Growing Lettuce

Lettuce can be grown in any home garden. It is a cool-weather crop, being as sensitive to heat as any vegetable grown. It is by far the most widely used salad crop in North America, and is also important in Australia and most countries in Europe and South America.

Lettuce has been cultivated for ages, possibly longer than any other common vegetable crop. Pictures of a pointed-leaved lettuce have been found in Egyptian tombs dating back to 4500 B.C.

Lettuce has been grown not only as a food but as a medicinal herb. Its milky juice is recommended in The Herbal as a sedative. In Germany, Lactuca vurisa, a close lettuce relative, was used to induce sleep.

Garden lettuce has been cultivated so long that its origin is uncertain. So far, it has not been found in the wild. Plant geographers and historians hold that its precursors originated in the Mediterranean area, possibly Egypt, and that its seeds were carried throughout the world by travelers, explorers and conquerors.

In Canada, lettuce culture is partially limited to spring and autumn. In some favored locations, such as areas of high altitude or in far-northern latitudes, lettuce grows to perfection in summer. Planting in the wrong season is responsible for most of the failures with this crop.

Any rich soil is adapted to lettuce, although the plant is sensitive to acid soil. A commercial fertilizer with a heavy proportion of phosphorous is recommended. It is a shallow-rooted crop that needs both good drainage and a steady supply of water. Abundant organic matter blended into garden soil helps provide these needs. Because of the shallow root system, deep cultivation should be avoided.

Start spring lettuce indoors or in a hotbed and transplant it to the garden when the plants have four or five leaves. Gardeners need not wait for the end of light frosts, as lettuce is not usually harmed by a temperature as low as 28F (-3 C), if the plants have been properly hardened.

By starting a new crop of lettuce every two or three weeks, one will always, in successive crops, have the making of a fresh, bright, crisp addition to any meal. Generally, the first crisphead and butterhead plants are started indoors four to six weeks and loosehead types two to three weeks, before the last average frost.

Allow about 6 weeks for growing the plants. For the fall crop, the seed may be sown directly in the row and thinned; there is no gain in transplanting.

For hand culture, plant about 14 to 16 in. (35 to 40 cm) apart each way. Where gardeners grow leaf lettuce or desire merely the leaves and now well-developed heads, the spacing in the rows may be much closer. In any case it is usually best to cut the entire plant instead of removing the leaves.

All lettuce types should be harvested when full size but young and tender. Over-mature lettuce is bitter and woody. Leaf lettuce is harvested by removing individual outer leaves so that the center leaves can continue to grow.

Butterhead or romaine types can be harvested by removing the outer leaves, digging up the whole plant or cutting the plant about an inch above the soil surface. A second harvest is often possible this way. Crisphead lettuce is picked when the center is firm.

There are many excellent varieties of lettuce, all of which do well in the garden when conditions are right. Where warm weather comes early, it is seldom worthwhile to sow head lettuce seed in the open ground in the spring with the expectation of obtaining firm heads.