Why Tomato Leaves Turn Yellow (and How to Fix It)

Tomato leaves turning yellow is a common concern for gardeners, especially during the growing season. In many cases, yellow leaves are a normal part of plant growth, but they can also be a sign that something needs attention.

The key is to look at which leaves are turning yellow and how the plant is growing overall.

Most causes are easy to fix once identified.

Older leaves turning yellow

If the lower leaves of a tomato plant turn yellow while the rest of the plant looks healthy, this is usually normal.

As tomato plants grow, older leaves naturally die back so the plant can focus energy on new growth.

You can remove these leaves if they look untidy.

Overwatering

Too much water can cause tomato leaves to turn pale or yellow.

When soil stays waterlogged, roots struggle to absorb nutrients.

Signs of overwatering include:

• yellow leaves

• slow growth

• soggy soil

Let soil dry slightly between watering.

If you’re unsure, see how often to water a vegetable garden.

Underwatering

Dry soil can also cause leaves to yellow and wilt.

Tomatoes need consistent moisture, especially in containers and during warm weather.

Water deeply so moisture reaches the roots.

Irregular watering can stress plants.

Nutrient deficiency

Tomatoes are fast-growing plants and need nutrients throughout the season.

Yellow leaves may appear if soil lacks nutrients.

Adding compost or feeding plants regularly can help.

Container-grown tomatoes especially benefit from feeding once flowers appear.

You can read more in best soil for vegetable gardening in the UK.

Cold weather stress

Tomatoes prefer warm conditions.

If temperatures drop, plants may show yellowing leaves or slow growth.

This usually improves once weather becomes warmer.

Natural leaf loss

As tomato plants grow larger, it’s normal for some leaves to yellow and fall off.

As long as:

• new growth looks healthy

• flowers and fruit are developing

there’s usually no problem.

When to worry

You may need to investigate further if:

• many leaves turn yellow quickly

• growth stops

• leaves develop spots

• the plant looks weak

Most tomato problems improve with steady watering and warm weather.

For growing advice, see how to grow tomatoes in the UK.

Tomato plants are resilient

Tomatoes often recover quickly once watering, feeding, or temperature issues are corrected.

Yellow leaves don’t always mean something is wrong — they’re often part of normal growth.

With consistent care, tomato plants usually continue growing and producing fruit.