Post category: Lettuce
Lettuce has a long history of cultivation going back, it is thought, to at least ancient Egyptian times. The cultivated lettuce varieties were derived from a wild lettuce species that grows across continental Europe and the Middle East. Resembling the wild sow thistle weed of gardens, the wild lettuce was apparently very bitter and had to be blanched prior to eating, much as seakale still is. Centuries of breeding changed the lettuce, making it more palatable and more leafy.
The wide range of varieties includes five kinds: ordinary butterhead types, looseleaf types, iceberg or crisp varieties from North America, cos lettuce from eastern Europe and Chinese stem lettuce. In addition there are many variations on these types – red kinds, frilly edged kinds, oak-leaved kinds. Each sort has its own merits and each kind appeals to different palettes.
The butterhead and looseleaf kinds are easiest to grow, the crisp and cos kinds slower to develop and needing better conditions. Butterhead kinds can be grown all year round, the winter crops with the protection of a cloche or greenhouse. Only very keen growers will attempt year-round production but most people could easily produce a couple of summer crops.
The nutritional value of lettuce varies with the variety: looseleaf and cos types have about double the value of iceberg. It has small amounts of dietary fibre, some carbohydrates, a little protein and a trace of fat. Its most important nutrients are vitamin A – the greener, the better – and potassium and a moderately good source of vitamin C, calcium, iron and copper, and it is 95% water. Lettuce is mostly eaten fresh in salads and sandwiches but it can feature in cooked dishes too.
Site and soil
Lettuce is a quick-growing, soft crop that needs good growing conditions at all times. The site should be open to full sunshine, not shaded. Some shelter is useful though because temperature levels will be higher and this is an advantage early and late in the year. The soil needs to be rich, well drained with plenty of humus.
There are dozens, scores, of lettuce varieties. Some standards include: ‘Webb’s Wonderful'(crisphead), ‘All The Year Round’ (butterhead), ‘Salad Bowl’ (looseleaf), ‘Celtuce’ (chinese lettuce), ‘Lobjoit’s Green’ (cos).
Lettuce can be sown almost year-round, choosing suitable varieties for the season. The fancier kinds, cos and iceberg kinds are effectively restricted to summer growing because they need warm weather and bright light.
Lettuce is normally used as ‘hearted’ lettuces, cut just above soil level, but it can be used from the garden at any time, especially the looseleaf types that can have leaves picked off without cutting the stem. Even thinnings can be used.
Lettuce mainly suffers form greenfly infestation and this need to be watched. Wilting, early bolting and scorching at the edges of the leaves are caused by unsuitable growing conditions, mainly too hot or dry. Grey mould can cause damage in cool, damp conditions.