Why are my houseplant's leaves turning yellow?

One yellow lower leaf every few weeks is normal ageing. Several yellow leaves at once with damp soil point to overwatering, so check the roots before you water again. Yellow new growth with green veins suggests a nutrient lockout, often from very hard water. Start with the watering guide.

Why does my plant drop leaves after I bring it home?

A change in light, temperature and humidity makes many plants shed a few leaves, and it usually settles within 2 to 6 weeks. Keep it in one spot, water only when the top 3 to 5 cm is dry, and do not repot or feed it during the adjustment.

How do I get rid of fungus gnats?

Let the top 5 cm of mix dry out between waterings, because the larvae need moist surface mix. Add yellow sticky traps for the adults and drench with a Bti product if the problem continues. Expect 3 to 4 weeks to break the cycle.

When is a plant beyond saving?

When the crown or the whole stem base is soft, brown and sour-smelling, the plant is usually lost. Cut healthy tip sections and root them, using the method in our cuttings guide.

Houseplant Problems & Fixes: Diagnostic Guide

Houseplant Problems & Fixes: A Visual Diagnostic Guide

Quick answers

Why are my houseplant's leaves turning yellow?: One yellow lower leaf every few weeks is normal ageing. Several yellow leaves at once with damp soil point to overwatering, so check the roots before you water again. Yellow new growth with green veins suggests a nutrient lockout, often from very hard water. Start with the watering guide.
Why does my plant drop leaves after I bring it home?: A change in light, temperature and humidity makes many plants shed a few leaves, and it usually settles within 2 to 6 weeks. Keep it in one spot, water only when the top 3 to 5 cm is dry, and do not repot or feed it during the adjustment.
How do I get rid of fungus gnats?: Let the top 5 cm of mix dry out between waterings, because the larvae need moist surface mix. Add yellow sticky traps for the adults and drench with a Bti product if the problem continues. Expect 3 to 4 weeks to break the cycle.
When is a plant beyond saving?: When the crown or the whole stem base is soft, brown and sour-smelling, the plant is usually lost. Cut healthy tip sections and root them, using the method in our cuttings guide.

Key takeaways

Check soil moisture and light before you look for pests or disease
Note which leaves are affected: old, new, tips or whole plant
Repeat every pest treatment weekly for at least 3 weeks
Never fertilise a plant that is already struggling

Table of contents10 sections

Houseplant problems at a glance
Diagnose houseplant problems in this order
Reading the houseplant leaf pattern
Sudden houseplant leaf drop
Is it a light problem?
Houseplant pest identification and treatment
Rescuing a houseplant with root rot
Why houseplant problems start and how you fix them
Common mistakes
Next steps

Houseplant problems and fixes in this visual diagnostic guide match each leaf symptom to its cause, from overwatering to pests.

Most houseplant problems come from water, light or humidity, in that order, and pests usually show up on plants already stressed by one of the three. The fastest diagnosis is a fixed routine: check the soil, check the light, then read the pattern on the leaves. This guide gives that routine, a symptom table, a pest chart with treatment timings and a rescue method for rotting roots.

It sits in the Indoor Plants guides alongside How to Water Houseplants Correctly, Humidity for Houseplants and Repotting Houseplants Without Stress, which cover the underlying care in more depth.

Houseplant problems at a glance

Question	Answer
Normal leaf loss	One older leaf yellowing and dropping every few weeks is ageing, not a fault
Settling-in period	2 to 6 weeks of leaf drop after a move or purchase is common
Cold damage	Many tropical plants suffer below about 10°C (50°F); some, like Ficus, object to sudden drafts well above that
Healthy roots	Pale cream or white, firm, with little smell
Rotten roots	Brown or black, mushy, sour or swampy smell
Pest treatment rhythm	Every 5 to 7 days for at least 3 weeks
Quarantine	Keep an infested plant apart until it has been clean for 3 weeks

Diagnose houseplant problems in this order

Changing several things at once makes it impossible to know what worked. Run through these steps before you act.

Test the soil. Push a finger 3 to 5 cm down and lift the pot. Dry and light, damp, or wet and heavy? Wet soil on a wilting plant means roots are failing, not thirsty.
Check drainage. Look for holes, a full saucer or a decorative pot with water pooled in the base.
Measure the light. Note the distance to the nearest window and which way it faces (see the light table below).
Inspect both sides of the leaves. Use a phone camera zoom or a hand lens, and look along stems and in leaf joints for webbing, fluff, bumps or sticky residue.
List recent changes. A new position, repotting, heating coming on, a holiday, a new fertiliser or a cold night by the glass can all explain a problem that appears 1 to 3 weeks later.

Reading the houseplant leaf pattern

Where the damage appears matters as much as what it looks like. Old leaves yellowing points to water, nutrients or ageing. New growth that’s pale, small or distorted points to light, nutrient lockout, pests or a root problem. Damage only on the tips and edges is nearly always about water quality, dry air or irregular watering.

Symptom	Likely cause	Fix
Lower leaves yellow and soft, soil wet	Overwatering, poor drainage	Stop watering, empty the saucer, check the roots, let the top 3 to 5 cm dry
Crisp brown tips, green leaf otherwise	Dry air, mineral build-up, irregular watering	Flush the pot with plenty of water, water evenly, see humidity guide
Brown tips with a yellow halo	Salt or fertiliser build-up	Flush with 3 to 4 times the pot volume of water, pause feeding for a month
New leaves yellow, veins stay green	Iron or manganese lockout, often high pH from hard water	Switch to rainwater or filtered water, use a balanced feed with micronutrients
Drooping, soil dry, recovers after watering	Underwatering	Soak from below for 20 to 30 minutes, then drain
Drooping, soil wet	Root rot	Unpot and inspect the roots (rescue steps below)
Long gaps between leaves, pale, leaning	Too little light	Move within 1 m of a bright window or add a grow light
Bleached or papery patches on the sunny side	Sunburn through glass	Pull back from the window or filter with a sheer curtain
Dark, water-soaked patches after a cold night	Chill damage	Move away from the glass and cold drafts; the damaged leaves will not recover
Brown spots with yellow rims	Fungal or bacterial leaf spot	Remove affected leaves, water the soil only, improve airflow
Corky blisters on undersides of leaves	Edema from wet soil with low light and cool air	Water less; the cause is a water imbalance, not a pest
Roots circling or pushing out of the drainage hole	Rootbound	Repot one size up in spring

Sudden houseplant leaf drop

Leaf drop that begins within days of a change is a stress response. Ficus species such as the weeping fig and fiddle-leaf fig are well known for it, but calathea and many foliage plants do the same. Look at the timing before the plant itself.

Within 1 to 3 weeks of buying: normal adjustment to a new light level. Hold steady rather than repotting.
After the heating switches on: dry air and warm drafts from radiators. Move the plant at least 1 m from the heat source.
After a cold night: leaves touching a window can drop within days. Pull plants 10 to 15 cm back from glass in winter.
Green leaves dropping with a dry root ball: long drought. Soak from below.
Green leaves dropping with soggy soil: roots are suffocating. Unpot and check.

Is it a light problem?

People over-estimate indoor light. A bright room can still be dim for a plant a few metres from the glass, because light falls off steeply with distance. Use these as rough guides, and remember that a phone light-meter app is only an estimate.

Level	Approximate lux	Typical position	Plants that cope
Low	Under 2,500 (about 250 foot-candles)	North window, or 3 m or more from any window	Snake plant, ZZ plant, cast iron plant
Medium	2,500 to 10,000	East window, or 1 to 2 m from a south window	Philodendron, pothos, peace lily
Bright	10,000 and above	Right at a south or west window	Succulents, citrus, croton, ficus

A quick test: at midday, hold your hand 30 cm above the plant. A sharp-edged shadow means bright light; a soft blurred one means medium; barely visible means low. For low-light spots, choose from 15 Best Low-Light Houseplants rather than expecting a sun lover to adapt.

Houseplant pest identification and treatment

Look for pests whenever new growth is distorted, leaves feel sticky or you see anything moving. Most indoor infestations arrive on a new plant, so inspect purchases before they join your collection.

Pest	What you see	Treatment
Spider mites	Fine stippling, webbing in leaf joints, worst in dry warm rooms	Rinse the whole plant in a shower, wipe leaf undersides, repeat every 5 to 7 days for 3 weeks; raise humidity
Mealybugs	White cottony tufts in leaf joints and on stems	Dab each one with a cotton bud dipped in 70% isopropyl alcohol; repeat weekly
Scale	Brown or tan domed bumps on stems and midribs that scrape off with a fingernail	Scrape or dab with alcohol; use horticultural oil for heavy infestations
Thrips	Silvery streaks, tiny black specks, flecked flowers	Blue sticky traps; spray insecticidal soap every 5 to 7 days
Fungus gnats	Small dark flies around the pot; larvae live in the top 5 cm of damp mix	Let the surface dry, yellow sticky traps, Bti drench for persistent cases
Aphids	Green, black or brown clusters on soft new growth, sticky honeydew	Wipe off, or spray with soapy water and repeat

Spider mite eggs hatch within a few days in warm rooms and mature in roughly one to two weeks, so a single treatment always leaves survivors. That is the reason for the three-week repeat rule. Sprays and wipes only reach what they touch, so treat leaf undersides and stem joints deliberately. For home-made sprays, see 7 Natural Remedies Every Gardener Should Know How to Make.

Test any alcohol, soap or oil treatment on one leaf and wait 24 hours before treating the whole plant, because thin or waxy leaves can scorch. Keep sprays away from pets and children until dry, read product labels, and never mix products.

Rescuing a houseplant with root rot

Root rot is the most common reason a plant dies despite regular care. Act when the plant wilts in wet soil, the base of the stem darkens or the mix smells sour.

Unpot and rinse. Wash the roots gently under lukewarm water so you can see them.
Sort the roots. Keep firm, pale roots. Remove brown, mushy or stringy ones with scissors wiped in alcohol between cuts.
Judge the damage. If more than about two thirds of the roots are gone or the crown is soft, switch to taking cuttings instead.
Reduce the top. Remove a share of the foliage that roughly matches the roots you removed, so the remaining roots aren’t asked to supply too many leaves.
Repot in fresh mix. Use a clean pot with drainage holes, of equal or slightly smaller size, and a free-draining mix (see repotting guide).
Water once, lightly, then wait. Keep the plant in bright indirect light and don’t feed it for at least 6 to 8 weeks.

Keep a note of the date you water each troubled plant. A quick check of those dates against symptoms often reveals the pattern faster than any chart.

Why houseplant problems start and how you fix them

Overwatering causes root rot and invites fungus gnat larvae, so letting the top few centimetres of potting mix dry prevents both. Low humidity browns fern and calathea leaves, and a hygrometer, a pebble tray or grouping plants improves the air. Spider mite thrives in dry heat and spreads webbing, while a rinse and neem or soap spray controls light infestations.

Mealybug and scale hide in leaf joints and suck sap, and rubbing alcohol on a cotton bud kills them. Yellow lower leaves mean the plant needs less water or more nitrogen, and you’ll find the soil tells you which. Sun scorch bleaches succulent and orchid leaves, so a sheer curtain shades them. Why do leaves drop after a move? Light and temperature changes stress plants, and a stable spot reduces the shock. Your plant retailer or extension service can identify stubborn pests.

Common mistakes

Treating every droop with water. A drooping plant in wet soil has failing roots, and more water speeds up the damage. Test the soil first.
Feeding a sick plant. Fertiliser pushes growth that damaged roots can’t support and adds salts. Wait until new growth appears.
Jumping to a larger pot. Extra mix stays wet for weeks and invites rot. Go up by 2 to 5 cm in diameter only.
Using mist to treat dry tips. Misting raises humidity for minutes, and the tip burn is usually caused by water quality or irregular watering. Fix the root cause.
Stopping pest treatment after one spray. Eggs survive and hatch. Repeat weekly for three weeks.
Ignoring the undersides of leaves. Mites, scale and thrips all start there.
Cutting off every brown tip. Trim only the dead tissue and leave a thin brown edge, otherwise the cut edge browns again.

If a pet has chewed a plant, see Pet-Safe Houseplants.

Next steps

Start with How to Water Houseplants Correctly, because watering explains most of what you have just read. Then compare your room against 15 Best Low-Light Houseplants, and learn to spot early warning signs in Reading Plant Signals. Back to the Indoor Plants guides.

Frequently asked questions

What causes sticky leaves on a houseplant?

Sticky residue is usually honeydew from sap-sucking pests such as aphids, mealybugs or scale. Check stems, leaf joints and undersides for clusters, white fluff or brown bumps. Wipe the leaves, treat the pest and repeat weekly for three weeks, since eggs survive a single treatment.

How do I get rid of spider mites on houseplants?

Rinse the whole plant in a shower, wipe the leaf undersides and repeat every 5 to 7 days for three weeks. Raise humidity, since mites thrive in warm, dry rooms. Test any soap or oil spray on one leaf first and follow the product label.

What are the white fluffy spots on my plant?

They are most likely mealybugs, sap-feeding insects that hide in leaf joints and along stems. Dab each one with a cotton bud dipped in 70% isopropyl alcohol and repeat weekly. Test one leaf first, because thin leaves can scorch.

Why are the edges of my plant's leaves brown and crispy?

Crisp brown edges usually point to dry air, mineral build-up or irregular watering. Flush the pot with plenty of water, water evenly and check the humidity. Trim only the dead tissue and leave a thin brown rim, since a deep cut browns again.

Can a houseplant recover from root rot?

Yes, if enough firm, pale roots remain. Unpot, rinse the roots, cut off brown or mushy ones with clean scissors and repot in fresh mix in a pot with drainage holes. If more than about two thirds of the roots are gone or the crown is soft, take cuttings instead.

Why do my plant's leaves have brown spots with yellow rims?

That pattern often means fungal or bacterial leaf spot. Remove affected leaves, water the soil and not the foliage, and improve airflow around the plant. Cold, wet conditions encourage spread, so check light and watering at the same time. Isolate the plant if spots keep spreading.

Is it safe to spray pesticide on houseplants indoors?

Use only products labelled for indoor plants, follow the label exactly and never mix products. Keep sprays away from pets and children until leaves are dry, and ventilate the room. Start with milder options such as wiping, rinsing or insecticidal soap, and test on one leaf first.

What does a houseplant look like when it has too little light?

It grows pale, small leaves on long, leaning stems with big gaps between them, and growth slows or stalls. Variegated leaves turn plain green. Move the plant within 1 m of a bright window or add a grow light, and water less.

Why does my plant have papery brown patches on one side?

That is probably sunburn through glass, on the side facing the window. Strong afternoon sun scorches leaves, especially on plants used to shade. Pull the plant back from the glass or filter the light with a sheer curtain. Scorched tissue will not recover.

How long should I treat a houseplant pest before it is gone?

Treat every 5 to 7 days for at least three weeks, and keep the plant apart until it has stayed clean for about three weeks. Eggs hatch between treatments, so a single spray never finishes the job. Check leaf undersides and stem joints each time.