ph

when you water or fertilize, do you always get 20% runoff and toss that out or outside etc? dry pockets can cause issues. not getting enough runoff can cause buildup. This will cause volatile pH swings. wait for top 1" to dry and always saturate entire pot with 20% runoff. (small plant, large pot may require special attention, but can likely still adhere to this). if coco, just wait for top layer to change color, as it holds much less water than soil or peat-based substrate. if it hasn't been constantly wet, i'd go out of cycle and give it a solid irrigation with fertilizer... get 20-30% runoff, use that water anywhere else but get it away from root zone of your marijuana plant. After that, wait for it to get dry. if you've been watering more often than that, i'd wait for top 1" to dry, then give a little extra 30% runoff.. make sure to err on the 20% + .. don't have to go crazy. after that ~30% is fine, give or take a small amount, but to reset it, give a little extra. after that, it will be at a good equillibrium from top to bottom, regardless of roots existing there... each time you run that excess through, it resets it. the problems arise when it doesn't fully get saturated and/or some areas actually dry out where you cannot see. this'll be a major problem.