Find out why your plant leaves turn yellow, brown, spotty, curled or droopy, with the most likely causes and what to do about each.
Pick the symptom that best matches your plant, then see which cause fits. Start with the simplest causes (watering, light and drainage) before reaching for sprays or fertiliser.
Yellow leaves Brown tips or edges Brown or black spots White powder on leaves Curling or distorted leaves Wilting or drooping Holes or chewed leaves Sticky leaves or tiny insects Flowers or fruit drop, or no fruit Tall, thin or slow growth
How to tell: The whole older leaf turns an even pale yellow, and growth is slow. Common in pots and in plants that are fed rarely.
What to do: Feed with a balanced fertiliser at the label rate. New growth should look greener within one to two weeks.
How to tell: Only one or two of the lowest leaves yellow now and then while the rest of the plant looks healthy.
What to do: Nothing to fix. Remove the old leaves to keep the plant tidy.
How to tell: The soil stays wet for days, may smell sour, and leaves feel soft. The plant may droop even though the soil is wet.
What to do: Let the soil dry out, empty the saucer and check the drainage holes. If roots are brown and mushy, repot into fresh, airy mix and trim the rotten roots.
How to tell: The new leaves are yellow but the veins stay green. Often linked to waterlogged soil or soil that is too alkaline.
What to do: Improve drainage and water evenly. Use a fertiliser that contains micronutrients, such as a chelated iron product, following the label.
How to tell: New growth is pale and small, and the soil is damp.
What to do: Water less and make sure the pot drains freely.
How to tell: The plant is also stretched and leggy, and growth is slow.
What to do: Move it to a brighter place. Increase light gradually so the leaves do not scorch.
How to tell: Wet soil with roots that are brown and mushy, or roots circling tightly with almost no soil left.
What to do: Repot into fresh mix in a pot with drainage holes, trimming rotten roots. For a root-bound plant, move up one pot size.
How to tell: The tips are dry and crisp, the soil is dry for long stretches and the pot feels light.
What to do: Water deeply until it drains out, then keep a steady routine.
How to tell: Common on calathea, ferns and other tropical houseplants, especially in air-conditioned rooms.
What to do: Group plants together, avoid vents and fans, and use a tray of damp pebbles or a humidifier.
How to tell: There is a white crust on the soil or pot rim, and the edges look scorched.
What to do: Flush the pot with plenty of plain water, let it drain, and use less fertiliser. Use rain or filtered water if tap water is very hard.
How to tell: Brown or bleached patches appear on the leaves that face the sun, often after the plant was moved.
What to do: Move to bright shade or filter the strongest midday sun, and let the plant adjust gradually.
How to tell: Round brown or black spots, often with a yellow ring, that spread in warm, wet weather.
What to do: Remove affected leaves, water at the base, space plants for airflow and avoid wetting the leaves. If it keeps spreading, use a fungicide labelled for your plant, following the directions.
How to tell: Small, angular, water-soaked spots that turn dark and may fall out, often after rain or overhead watering.
What to do: Remove affected leaves, avoid overhead watering and do not handle wet plants. Rotate crops and use clean tools.
How to tell: Pale, papery or tan patches only on leaves that get the strongest sun.
What to do: Give some shade in the harshest hours. The damage will not heal, but new leaves will be fine.
How to tell: Fine speckles or silvery stippling, sometimes with fine webbing under the leaves.
What to do: Rinse the undersides of leaves with a strong spray of water, repeat every few days, and use insecticidal soap if needed, following the label.
How to tell: A white or grey powder that rubs off, mostly on the top of the leaves. Common on cucumber, pumpkin, rose and okra in humid weather.
What to do: Remove badly affected leaves, improve airflow, avoid crowding and water the soil rather than the leaves. If needed, use a fungicide labelled for powdery mildew and avoid spraying in hot midday sun.
How to tell: Small white, cottony clumps in leaf joints and under leaves, sometimes with sticky residue.
What to do: Dab the insects with a cotton bud dipped in rubbing alcohol, or wipe them off, and repeat weekly until they are gone.
How to tell: New growth is curled or twisted, and you can see tiny insects or sticky residue on the undersides.
What to do: Check under leaves, wash pests off with water, and use insecticidal soap or neem oil if they return, following the label.
How to tell: Leaves curl inward during the hottest part of the day and relax by evening.
What to do: Water deeply in the morning, mulch the soil, and give afternoon shade or a windbreak.
How to tell: Leaves are dark, cupped and distorted. Herbicide damage appears suddenly after spraying nearby.
What to do: Stop feeding for a few weeks and water well. For herbicide drift, rinse the leaves and wait, because new growth is usually normal.
How to tell: The soil is dry and the pot is light. The plant perks up within hours of a good watering.
What to do: Water deeply until it drains out. Mulch the soil and check the plant daily in hot weather.
How to tell: The soil is wet, leaves droop and yellow, and roots are brown and mushy.
What to do: Stop watering until the soil dries, improve drainage, and repot with fresh mix, trimming rotten roots.
How to tell: The plant wilts in the afternoon sun and recovers by evening, even though the soil is moist.
What to do: This is usually temporary. Give afternoon shade and keep soil evenly moist.
How to tell: Tomato, chili or eggplant wilts suddenly and does not recover, although the soil is moist. A cut stem placed in water releases a milky ooze.
What to do: There is no cure. Remove the plant and its roots, do not compost it, and avoid planting the same family (tomato, chili, eggplant, potato) in that soil for several seasons. Use resistant varieties and clean tools.
How to tell: Ragged holes, dark droppings on the leaves, and damage that appears overnight.
What to do: Pick them off by hand, preferably in the evening or early morning. A biological control called Bt can be used on leaf-eating caterpillars, following the label.
How to tell: Irregular holes with shiny slime trails, worst after rain and on seedlings.
What to do: Go out at dusk and collect them, remove hiding places and put barriers such as copper tape around pots.
How to tell: Pale, winding tunnels or blotches inside the leaf.
What to do: Remove and bin the affected leaves. Keep the area free of weeds and check new leaves often.
How to tell: Rounded bites along the leaf edge, and you can often see the insects by day.
What to do: Pick them off, use fine netting over young plants, and encourage natural predators such as birds and spiders.
How to tell: Clusters of small green, black or yellow insects on new shoots and buds, with sticky honeydew. Ants are often present.
What to do: Wash them off with a strong spray of water or wipe them away. Use insecticidal soap for heavy infestations, following the label, and control the ants.
How to tell: Tiny white flies that flutter up in a cloud when you shake the plant.
What to do: Rinse the undersides of leaves, and use yellow sticky traps. Insecticidal soap can help, following the label.
How to tell: White cottony clumps (mealybugs) or small brown bumps on stems (scale), with sticky residue and sometimes black sooty mould.
What to do: Dab with a cotton bud dipped in rubbing alcohol, or scrape scale off gently, and repeat weekly. Wipe away the sooty mould with a damp cloth.
How to tell: Flowers and tiny fruit fall off during hot spells or after long dry gaps.
What to do: Water evenly, mulch the soil and give afternoon shade during heat waves.
How to tell: Plenty of flowers but little fruit, common on cucumber, pumpkin and in sheltered spots.
What to do: Hand-pollinate by moving pollen with a small brush, and plant flowers nearby to attract bees.
How to tell: Large, dark green leafy growth with few flowers.
What to do: Stop high-nitrogen feeds and switch to a fertiliser higher in phosphorus and potassium once flowering starts.
How to tell: On tomato, chili and pepper, a dark, sunken patch on the bottom of the fruit.
What to do: It is mainly caused by uneven watering, which stops the plant taking up calcium. Keep soil evenly moist and mulch. Adding more calcium rarely fixes it alone.
How to tell: Long, thin stems with wide gaps between leaves, and pale leaves that lean towards the window or sun.
What to do: Move to a brighter spot. Pinch or prune leggy stems to make the plant bushier.
How to tell: Roots circle the pot or poke out of the drainage holes, and the soil dries almost immediately.
What to do: Repot into a pot one or two sizes larger with fresh potting mix.
How to tell: Water runs straight through or sits on top, and plants stay small even with enough light.
What to do: Mix in compost and coarse material such as perlite or coco peat, or use fresh potting mix.
Start with the simplest causes (water, light and drainage). If you use any spray, choose the gentlest product that is labelled for your plant and follow its directions.
The most common causes are overwatering or poor drainage, not enough nutrients (older leaves yellow first) and too little light. Check how wet the soil is before you do anything else.
Usually not. Fix watering, light and airflow first, remove badly affected leaves and wash pests off with water. If you do spray, use the gentlest product that is labelled for your plant and follow the directions.