Lettuce - Lactuca sativa

Lettuce Lactuca sativa can be harvested 4 weeks after sowing. Sow mid-June in a shady spot into open soil (as they dislike being transplanted) and then every couple of weeks to keep a constant supply. There are more than 100 species of lactuca. Choose a bolt resistant variety. Keep well watered, else they tend to get bitter. Sleepwort is the common name for wild lettuce.

Any thinnings can be added to salads.

• Cos lettuce is also known as Romaine.
• Cos and 'Webbs Wonderful' are old-fashioned varieties which are crunchy and have a slightly bitter taste. Pick the whole head when they are ready. 'Webbs Wonderful' has a sweet taste and slow to bolt.
• Butterhead lettuce have tender leaves, which will quickly wilt if not put into water.
• Iceberg types take longer to grow and need more water, but are sweet, crunchy and juicy.

Lettuce are divided into two main groups, hearting lettuces - those with a dense centre and the loose leaf type. Hearting lettuce tend to lack flavour but add crunch to a salad.

With cut-and-come again varieties as their name suggests, you pick off the outer leaves that you need for your salad, and leave the plant to continue growing, this keeps the plant young and tender. Therefore you should only need a couple of sowings to have salad leaves all through the summer and into autumn. They are also ideal for growing in pots and tubs if you have restricted space.

Growing lettuce

Lettuce need to be grown quickly to avoid the leaves becoming bitter. Sow seeds thinly, outside in drills, half inch deep from mid-spring to late summer. Sow on a cloudy day, or late in the day if it's sunny, giving the seeds a cooler climate to germinate. Thin out initially when the seedlings are touching, transplanting the thinnings to where you have gaps, alternatively they can be eaten.

Pests & diseases

Slugs and snails are likely to be the biggest problem. Whilst specific nematodes are available and slug pubs or pellets can be used, removing their hiding places by gathering leaves and debris in the winter and spring and putting bird feeders out will also encourage birds into the garden and they will also snack on any stray slugs.

Cutworms and chafer grubs can cause young seedlings to wilt for no apparent reason, older plants wilting is likely to be lettuce root aphid, pull these up and burn the plants, else put them in the bin. If the summer is cold and wet they may suffer from grey mould or botrytis, this is generally caused by the plants being too close together, removed any affected plants.

Culinary use:

Lettuce are high in fibre and a source of vitamin K.

Cultivars and varieties: