Leaf Colour:
Veins of Leaves Stay Green
Brown or Dark Spots
Leaf Symptoms:
Lower Leaves / Older Growth Affected
Veins of Leaves Stay Green
Spots
Mottling / Mosaic
Spots on Leaves?: Yes
Quick Summary: Managing pH is crucial for cannabis plants to be able to take up nutrients through their roots. When the pH around the roots jumps up and down, it can stress the plant and cause brown spots to appear on the leaves. Spotting on the leaves as a results of pH fluctuations is more common in hydroponic setups (where the pH tends to go up and down), but it is possible it can also happen in soil. This seems to often happen when the pH swings too high.
Problem: Certain leaves on the middle or lower parts of the plant show tan or brown spotting
Solution: The main way to fix this problem is to fix the pH problem that caused the spotting (more info below). The leaves that are effected will not recover, but once you fix the issue, the problem should stop spreading to other leaves.
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