Plant diseases

Yellow leaves: main causes and what to do for your plant

Why a plant has yellow leaves: the six most common causes, how to tell them apart and the right fix for each.

Updated on 2026-07-14 · 7 min read

Yellow leaves are probably the most alarming — and most misinterpreted — symptom in houseplant care. It's never just one thing: it can be too much water, too little light, a normal seasonal change, a nutrient deficiency or the beginning of a more serious problem. In this guide we'll look at the six most frequent causes and how to tell them apart in seconds just by looking at the plant.

1. Overwatering (the number-one cause)

In 60-70% of yellow-leaf cases on houseplants, the cause is too much water. How to recognise it: leaves yellow all over, often starting from the bottom, and feel soft to the touch. The substrate is wet or constantly moist. If you slide the plant out of the pot, roots look dark and mushy.

What to do: stop watering immediately. Make sure the pot has drainage holes and empty the saucer. If you suspect root rot, inspect the roots and repot with fresh well-draining substrate. In general, before watering push a finger into the soil: if the top 2-3 cm is still moist, wait.

2. Underwatering (less common, but it happens)

If leaves yellow from the edges and feel dry and crisp, the problem is the opposite: the plant is dehydrated. The substrate is visibly dry and pulls away from the sides of the pot.

What to do: water generously, letting excess drain from the holes. If the substrate is so dry it repels water, immerse the pot in a container of water for 20-30 minutes so it fully rehydrates.

3. Not enough light

Plants receiving less light than they need show leaves yellowing uniformly, often those furthest from the light source. The plant becomes leggy (long thin stems, wide gaps between leaves).

What to do: move it closer to a bright window (but not into direct sun for species that can't tolerate it). Rotate the plant weekly for even growth. If natural light is scarce, consider a horticultural LED lamp.

4. Nutrient deficiency

If the plant has been in the same pot for years without repotting or feeding, the substrate is exhausted. Typical symptom: older leaves yellow uniformly while new ones stay small and pale (nitrogen deficiency), or leaves yellow between the veins while veins stay green (iron or magnesium deficiency, typical of acid-loving plants).

What to do: resume monthly feeding with a balanced liquid fertiliser in spring-summer. If the plant has been in the pot for more than 2 years, consider repotting with fresh substrate.

5. Seasonal change or normal ageing

Not every yellow leaf is a problem. It's normal for a plant to shed 1-2 lower leaves per season: those are old leaves being replaced. If only the lowest leaves yellow, in small numbers, and the rest of the plant is vigorous, there's nothing to do: remove them and let the plant work.

Transitions between spring-summer and summer-autumn can also cause minor physiological changes. Plants that just changed home (nursery arrival, moving) take 2-3 weeks to adapt and may yellow a few leaves in the meantime.

6. Drafts, cold or temperature swings

Tropical plants (calatheas, pothos, ficus, monstera) are sensitive to temperatures below 15°C and to cold drafts near windows, doors and air conditioners. Symptom: leaves yellow and drop quickly, sometimes with brown spots.

What to do: move the plant to a more sheltered spot, away from frequently opened windows and direct AC flow. Keep temperatures between 18 and 24°C.

Quick diagnosis cheat sheet

If you want a one-minute diagnosis, look at:

  • Soft leaves and wet substrate → overwatering or root rot.
  • Dry crisp leaves, dry substrate → underwatering.
  • Uniform yellowing, leggy plant → too little light.
  • Yellowing between the veins → nutrient deficiency (iron/magnesium).
  • A few lower leaves only, rest vigorous → normal ageing.
  • Rapid yellowing with drops + cold/drafts → thermal stress.

Do yellow leaves turn green again?

No. An already yellow leaf will not recover its green colour: the lost chlorophyll doesn't come back. You can remove it safely (with clean scissors, cutting at the petiole base). What matters is fixing the cause, so the new leaves that emerge are healthy. Visible recovery after correcting the problem shows up over 2-4 weeks in the new growth.