Diagnose a Plant Problem
Most houseplant symptoms have several possible causes, and the treatments are often opposite. Start from what you can see and work through the causes in order of likelihood.
Brown, crispy leaf tips
Brown tips are usually low humidity or mineral build-up from tap water — not thirst. Switch to filtered water, raise humidity, and flush the pot to leach out salts.
Most likely: Low humidity · 6 causes covered
Work through it →Root rot
Unpot the plant now. Healthy roots are firm and pale; rotted roots are brown, mushy and smell sour. Cut every rotted root away, repot into fresh dry mix, and do not water for a week.
Most likely: Overwatering · 6 causes covered
Work through it →Leaves turning yellow
Overwatering causes yellow leaves far more often than anything else. Push a finger two inches into the soil: if it is damp, stop watering and let it dry out.
Most likely: Overwatering · 7 causes covered
Work through it →Wilting, yellowing — but which cause?
Feel the soil two inches down and squeeze a leaf. Damp soil with soft limp leaves means overwatering. Dry soil with crisp papery leaves means underwatering.
Most likely: Overwatering · 4 causes covered
Work through it →Drooping or wilting leaves
Check the soil before watering. Dry soil means thirst — water and it recovers in hours. Wet soil means root rot, and watering again makes it worse.
Most likely: Thirst · 6 causes covered
Work through it →Solid leaves with no holes or splits
Fenestration needs bright indirect light, plant maturity and something to climb. Move it within 3–5 ft of a bright window and give it a moss pole.
Most likely: Not enough light · 5 causes covered
Work through it →Small black flies around the soil
Fungus gnats breed in wet topsoil. Let the top 2 inches dry between waterings, add yellow sticky traps for the adults, and treat the soil with BTI to kill the larvae.
Most likely: Consistently damp topsoil · 4 causes covered
Work through it →Long bare stems, widely spaced leaves
Legginess is almost always insufficient light. Move the plant closer to a window or add a grow light, then prune the stretched growth — it never re-compacts on its own.
Most likely: Not enough light · 5 causes covered
Work through it →Fine webbing and stippled leaves
Isolate the plant now — spider mites spread fast. Shower it thoroughly, then treat with insecticidal soap or neem every 5 days for three weeks to catch each new hatch.
Most likely: Hot, dry air · 4 causes covered
Work through it →The two checks that solve most problems
1. Feel the soil, two inches down
Not the surface — the surface dries within a day of watering and tells you nothing. Damp at two inches means stop watering. Bone dry means water thoroughly. This single test resolves the majority of yellowing, drooping and wilting cases.
Overwatering vs underwatering →2. Be honest about the light
At midday, could you comfortably read a book in that spot without a lamp? If not, it is a low-light position no matter how bright the room feels. Light intensity falls off with the square of the distance from the window.
How to measure light →