Why vegetable leaves turn yellow

First check: feel the soil or potting compost below the surface and compare older leaves with the newest growth. Yellowing describes a symptom; it does not identify a single deficiency.

Read the pattern before feeding

A few ageing lower leaves are less concerning than yellowing that spreads through a plant. Note when it started and whether neighbouring plants show the same change. A whole bed changing after heavy rain points you towards growing conditions; one affected plant deserves closer inspection.

General paling that starts on older leaves, together with weak growth, can suggest nitrogen shortage. Yellow tissue between greener veins can suggest a different nutrient problem. These patterns overlap with other causes, so use them to guide checks rather than choose a product immediately.

Check water and roots

Drought and prolonged saturation can both cause yellowing. In very dry soil, nutrients may be present but unavailable to the plant. Waterlogged roots lack oxygen and may decay. Cold conditions, poor establishment and compacted soil can also interrupt growth.

If roots are dry, water slowly and check that moisture reaches the root ball. If compost remains sodden, check drainage holes and stop adding water until it needs it. Avoid digging or walking on saturated beds.

When feeding makes sense

A container crop growing in old compost may have exhausted its nutrient supply. Once watering and drainage are appropriate, use an organic feed suited to that crop at the label rate. Extra feed cannot repair oxygen-starved roots.

For recurring problems in beds, test the soil before adding more nutrients. Soil pH affects availability: a nutrient can be present without being accessible. Do not add lime, wood ash or Epsom salts simply because leaves look pale.

Look for other clues

Inspect leaf undersides and stems for insects, webbing, spots, rot or distorted growth. Mottling combined with distortion needs crop-specific investigation; it is not proof of hunger. Photograph symptoms before removing damaged material.

Watch the new growth after correcting an identified cause. Older leaves may stay yellow. Record the date and action so you can see whether the problem is still progressing.

Back to Solve a Growing Problem · Find your crop guide

Further reading: RHS guidance on chlorosis and nutrient deficiencies.

By Simon Adams · Published 27 October 2026. Adapt advice to your crop and conditions.