I'm about 70 days into my gorilla glue autoflowers and I'm starting to get some purple in my leaves. Is this normal? I also have some yellowing or Worse on some of the leaves but I can't tell if that's because the plants are reaching the end of their life span. Even the stock on the one plants looks a little purplish. Let me know if i need to do something about this or am i ok?
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Do you know the runoff pH and PPM?
Most common darkening or purple colors come from cold stress. I'll add, fading or darkening happens naturally in some genetics late in flower. Especially if your media is drained of nutrients. This doesn't look like late flower yet so if there wasn't cold introduced recently it could be one of four deficiencies- Manganese, Zinc, Iron, Phosphorus (abundances of one of these can throw off color sometimes too, less likely IMO)
Do you know the ppm and ph of the medium? Not so much for the purple because a lot of strains do that, and more so in cold temps. Some of the leaves in pics show deficiency, but if your close to harvest I wouldn't go crazy making big changes. I'm very curious if you're medium ph is low.