Lettuce (lactuca sativa)

Why plant

It's easy to grow and available all year round. Just plant little and often for steady supply of young leaves. There are many different varieties, much tastier than from a supermarket

Interesting uses

The ancient relative of the modern day lettuce contains a narcotic similar to opium. Dried lettuce juice was used to aid sleep in Elizabethan times and through World War II lactucarium, a sedative made from wild lettuce extracts, was used in hospitals.

Origins

The earliest mention of lettuce is in Ancient Egypt where it was considered an aphrodisiac. The Romans cultivated the plant, using it's narcotic properties by taking it at the end of a meal to induce sleep, and brought it to Britain.

Health benefits

All varieties of lettuce are low in calories, but those with darker leaves have more nutritional value. So iceberg lettuce contains little nutrition, whereas romaine is more beneficial.

Beta-carotene is the main beneficial nutrient found in the darker-colored greens. it's an antioxidant and can give some protection against some cancers and heart disease. Another element, folic acid, is beneficial in the beginning stages of pregnancy as well as possibly also contributing to the prevention of heart disease and inflammation. Lettuce are an important source of vitamin C, potassium and fibre.

The plant is a rich source of vitamin K, potentially able to increase bone mass and possibly beneficial for Alzheimer patients by limiting neuronal damage in the brain.

Varieties

  • Butterhead: forms a loose head of leaves with a buttery texture. Popular types are boston, bibb, buttercrunch and tom thumb.
  • Crisphead or Iceberg: has a tight, dense head. Valued more for it's crunchy texture since the taste is mild.
  • Looseleaf: includes some of the most attractive leaves. Tender, delicate and mild favoured, popular types are oak leaf and red leaf.
  • Romaine or Cos: has long, sturdy leaves.

Planting

Plant a few seeds every couple of weeks for a continuous supply. Make rows 1/2in (13mm) deep and 12in (30cm) apart. Water the bottom of the row and sow the seeds thinly.

You can sow indoors as early as February in seed trays and pant out early March under a cloche. Sow outdoors from March right through to October depending on the variety. In later months a greenhouse or cloche will be required.

Some varieties may not germinate in mid Summer if soil temperatures are too high. To combat this provide some shade.

Aftercare

As the first true leaves appear thin the seedlings to be 12in (30cm) apart. Water if dry. You may need to provide some protection, such as with chicken wire, where birds are a problem.

Harvesting

When the lettuce has formed a firm heart cut away at ground level.

Recipes

Chicken caesar salad

Creamy chilled basil, pea and lettuce soup

Lettuce rolls

Little gem lettuce and parmesan risotto

Quick braised lettuce and peas

Common problems

Slugs and snails: Will decimate young seedlings overnight. Use beer traps, sawdust, eggshell barriers or copper tape. Most effective is to gather slugs and snails up late evening, especially if the ground is moist after rain, and remove to some distance away. After a week of doing this you'll have few problems, though this has to be repeated periodically to catch maturing young ones. Slug pellets are not advisable since they can harm other wildlife, pets and young children if eaten in quantity.

Lettuce root aphid: This will cause maturing plants to suddenly wilt and die back, usually in Summer. The aphids are hard to spot since they attack the roots, but if there are lots of ants around the plants this might be a sign since the ants feed on honeydew the aphids produce. Keep the lettuce well-watered since the problem can be worse when conditions are dry. Pull up any affected plants and destroy them. Some lettuce varieties are resistant to root aphid.

Grey mould: This problem arises in cold, damp summers when a fuzzy grey mould grows on leaves. At the first sign remove the infected material and destroy. Plant your lettuces at the appropriate distance apart since overcrowding may be the cause.

 

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