Indoor Lemon Tree: Multiple Stressors Require Integrated Approach

Symptom Breakdown

• Brown/rust patches on stems: Could be scale insects, sunburn through window glass, or nutrient deficiency.
• Leaf drop + yellowing: Classic underwatering or root-bound stress.
• Tiny green bugs + webbing: Aphids (green) + spider mites (webbing).
• New growth continuing: Tree has reserves but is declining.

Priority Actions

1. Repot: Move to next size pot with citrus mix. Loosen circling roots.
2. Water correctly: Thorough soak until drainage; then wait until top 2 inches dry. No standing water in saucer.
3. Treat pests: Spray 100% pure neem oil (not "neem oil extract") weekly for 3 weeks, covering all surfaces. Neem is fungicide, miticide, and insecticide.
4. Fertilize: Slow-release citrus fertilizer (high N, with micronutrients) after repotting recovery (2–3 weeks).
5. Light: Brightest window; supplement with grow light if <6 hrs direct sun.

Monitoring

Leaf drop should stop within 2 weeks of consistent care. New growth should be deep green. If rust patches spread, scrape one—if it's scale, you'll find insects underneath.

Consistency is key. Indoor citrus cycles between stress and recovery based on your care routine.