afghani Plant at 28 Days of Flowering suggests I need to improve my ability to provide the correct concentration of nutrient at the ideal pH... So I'm studying different pens, testers and greenhouse solutions for better plant feed monitoring - especially since I want to graduate to a fully DWC grow. Comparing Strains of Cannabis, best cannabis strains, strains of medical marijuana, top 5 medical marijuana strains, strain review, afghani