Diagnosis · 9 min read

Common rescue scenarios, diagnosed

Root rot, sunburn, etiolation, spider mites, mealybugs, fungus gnats, scale, cold shock, pot-bound roots, salt buildup.

Root rot and overwatering

Signs: yellowing lower leaves, a limp plant in wet soil, sour smell, brown mushy roots. Overwatering looks like underwatering because rotted roots cannot drink.

Fix: unpot, cut away every brown root with clean scissors, repot into fresh fast-draining mix in a pot with drainage, and water sparingly until new growth appears.

Underwatering

Signs: crispy brown leaf edges, drooping that recovers within hours of watering, soil pulled away from the pot wall.

Fix: bottom-water by standing the pot in a few inches of water for 20-30 minutes so the whole root ball rehydrates evenly.

Etiolation and leggy growth

Signs: long stretched stems, wide gaps between leaves, pale color, leaning hard toward a window. The plant is reaching for light it never got.

Fix: move to brighter light gradually over a week or two. Existing stretched growth will not shrink back, so prune it later and propagate the cuttings.

Sunburn

Signs: bleached white or tan patches on the side facing the light, usually with crisp dry centers. Distinct from disease because it is localized to the exposed side.

Fix: move out of direct sun. Leave burned leaves attached — they still photosynthesize around the damage. Reintroduce light slowly.

Spider mites

Signs: fine webbing in the leaf axils, tiny pale stippling across the leaf surface, dusty-looking leaves. They love dry air.

Fix: rinse thoroughly, raise humidity, apply insecticidal soap or horticultural oil weekly for three weeks.

Mealybugs and scale

Mealybugs look like white cotton tufts in joints and axils. Scale looks like small brown or tan bumps stuck to stems and leaf undersides, often with sticky residue below.

Fix: dab each one with 70% isopropyl alcohol on a swab, then treat the whole plant with horticultural oil. Re-check weekly — both are famous for coming back.

Fungus gnats

Signs: small black flies around the soil surface. Annoying but rarely fatal; the larvae feed on damp organic matter and mean the soil stays too wet.

Fix: let the top inch or two dry out fully between waterings, add yellow sticky traps, and consider a mosquito-bit (Bti) drench.

Cold shock

Signs: sudden blackened, translucent, or water-soaked patches after a cold night or a chilly ride home in a car.

Fix: move somewhere stable and warm, away from drafts and cold glass. Do not prune for a few weeks — wait to see exactly which tissue is dead.

Pot-bound roots

Signs: roots circling out of drainage holes, water running straight through, growth stalled.

Fix: once the plant is stable, move up one pot size only, tease the outer roots loose, and score the root ball lightly if it is a solid mat.

Salt and mineral buildup

Signs: white crust on the soil surface or pot rim, brown leaf tips despite consistent watering.

Fix: flush the pot with several pot-volumes of water in the sink, and ease off fertilizer until the plant is growing again.