How to grow lettuce and best varieties

Lettuce is quick and easy to grow. It will do well in a container on your balcony or patio if you don't have a garden.

The Which? Gardening experts explain how to grow lettuce, plus share our Best Buy varieties.

How to grow lettuce: month by month

The best lettuce varieties from our trials

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Full testing results for lettuce

Crunchy lettuce

Lettuce for autumn sowing

Cos and romaine type lettuce

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How we test lettuce

We sowed seeds of a number of lettuce varieties indoors in May and the lettuces were planted outside in beds in the first week of June. 

We protected them with an insect-proof mesh to prevent any attack on the leaves and roots, and, as there was no rainfall during the trial, watered them as needed, to stop the soil drying out. 

All varieties were harvested when mature in early July, and then assessed, tasted and weighed, but some heads were left in the ground to see how long they would last before problems set in. The weather was very hot during the trial, and the high temperatures led to many varieties bolting (producing flowers) sooner than we would normally expect.

Growing lettuce

When to sow

Sow seed indoors from mid-February in modules or seed trays filled with a Best Buy compost for sowing seeds. Grow seedlings on in modules or small pots in a cool, well-lit place until they’re large enough to plant outside.

Alternatively, sow seeds outdoors from late March in well-prepared, loose soil in shallow, straight drills. Keep the soil moist after sowing until the seeds are growing strongly. Thin the seedlings to around 30cm apart.

If you're planning to cut the whole lettuce heads at harvest, sow at intervals of three to four weeks to keep a regular supply of lettuce going. If you're planning to just harvest the outer leaves, you don't need to sow as often - a March sowing will provide leaves from spring to summer, and an August or September sowing will provide leaves from autumn through winter.

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Planting

Plant in well-drained soil in sun or semi-shade, or into pots of a Best Buy compost for containers. Plant early sowings under a cloche or cover them with fleece to protect them to trap the sun's warmth and protect from cold winds.

Weeding

Weed regularly, especially when the plants are small.

Watering 

In dry weather, water the soil around the roots of the plants in the ground at regular intervals so the soil doesn’t dry out completely. Try to avoid wetting the leaves. Plants growing in pots will need watering more frequently; more than once a day in hot, dry weather. Touch the compost to check if it feels dry before watering.

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Lettuce in hot weather

High temperatures don’t suit lettuce, so when it gets above 25°C problems start to emerge. Bolting, when the plant starts to produce a flower spike in the centre, is the most obvious one, but the leaves will start to develop a more bitter flavour even before you spot the flower spike.

Tipburn is another common problem. It’s caused by a lack of calcium, often when the uptake of water is reduced in dry soil, and the symptoms are brown, wilting leaf edges. Leaves also blister as the skin fails to keep up with the speed of growth caused by hot weather, and heads can split if watering is irregular. 

Early sowing in March and April allows lettuce to mature before the weather gets hot, but for summer lettuce, chose varieties that grow better in warmer weather, such as ‘Thimble’, and plant them in a partly shady spot or provide them with some shade if it gets very hot. Water the soil around the roots at regular intervals to stop it getting too dry.

Growing lettuce over winter

For lettuce to harvest over winter and into the following spring, sow in August or early September. For the best crops with the sweetest flavour, grow outdoors under fleece or insect-proof mesh, such as enviromesh. We found that plants grown in a cold greenhouse produced slightly heavier crops but the flavour wasn't as good.

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How and when to harvest

Harvest in: June to October from a spring sowing, and winter and spring from an August to September sowing

Head-forming lettuces should be picked when the head feels firm. Cut the lettuce away from the roots at the base of the head.

Loose varieties can be picked as single leaves when they reach an edible size. Pick leaves from the outside and the plants will continue to grow and produce further harvests. Don't be alarmed if they start to look like palm trees with a trunk below the leaves.

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Common growing problems

Slugs and snails

Slugs and snails will eat leaves, particularly when plants are small. Pick off any that you find. Protect with organic slug pellets made from ferric phosphate, which isn’t thought to be harmful to wildlife, or water biological-control nematodes on to the soil at six-week intervals (these only kill slugs).

Read more about how to get rid of slugs and snails.

Aphids

Aphids can attack roots and leaves. Cover plants with insect-proof mesh to prevent infestation.

Read more about how to get rid of aphids.

Grey mould

Grey mould (botrytis) infects leaves in damp, humid weather. This fungal infection begins as discoloured patches on leaves and grows into fuzzy, grey patches. Remove infected parts of the plants if spotted early, or pull up the whole plant if it’s badly infected.

Tipburn

The edges of the leaves, especially those on hearting varieties of lettuce, discolour and die, making the crop very unappetising. The symptoms are less common on outer leaves, and are most common in years when temperatures are high and conditions particularly sunny and bright. Tipburn is also more likely if the soil is too dry (so uptake of nutrients is impeded) or deficient in calcium.

Unfortunately, once the damage has occurred, there's nothing much you can do. The best advice is to discard affected leaves and use what you can of the remainder.

There is no easy way to control tipburn, but keeping the soil just moist at all times, and perhaps providing some temporary shading during the hottest part of the day, will be of benefit. 

Bolting

High temperatures don’t suit lettuce, so when it gets above 25°C, problems start to emerge. Bolting, when the plant starts to produce a flower spike in the centre, is the most obvious one, but the leaves will start to develop a more bitter flavour even before you spot the flower spike.