Lettuce growing goes back at least to the Greeks and Persians in 500 B.C. Columbus first brought lettuce seed to the Americas. There are many different kinds of lettuce, all Lactuca sativa. But they can be sorted into 5 basic types: butterhead, celtuce, crisphead, looseleaf, and romaine.
Those are my 2 favorites in salads and, in my experience, the easiest to grow. Boston and Bibb lettuce are butterhead types, as is any lettuce described in a seed catalog as making a “loose head.” The butterhead lettuces are green-leafed and healthy, have a wonderful garden-fresh flavor, and are ready to harvest only a little later than leaf lettuce.
But butterheads, like crispheads, can’t stand hot weather. You will have more wonderful lettuce than you can eat for a brief period. Then, when the weather turns hot, that’s the end of it.
Crisphead.The most familiar crisphead is iceberg lettuce, the kind with the big, firm head that you buy in stores and eat in restaurants. Years ago it dominated the commercial lettuce market to the exclusion of all other salad greens, despite the fact that it has less color and taste and fewer vitamins and minerals than any other kind of lettuce. (It does store and transport well, though.)
But crisphead lettuce is the hardest to grow in your home garden and is really the least desirable. And it takes twice as long to mature as leaf lettuce. The inside leaves of a head lettuce are blanched because the sun couldn’t get at them. That’s the reason for the milder taste and lower nutritional value.
Hot weather, especially hot nights, is the worst thing for head lettuce; instead of making a head, it tends to go to seed and acquire a bitter taste in the process. Fulton, Great Lakes, and Imperial are varieties of crisphead lettuce. Space them 8 to 18 inches apart, wider for bigger heads
Looseleaf.Looseleaf lettuces are the easiest to grow, the hardiest in hot weather, and the most nourishing. Slobolt is
a famous hot-weather variety; Oak Leaf and Salad Bowl are 2 others. Once you’re used to leaf lettuce, iceberg lettuce is
almost too bland to bear. Leaf lettuce has at first experience a stronger taste, but you can soon get used to it and learn to love it.
Leaf lettuce is ready long before the others, in 40 to 45 days, whereas head lettuce takes 80 to 95 days and needs all of it cool. There are many different varieties of looseleaf lettuce, including Simpson, Grand Rapids, and Salad Bowl.
Romaine. Also called “cos,” this lettuce comes in several varieties such as Paris White, Valmaine, and Parris Island. Romaine leaves grow out of a tight central bunch and straight up instead of curling into a ball or waving loosely.
It’s often planted in late summer or fall in warm-climate places to avoid the heat. Plant 1/ 2 inch deep, 1/ 2 inch apart if you’re going to transplant. Thin or transplant to 8 inches apart. Romaine varieties do best in the Pacific coast climate, but there’s a limit to how much rain even romaine can appreciate, so consider a tunnel cloche.
When to Plant In spring, plant hardy lettuce varieties at the same time as peas-as soon as you can get seed into the ground in the spring. They can endure some early freezes. If not, since seed’s cheap, plant again. But leaf lettuce or any of the other non crisp head lettuces are very perishable once harvested from the garden, and they don’t last in the garden very long-an average of only 3 weeks.
The answer to that is succession planting about every 2 or 3 weeks. With succession planting plus a cold frame, you can have lettuce every month of the year if you live in the South, and fresh lettuce for about 8 months of the year in a climate like the Midwest.
Winter Lettuce. To grow winter lettuce where it freezes, plant it in the garden in late summer (or in your cold frame in early fall), and then transplant to the cold frame right before first frost. There it will keep producing for some time.
You can plant a fall crop in late July, another in early August, another in late August, and maybe even another in September. To save your latest crop during a frost, dig up plants, transplant them to pots or flats, and install in a sunny window inside your house, where they’ll produce some more.
Avoiding Bolting. Lettuce is one of the seed makers that is triggered to mature by the long daylight periods of early summer. That means if you live in a warm part of the country where they grow lettuce all winter, and you plant your seed in October, your lettuce won’t make seed until the following summer.
How to Plant. Lettuce likes deeply worked, crumbly soil that you have manured or composted the fall before, because it has a puny root system that doesn’t hunt for food effectively. The Cook’s Garden offers many lettuce varieties, but every catalog has some.
You can plant lettuce in the garden or start it indoors and transplant when in the 4-leaf stage. But I’m just too lazy to start it indoors and transplant when, with just a little more time, it will grow outdoors. Plant1/4 to 1/ 2 inch deep. For containers, put 1 plant in a 8- inch pot, 4 in a 12-inch pot. Their shallow roots can manage in a pot or flat only 6-8 inches deep. But plant several seeds and then thin.
Sun. For very hot weather choose loose leaf lettuce. But any lettuce seed is harder to sprout in hot weather. It helps to cover the newly planted seed with burlap or wet sawdust and keep it wet until after sprouting. Later you can shelter the lettuce from the sun by stretching burlap on upright sticks over the row like a light roof. In fact, professional
growers grow lettuce under cheesecloth or fish netting laid over slats to cut back the sun’s heat as much as 45 percent.
They use a photographic light meter as a guide to getting the right amount.
Water. Lettuce needs water when the leaves begin to droop. If it doesn’t rain, you’ll have to irrigate. Base-type watering is a better irrigation for your lettuce than water sprinkled on because it’s less inviting to bugs than moisture between the leaves. But sprinkling works if that’s what you’ve got.
Air. Any lettuce will stand up better under heat if it is well thinned and air can get in there and circulate. When any kind of lettuce is crowded, the leaves may start to rot in heat. Then bugs move in by the millions. (Uncrowded lettuce has bugs too, but only some walking around that you can easily rinse off.) Speaking of pests, if slugs are a problem, install toads and leopard frogs. They like to rest under small piles of old hay or mulch during the day and hunt (slugs!) at night.
Thinning. Lettuce thinnings are good to eat-just cut off the root-so it helps your salad supply to thin in stages, as the plants need more room and as you need more lettuce! When thinning, be sure and pull the plant up root and all, because if you leave the root in there, it will try to grow again and pull nourishment from the other plants.
Harvesting. The nicest time to harvest in hot summer is early in the morning, before either you or the plants get hot. Then you wash your lettuce and put it in the refrigerator until you use it. If you cut lettuce leaves away fairly early in a plant’s lifespan and it doesn’t need thinning, keep watering; it’ll keep growing more leaves for a while.
Drying. There’s no point in freezing or canning lettuce. Some people dry it, though. To do that, use tender inner leaves. Shred the leaves. Blanch until wilted. It takes about 1 1/2 minutes in boiling water. Drain.
Spread thinly over deny drator trays or sun-drying trays. Dry at 120T in a dehydrator or oven. Stir and rotate trays once in a while. When dry enough, a cool shred will crumble when rubbed between your fingers. Takes about 8-12 hours in a dehydrator, 2 or 3 days in the sun. Use dried lettuce in soups and in other recipes.