Lettuce is one of the best vegetables to grow in containers, indoors or out. It is easy to grow. It does not require a large container. You can grow lettuce to maturity in a pot just 4 to 6 inches (10-15 cm) across.
Grow lettuce outdoors in pots or boxes on doorsteps, porches, patios, balconies, and rooftops. Grow lettuce indoors on a windowsill or under lights.
Lettuce can be grown in its own container or in a large container at the feet of long-maturing plants such as tomatoes, corn, and eggplants. There are many excellent varieties to choose from, but there are four basic types:
- Head lettuce (like the lettuce you buy in the grocery store) requires 80 to 85 days to mature. It has a tight, round head.
- Butterhead lettuce (also known as Boston or bibb) matures in 65 to 80 days. It forms small, open heads.
- Loose-leaf lettuce matures in 40 to 45 days. The leaves are loose and easily separated.
- Romaine lettuce (also called Cos) matures in 70 to 80 days. It forms long, lightly folded heads.
Lettuce is a cool-weather crop. Choose a variety that will mature before warm summer weather. Loose-leaf lettuce varieties are the quickest to harvest.
Container Size for Growing Lettuce
- Grow lettuce plants 4 to 10 inches (10-25cm) apart. Choose a container that will allow you to plant as many plants as you need.
- Choose a container that is at least 6 to 8 inches (15-20cm) wide and 6 to 8 inches deep. This will accommodate a mature lettuce plant and its roots. The length of the container is determined by the number of plants you want to grow.
- You can grow one lettuce plant to maturity in a 6-inch (15cm) pot. Loose-leaf lettuce leaves can be harvested whenever you need them.
- Lettuce can be started from seeds or transplant seedlings. You can purchase seedling at a garden center or grow your own.
- Plant head lettuce 10 inches (25cm) apart.
- Plant butterhead lettuce 4 to 5 inches (10-12cm) apart.
- Plant loose-leaf and romaine lettuce 10 inches apart if you plan to harvest the leaves cut-and-come again over a period. If you plan let these loose-leaf or romaine types grow to maturity, plant them 6 inches apart.
- Cover lettuce seed with ¼ to ½ inch of soil.
Lettuce Planting Time
- Lettuce is a cool weather crop. Lettuce will go to seed in hot weather. Time lettuce planting so that plants mature in cool weather.
- Start lettuce in early spring. Make plantings at two-week intervals for a continuous supply of greens.
- Plant lettuce in late summer to mature in autumn outdoors.
- Lettuce grown indoors can be planted at any time of the year. Plants can be brought to maturity under lights or can be moved outdoors when the weather is cool, but not cold.
Growing Lettuce Indoors Under Lights
- Grow lettuce indoors under two 40-watt fluorescent tubes.
- Feed plants growing indoors every two weeks with a liquid all-purpose fertilizer.
- Leaves that turn yellow likely need a supplemental feeding.
- Harvest head lettuce when the center feels firm.
- Harvest loose-leaf, butterhead, and romaine lettuce at maturity or as you need leaves, cut-and-come again.
Lettuce Varieties to Grow in Containers
- Great Lakes (90 days). Good quality heads; stands up to warm weather and is slow to go to seed.
- Iceberg A (80 days). Heirloom with medium head and fringed outer leaves; thrives in cool weather.
Butterhead (also known as Boston or bibb)
- Butter King (70 days). Large butterhead, heat resistant.
- Buttercrunch (75 days). Compact, heavy head.
- White Boston (80 days). Tender heirloom with classic mild flavor and buttery heart.
- Oakleaf (45 days). Heat-resistant heirloom; leaves shaped like oak leaves.
- Salad Bowl (50 days). Crinkly leaves; All-America winner for its adaptability; heat resistant.
- Red Sails (55 days). Easy to grow; burgundy leaves; slow to bolt; All-America Selection.
- Early Prizehead (45 days). Tender loose heads; bright green leaves.
Romaine (also called Cos)
- Paris Island Cos (76 days). Firm heads to 10 inches high; heat resistant.
- Paris White Cos (83 days). Light green leaves; heat resistant.
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