Someone who lives outside Napa County recently asked me about my favorite vegetable to grow. My first, immediate answer was lettuce.
It’s not that lettuce is my favorite vegetable, but for Bay Area gardens, lettuce has many qualities that make it worth some space. A cool-season plant that can tolerate some frost, it grows most of the year here. It grows quickly, maturing in about eight weeks from seed to harvestable head, but you can eat leaves and thinnings much sooner than that.
Lettuce is easy to start from seed, either in the ground or in pots, and easy to transplant. It comes in an amazing array of colors and leaf forms, which beautify the garden. If you let lettuces bloom and set seed, they will often self-sow: at least they do in my patch.
The botanical name for lettuce is Lactuca sativa. There are four main types: loose leaf, butterhead (also known as Bibb), romaine (also known as cos) and crisphead. (The familiar iceberg is a crisphead.) All but crisphead types are common in home gardens.
Lettuce has the best texture and flavor when grown in cool weather. Ideal temperature is 60 to 70 degrees. Warm temperatures cause the plants to “bolt,” or send up a flowering stalk, which makes them bitter. Some varieties tolerate warm weather better than others, so read seed catalogs or plant labels carefully for bolt-resistant varieties to grow in summer.
Lettuce prefers garden soil that is fertile, loose and well drained. If that doesn't describe your garden plot, amend your soil before planting with compost and use a balanced fertilizer formulated for vegetables. Always follow package instructions for best results.
Water lettuces a couple of times a week, more often in warm weather. Don’t let them wilt, but avoid over-watering. Soggy soil can lead to disease.
Plant seeds in flats for transplanting, or sow directly in the ground. Lettuce seed is small, so cover lightly with soil and keep moist until seeds sprout. I’ve seen seeds sprout in three to four days when started indoors in flats on a heating mat. Outdoors, depending upon soil temperature, it will take a week or so. I have successfully started lettuce in the ground as early as February in my east Napa garden.
If you have started seeds indoors, or if you are planting seedlings from a nursery, separate crowded seedlings, untangling their roots before planting. I prefer very small transplants, no more than two inches high. Larger seedlings in nursery six-packs are often root-bound or may have been stressed by wilting. Stressed lettuce is likely to bolt sooner. Set plants six to eight inches apart if you want to harvest leaves as they grow, or a bit farther apart if you want to harvest whole heads. The seed packet or label will indicate optimum spacing.
If you sow seeds directly in the ground, you will need to thin seedlings. Begin by thinning to an inch or two apart. As the plants get larger, thin to allow more space between them. Add these thinnings to your salad bowl, or transplant them elsewhere.
Make successive sowings or plantings to extend the harvest. In spring, plant three to four weeks apart. As the weather warms, lettuces will grow faster, so plant additional rounds every couple of weeks. Provide partial shade during warm weather to discourage bolting. You can even plant lettuces in late fall. They grow slowly in the winter months, but they tolerate quite a bit of frost.
Many common pests may feast on your succulent lettuces. Control slugs and snails with diligent hand-picking. (Go out at night with a flashlight.) Earwigs damage young seedlings; set out rolled newspapers at night to trap them, then shake the earwigs out into soapy water in the morning. Birds also are fond of lettuce. Bird netting or row covers can protect your plants.
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With lettuces from your own garden, you can have a different salad every day of the year. And once you have experienced the freshness of home-grown lettuce, you may never want to buy it again.
Save Sunday, May 15, for “Down the Garden Path,” the Napa County Master Gardeners’ garden tour. The tour will showcase seven upvalley gardens owned and maintained by local Master Gardeners. For tickets and more information, visit http://cenapa.ucdavis.edu.
Mobile help desk
Bring your gardening questions to the Napa County Master Gardeners mobile help desk on Sunday, March 27, at Silverado Ace Hardware in Calistoga; on Saturday, April 2, at Home Depot in Napa; and on Sunday, April 3, at Central Valley Builders Supply in St. Helena. Master Gardeners will be available to answer questions from 10 a.m. to 2 p.m.
Join Napa County Master Gardeners for a workshop on “Containers and Raised Beds” on Saturday, April 16, from 10 a.m to noon at the UC Cooperative Extension in Napa. Learn to maximize your limited space by growing ornamentals, herbs and vegetables in containers and raised beds. Register online ucce.ucdavis.edu /survey/survey.cfm?surveynumber=5920.
Napa County Master Gardeners answer gardening questions Monday, Wednesday and Friday, 9 a.m. to noon, at the UC Cooperative Extension office, 1710 Soscol Ave., Suite 4, Napa, 253-4221, or (877) 279-3065.