Season

Hey Growmie, You're having a magnesium deficiency, you can tell from the light green or yellow coloring that's to show on the veins and edges of the lower & older leaves – this is one of the classic signs of a magnesium deficiency. You may also see red stems. Often with this deficiency, the magnesium is present, but the roots cannot absorb the magnesium properly due to an improper pH. Therefore it is very important to maintain the correct pH (and make sure the pH does not get too low/acidic) in order to avoid a magnesium deficiency. Hopefully, I answered your question and remember Happy Growing and Free your mind one puff at a time.