Birthday
HydrangeasA houseplant cannot complain, but it nearly always sends a signal: its leaves change colour or drop, or it stops flowering. The good news is that most problems are not mysterious diseases but growing conditions — light, watering, air and the pot. Here are 10 common symptoms and their likely causes.
Healthy plants delivered: potted houseplants.
How to read the symptoms
The same sign can have several causes, so look at the whole picture: when the symptom appeared, what changed in your routine, and what the roots and soil look like. Start with the simplest factors — light and water.
Leaf problems
- Brown, dry tips. Usually dry air from radiators, uneven watering or salts building up from hard water and fertiliser. Use water that has stood for a day and flush the soil with a generous watering every few months.
- Pale or brown scorch marks. These appear when a plant moves suddenly from shade into direct sun. Acclimatise it gradually.
- Yellow or brown spots. These can signal fungal or bacterial leaf spot. On African violets, pale marks are often left by cold water on the leaves.
- Dropping leaves. A typical stress response to draughts, temperature swings or being moved. Ficus plants are especially sensitive to a change of place.
Growth and flowering
- Plenty of leaves, few flowers. Too much nitrogen or too little light. Flowering needs good light and a feed richer in phosphorus and potassium.
- Small new leaves and wilting. Lack of light or nutrients, or a pot so tight that roots fill it completely.
- A long, pale stem. The plant is stretching for light: move it closer to a window or add a grow light.
Roots, coatings and distortion
- Soft brown or black roots. A sign of root rot from overwatering and poor drainage. Lift the plant, cut away affected roots, repot into fresh, well-drained mix and water less often.
- White powdery coating. Powdery mildew is a fungal disease. Remove affected leaves, move the plant away from others and treat with a fungicide as directed.
- Curled, distorted leaves. Often the work of sap-sucking pests such as aphids or thrips.
Pests
Spider mites like warm, dry air and leave fine webbing and pale speckles on leaves. Mealybugs look like tufts of cotton wool in leaf joints, scale insects like brown bumps on stems, and thrips leave silvery streaks. Isolate an infested plant at once, rinse it under a lukewarm shower and treat it with a suitable insecticide exactly as directed, repeating until no new pests appear.
What to do first
- Move the plant away from others if you suspect pests or disease.
- Check soil moisture 2–3 cm down and inspect the roots.
- Assess the light: is the plant too far from a window or in harsh direct sun?
- Do not feed a sick plant — fertiliser is not a cure and can harm damaged roots.
We have collected the most common care mistakes in 10 ways to kill a houseplant, covered diseases of indoor roses separately, and explained gentle feeding in natural fertilisers for houseplants.
FAQ
Why are the lower leaves turning yellow?
If one or two old lower leaves yellow, that is natural renewal. If many leaves yellow at once, check watering and the roots.
Should I mist plants to fight dry air?
Misting raises humidity only briefly. A humidifier or a tray of wet pebbles is more reliable.
Can a plant with rotten roots be saved?
Often, yes, if some healthy pale roots remain: keep those, cut away the rest and repot into fresh mix.
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Author: Maria Svitlovir
Graduated from Taras Shevchenko National University of Kyiv, Institute of Biology and Medicine (2001). BSc in Biology, MSc in Horticulture. Writes about plants, works at a garden centre selecting and repotting plants, and contributes to plant reference guides.
