That was always a mystery to me because everyone says....
There's your problem, your resource. Stay away from cannabis forums, get your nose into a bonafide gardening forum and books. An exception would be at the Riddle3m site where seasoned growers will save you a lot of heartache. No bullshit over there. By invitation only.
If something seems popular at RIU, WATCH OUT.
Yes, plants need all the 12 essential elements from start to finish. Their size, mass and vigor dictates the amount and frequency at any given point in time.
Plant is stunted. Shit can it. Most times it just doesn't recover like it should.
Oh, and while you're at it, shit can the "cannabis specific" foods and go with quality foods like Peters, Schultz, Dyna-Gro, etc. Dyna-Gro for water culture, soil-less.