1st picture made me think phosphorus deficiency, 2nd pic makes me lean towards calcium deficiency or lockout.

Hey Gruwee 👋 Brown spots showing up right at the start of flower are pretty common. Most likely causes are: Calcium deficiency (very common with Amnesia, especially under strong light) pH slightly off, locking out calcium/magnesium A bit of early flower stress as the plant shifts energy Check your pH first (soil ~6.2–6.5, coco ~5.8–6.2). If you’re not already using one, a light Cal-Mag supplement usually clears this up fast. Also make sure you’re not overfeeding — too much EC can cause similar spotting. If the new growth stays clean, you’re on the right track. The damaged spots won’t heal, but they shouldn’t spread once the cause is fixed. Amnesia is a bit picky, but she rewards you later 😉🌱

Hi .... I think it's a Cal-Mag deficiency........ Try watering with Cal-Mag and also check your pH and EC values again, and adjust them if necessary. Good luck!

Advanced calcium deficiency, not a magnesium deficiency.

Hi Buddy First, thank you for sharing the photos, they tell a lot. Good catch noticing this early — that already puts you ahead of the problem. What we’re seeing From the photos, the pattern looks like: • Irregular brown/rusty spots • Mostly on older fan leaves • Some interveinal discoloration • Leaf structure still fairly healthy (no major clawing or burn) This combination points very strongly toward a Calcium / Magnesium issue, especially common right at the start of flowering. ⸻ Most Likely Cause (90% confidence) 👉 Cal-Mag deficiency or lockout This often happens when: • Using soft water / RO / rainwater • Transitioning into flower (plants suddenly demand more Ca & Mg) • pH drifting slightly out of range • Feeding was fine in veg but not adjusted for flower demand It’s not uncommon in Amnesia — she’s a hungry, expressive plant. ⸻ ❌ What it is NOT (important) • ❌ Not pests (no bite patterns, no stippling trails) • ❌ Not heat stress • ❌ Not light burn • ❌ Not a disease or fungus So no panic, no sprays, no drastic moves. ⸻ ✅ What to Do (Simple & Gentle) Tell the grower this: 1. Add Cal-Mag • Start light (don’t overdo it) • Especially important if using soft or filtered water 2. Check pH • Soil: aim ~6.2–6.5 • Coco: ~5.8–6.1 Lockout often looks like deficiency. 3. Observe new growth • Damaged leaves won’t heal • New leaves should come in clean — that’s your success signal 4. No heavy defoliation yet • Let the plant use what she still can • Remove only fully dead leaves later Growers Love my friend and please remember this is just my humble opinion You caught it early, so you’re in a great spot. Keep observing and let the plant guide you and follow what she tells 🌱

This is the symptom of a Magnesium chlorosis. It’s a magnesium deficiency. It can come from different factors, like a lack of magnesium in the media but also too intense light.