Tips for how to grow this early-season garden favorite.
Sunlight: Full sun to partial shade
Maturity: 40-50 days
Height: 6 to 18 inches
Spacing: 3 to 4 inches apart, 12 to 18 inches between rows
Home gardeners are growing lettuce for its edible foliage which is 90% water, but offers plenty of vitamins A and B. A cool season annual, lettuce is a member of the Asteraceae family and has been cultivated for ages, perhaps longer than any other vegetable crop.
Fact: The average American eats about 30 lbs of lettuce each year.
Lettuce will require partial shade in warm climates, rich, sandy soil and regular water. Work the soil thoroughly (break up any clumps and remove debris) prior to planting. If planting seeds, rake the surface smooth. Transplants can tolerate a rougher planting bed. Dig in plenty of garden compost and soil amendments rich in nitrogen to promote good leaf development.
Tip: Consider adding kelp meal to planting beds. It’s chock-full of micro-nutrients and is especially good for supplying trace minerals to crops that will be consumed.
How to Plant:
Sow lettuce seed directly into prepared garden beds two to four weeks before the last expected frost. Try broadcasting seeds over a wide row and gently raking them in to a depth of 1/8 inch deep. Grow head lettuce, such as romaine and loose leaf varieties, by thinning crops gradually to allow the most robust plants to mature into heads. For a steady supply of leaf lettuce, plant every 10-20 days and remember to shade plants in the summer. To promote rapid growth, apply Dr. Earth Nitro Big or other organic liquid fertilizer once or twice during the gardening season.
Avoid high heat and disturbing roots for a bumper lettuce crop. Mulching with a quality organic compost will help deter weeds and conserve moisture loss (see What’s in Commercial Compost).
Once lettuce begins to bolt (go to seed), the leaves will become bitter. Harvest outer leaves to encourage inner leaves to grow. Lettuce is crispest if picked in the morning. Use a pruning knife to cut heads just below the lower leaves, or pull them out by the roots. Head and romaine lettuce mature about 70 days from seed; leaf lettuce matures in about 40 days.
Insects and Diseases:
Use OMRI Listed diatomaceous earth to protect lettuce from earwigs, aphids and slugs which can occasionally cause problems on the crop. Prevent foliage rot by providing good soil drainage and air circulation around crops. Watering on bright sunny mornings will allow the leaves to dry by evening.
Seed Saving Instructions:
There is only a slight chance of cross-pollination between lettuces. As a precaution, separate by 25 feet from other varieties that are going to seed. Allow plants to bolt and form seed stalks. Seed heads may need to be protected from bird damage and rain when drying. Seeds are produced over a 2-3 week period and will require repeated harvesting.