A question from a fellow grower:
its the end of the 3rd week of vegetation & a few of my plants lower fan leaves are turning yellow with brown spots on leaf tips.the yellowing starts at tips & in middle finger of leaf first, then the yellowing slowly heads toward leaf stem, brown spots only on tip portion of plant & run 1/3rd of the way to the stem of the affected leaves. thought it might be a PH problem but they are all 7 ph. next I think it may be a nitrogen deficiency, or a zinc deficiency. its not a heat problem the room is a constant 75 degrees, & i’m pretty sure its not an over-watering issue issue, but I need to know what it maybe & how to correct it as I am about 6 days from going to 12/12 hrs HPS600 for flowering for 8 weeks. I sure would appreciate all your help on this one as I am a total beginner at this & I value your opinion as the Professional grower & problem solver. FYI I grow in soil, not hydroponics.