A generation ago, few gardeners grew lettuce. Iceberg lettuce was all the rage, and while it keeps forever in the fridge and ships beautifully, it is a humdinger to grow at home. These finicky plants take up to ninety-five days to mature, and they tend to bolt, or turn to seed, when temperatures rise above 70 degrees F – a challenging situation for almost any gardener.
Today, though, leaf and Romaine lettuces have made a big comeback. They are lauded for their lovely colors and textures; they also have more nutrition and flavor than most crisp head types. Best of all, they’re a cinch to grow in the backyard garden. They mature quickly, tolerate light frosts, and bear more heat before bolting. If you’ve never grown lettuce before, try these versatile, appealing crops.
Lettuces need a rich, humus soil. This is one of the few situations in which too much nitrogen won’t hurt your harvest. Dig four inches of composted manure into the soil and till it to a depth of at least eight inches. Lettuce grows best with a soil pH between 6.0 and 7.0, so add lime if your soil is acidic. Choose a sunny location for best growth, although lettuce can tolerate some shade, especially in hot climates. If you’re short on space, tuck lettuce into containers or grow it amidst other vegetables or even perennial and annual flowers. Lettuce is a pretty enough plant to mingle with the ornamentals.
Fertilize lettuce plants mid-season with an all-purpose fertilizer, a dose of fish emulsion, or even a shovelful of rotted manure. In addition to plenty of nitrogen, the other most essential ingredient to for successful lettuce growing is moisture. Lettuce plants have shallow roots that dry out quickly. In dry conditions, the plants become bitter and bolt more quickly. Water frequently to keep the soil evenly moist, and try to avoid alternate periods of drought followed by heavy water. Mulch lettuce with untreated grass clippings at a rate of one inch per week. Heavier applications won’t decompose and will become a slimy mess.
To plant lettuce, sow seeds directly in the ground as soon as it can be worked. Lettuce germinates best in cool conditions when soil temperatures are around seventy degrees. Sow the seeds ¼ inch deep and keep the soil moist. Sow another crop mid-summer, followed by one in late summer, six weeks before the last expected frost. With this approach, you can have salad throughout the summer.
Space the lettuce seeds one inch apart in rows eight inches apart. Thin lettuce plants to eight inches apart once they have sprouted.
If you prefer, start lettuce seeds indoors six weeks before the last expected frost. Lettuce seeds need light to germinate, so plant them shallowly and keep the soil moist.
To harvest leaf lettuce, cut plants when they stand six inches high with a sharp knife or kitchen scissors. Another option is to remove the outer leaves, leaving the younger leaves intact. With this approach, the plants continue growing and you can harvest them two or three times.
As temperatures rise, you can extend the growing season by placing a shade or even a piece of cheesecloth over the lettuce crop. When the plants become bitter, though, there’s nothing left to do but toss them in the compost heap or feed them to the pigs.
When choosing lettuce varieties, consider your climate and growing conditions. In hot climates, select slow-bolting varieties. Try a frost-tolerant type, such as in cold climates or for fall gardening. Although lettuce doesn’t suffer from many disease or pest problems, West Coast gardeners may encounter mosaic virus. When shopping for seeds, look for varieties that are resistant to this disease.