Why Lettuce Tastes Bitter (and How to Prevent It)

Lettuce is usually easy to grow, but sometimes it develops a bitter taste. This often happens when plants grow in stressful conditions, especially during warm weather.

Bitterness is a natural response that helps the plant cope with heat and dry soil.

The good news is that a few simple growing habits can help keep lettuce mild and tender.

Hot weather

Lettuce grows best in cooler temperatures.

During warm weather, lettuce can become bitter and begin to bolt (produce flowers).

Growing lettuce in:

• spring

• early summer

• late summer

often produces the best flavour.

Providing some shade during hot weather can help.

Dry soil

Dry soil is one of the most common causes of bitter lettuce.

Lettuce needs consistent moisture because it grows quickly and has shallow roots.

Keep soil:

• moist

• not waterlogged

You can read more in how often to water a vegetable garden.

Lettuce growing too slowly

When lettuce struggles to grow, flavour can become stronger and more bitter.

Healthy soil and steady watering help plants grow quickly and stay tender.

Adding compost before planting improves growth.

See best soil for vegetable gardening in the UK for more advice.

Harvesting too late

Lettuce often tastes best when harvested young.

If leaves grow large or plants begin flowering, bitterness increases.

Harvesting regularly helps keep plants producing fresh leaves.

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

Choosing the right growing conditions

Lettuce usually tastes best when grown:

• in mild temperatures

• with steady watering

• in soil with compost added

• with regular harvesting

Small, regular sowings often produce better results than growing large batches.

Bitter lettuce is still usable

Even when lettuce tastes slightly bitter, it can still be eaten.

Mixing it with other salad leaves often improves flavour.

Growing lettuce in cooler conditions usually produces the best taste.