Can sum 1 tell me why all the leaves on my plants are going yellow and have brown spots on am growing blue cheese in coco planted in 10L pots ph is 5.9 temps 73 day time 68 nite time and there under 2 600w hps and am use ionics nuts
looks like a cal/mg deficiency, from what i hear coco is very susceptible to this type of def. Gen hydro CalMg+ is supposed to work really well to clear this up. I just went through this, and it turned out all i had to do was up my pH to 6.3 and it cleared right up. If you look at a nutrient absorption chart it will show magnesium absorption goes up with pH, funny thing is when your plants pull the cal/Mg out of the solution the pH has a tendency to go down.
Classic K def... Too high of ph in coco is most likely your problem, you need to buffer the solution properly.. I feed in coco at around 5.5-5.8, no probs...