Growing Lettuce

Lettuce is a cool-season crop, usually grown from seed planted in the garden four to six weeks before the average date of last frost. Long, hot summer days will make the plants bolt. If your area has a short, hot growing season, start head lettuce from seed indoors eight to ten weeks before the average date of last frost; transplant as soon as possible so the plants will mature before the weather gets really hot.

heads of lettuce
Lettuce is a cool-season crop.

Sow succession crops, beginning in midsummer. In climates with mild winters, grow spring, fall, and winter crops. If you are direct-seeding lettuce in the garden, sow seeds 1/4 inch deep in wide rows. When the seedlings are large enough to handle, thin leaf lettuce to 8 inches apart and head lettuce to 12 inches apart. Thinning is important: Heading lettuce won't head, and all lettuce may bolt if the plants are crowded. Lettuce needs well-worked soil with good drainage and moisture retention. Always keep the soil evenly moist. Don't let the shallow-rooted lettuce plants dry out.

Harvesting Lettuce

As the lettuce grows, either pick the outer leaves and let the inner leaves develop or harvest the whole plant at once by cutting it off at ground level. Try to harvest when the weather is cool; in the heat of the day the leaves may be limp. Chilling will crisp the leaves again.

Lettuce Growing Tips

These tips will help you grow crisp, delicious lettuce:
  • Raised beds covered with heavy-duty floating row covers can provide protection from frosts and light freezes in early to mid-spring and mid- to late fall, or even winter in mild climates.
  • Cold frames, heated by the sun, make it possible to grow lettuce earlier in spring and later in fall or winter. Cold frames are translucent rectangular boxes, about 2 feet wide, 4 feet long, and 18 inches high. The top is hinged to open so you can tend plants inside or cool the cold frame on mild, sunny days. Plant seeds or seedlings of lettuce in the frame and close the lid to hold in the heat.
  • A hot bed, which is a souped-up cold frame, is a great place for winter lettuce. Lay a heating cable under the cold frame. Cover with wire mesh to prevent damage to the cable and top with a layer of sand mixed with compost.
  • For an extended lettuce harvest, pick the largest leaves from the outside of the plant and allow the younger inner leaves to continue growing. But when springtime weather begins to get warm, you need to take the opposite strategy. Cut off the entire plant before it begins to send up a flower stem (a condition called bolting) and turns bitter.
  • Get twice the harvest by planting a lettuce and tomato garden in an 18- or 24-inch-wide pot. You can pick the lettuce as it swells and leave extra growing room for the tomatoes. Here's how to proceed: Fill the pot with a pre-moistened blend of 1/3 compost and 2/3 peat-based potting mix. Plant several leaf lettuce seeds or small seedlings around the edge of the pot and a tomato seedling in the middle. Place the pot in a sunny, frost-free location. Water as needed to keep the soil moist, and fertilize once a month or as needed to encourage good growth.
Keep reading to learn about the many varieties of lettuce.

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