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Brown spots on cannabis leaves – calcium deficiency or something else?
Week 5 of flower and I'm seeing brown spots appearing on fan leaves in the middle of the canopy. They start as small dots and spread outward. The edges of some leaves are also getting crispy.
Running coco/perlite with Canna nutrients. pH going in at 5.8-6.0. EC at 1.4.
Could this be calcium deficiency? Or is it something else? Pretty worried about my girls. 📸
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2 Comments
Expert Grower1mo ago
In coco, calcium deficiency is super common. Coco naturally locks out cal/mag. Add CalMag to every feeding — 2-5ml per gallon. Your pH range is good but make sure runoff pH isn't drifting below 5.5.
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Experienced1mo ago
Check for root zone pH too. In coco, salt buildup can cause lockout even if your input pH is fine. Do a runoff test — if EC is way higher than input, flush with pH'd water first.
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