Overwatering - the #1 cause of all plant deaths, not just marijuana, in plants cared for by man. Until I joined RIU I would not have guessed that overuse of fertilizers was probably a real close #2. Too many years guerrilla growing in the desert SW. I would carry the sweet green juice (water with Miracle Grow) for long distances to make sure my plants did not "starve". Little did I know when I was younger that the mountain ranges in the west Texas/southern NM regions were rich in dolomite, lithium, silica, magnesium and more.
The result a few times was distorted plants on my return visit. It only took a few times to deduce that the fertilizer did not help and did harm. I mixed according to instruction. Then an older grower (I started in 1964 and was 15) told me to never feed a plant the recommended feeding as most were developed using soilless methods. Probably coco or who knows?
I have encountered far more problems with nutrients than without. Big nutrient feeds are ridiculous as the plant is surely not using every one of the nutrients you supply in the amounts you're supplying even at best. I finally snuck some soil samples into a NMSU ag lab as a freshman in 1968 only to find the report stating "Nitrogen supplementation recommended for heavy vegetating crops early in crop, potassium and potash not recommended except for heavy flowering and fruiting species such as commercial flower and large crop vegetable".
Couldn't ask about pot and the USMC intervened when I flunked my first semester stoned and playing in a band. Go figure. But later when I was out I recalled that and have used very little K or P except one reduced strength feeding during bloom and only when clearly indicated. My weed is not just good but great. When your adult child raves about it and comes back for grow and harvest advice you are doing something right.
