Lettuce grows best in cool weather, so most home gardens plant it in early spring, pick it in late spring to early summer, and then throw it away in favor of other vegetables in the middle of summer.
As the days get cooler in the fall, some gardeners might plant a second crop of lettuce. But most gardeners don’t grow lettuce at all in the middle of summer; instead, they focus on warm-season vegetables. Smart gardeners put lettuce next to warm-season vegetables like tomatoes. This way, when the lettuce is done in early summer, the warm-season vegetables have already taken over the garden.
Lettuce grows best in a temperature range of about 45 to 75 degrees. In weather hotter than that, the leaves become bitter to the taste. If leaf lettuce bolts, which means it starts to send up flower stalks, that means the season for growing lettuce for food is over. Leaves harvested after this point will be quite bitter to eat.
But here are some ways in which you can keep lettuce plants producing throughout the summer.
Lettuce is a cool-season crop that thrives with ample sunlight. But exactly how much sun does lettuce need for optimal growth? The amount varies slightly between lettuce types, with some more shade-tolerant than others. With the right conditions, you can grow lush, productive lettuce even in partial shade.
Lettuce Preferences: A Light-Loving Leafy Green
Lettuce naturally grows as a winter and early spring crop before summer heat triggers bolting. This growth habit gives us a major clue to its light requirements. Lettuce evolved to take advantage of increasing daylight during the cooler seasons.
Given the choice, most types of lettuce prefer full sun. Full sun generally means at least 6 hours of direct unfiltered sunlight daily. If possible, aim for 6-8 hours per day. This intensity and duration of light allows lettuce to maximize photosynthesis and growth.
With insufficient sunlight, lettuce becomes leggy and stunted as it reaches for light. It may also develop a mild, less flavorful texture. Slow growth makes it more vulnerable to pests and diseases as well.
Growing Lettuce in Partial Shade
While full sunlight is ideal, lettuce can still thrive with 4-6 hours of sun daily. Providing bright light is more important than maximizing every hour of direct sun.Filtered or dappled shade beneath a light tree canopy often works well
When planting lettuce in partial shade:
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Select more shade-tolerant varieties like red leaf green leaf, or oakleaf lettuce. Romaine and butterhead types need more light.
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Opt for smaller, loose leaf types over large heading lettuces. They are less prone to bolting and bitterness in shade.
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Seek out the sunniest spots in your yard that get at least 4 hours of direct sun, preferably in the cooler morning. East-facing spaces are perfect.
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Use reflective mulches like aluminum foil or Mylar sheeting to bounce more light onto plants. White gravel mulches also help.
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Supplement with grow lights if possible, especially for starts and younger plants. LED grow lights work beautifully indoors or in greenhouses.
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Harvest lettuce promptly when mature, before prolonged shade can diminish texture and flavor. Frequent cut-and-come-again harvests boost productivity.
Sun-Loving Lettuce Varieties to Try
If you can offer mostly full sun, some lettuce varieties that will thrive include:
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Iceberg – Classic crisphead lettuce forms tight dense heads. Needs at least 6 hours of direct sun.
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Butterhead – Buttery, loose heads with tender texture.prefers 8 hours sunlight. Green Boston and red-tinged Bibb varieties available.
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Romaine – Upright heads with crisp, succulent leaves. Grows well with 6-8 sunlight hours. Heat tolerant.
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Summer Crisp – Also called French crisp. Heat-resistant crisphead type. Needs 8+ hours of sun.
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Green and Red Oakleaf– Beautiful loose leaf lettuces withlobed leaves. Tolerates some light shade.
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Lollo Rossa – Frilly red leaves form loose heads. Addsvibrant color. Likes 6-8 hours of sun.
Top Shade-Friendly Lettuce Varieties
When sunlight is limited to just 4-6 hours per day, choose these more flexible lettuces:
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Red Sails – Frilly and slightly crisp red leaf lettuce. Loose leaf type suitable for partial shade.
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Green Leaf – Classic loose leaf with ruffled green foliage. Handles shade better than crisphead types.
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Simpson Elite – Fast-growing green leaf lettuce. Loose leaves stay tender even in low light.
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Salad Bowl – Blend of green and red oakleaf types. Stands both heat and shade fairly well.
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Galactic – Unusual green romaine lettuce with glossy puckered leaves. Tolerates shade and resists bolting.
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Freckles – Spotted green leaves on loose heads. Adds visual interest in shade gardens.
Final Thoughts on Lettuce and Sunlight
While lettuce performs best with abundant sunlight, gardeners can still achieve good results in partially shaded sites. Focus on loose leaf and oakleaf types suited for 4-6 hours of sun. Gardening under shade covers or trees does limit options but with the right varieties and care, you can enjoy homegrown lettuce even in low light conditions.
When to Plant Lettuce for Summer
Lettuce can be planted as soon as the soil can be worked in the early spring. The best temperature for lettuce seed to germinate is between 70 and 75 degrees Fahrenheit, but it depends on the type you plant. Seedlings usually emerge between seven and ten days after planting.
Provide Some Shade
Put your lettuce in the shade of taller plants, like corn or tomatoes, or even plants that grow up walls, like cucumbers and squash. This can be done when you first plant seeds in the spring or whenever there are empty spots in the garden that need to be filled. Lettuce needs more sun in the cool spring than it does in the hot summer. Placing lettuce plants near taller plants, like tomatoes, will give them full sun for six to eight hours in the spring, when the tomato plants are still short, but will protect them from the hot summer sun. Sun cloth hung from poles above the lettuce plants can also help shade them and keep them from bolting too soon.
Does lettuce need full sun?
FAQ
Does lettuce grow better in shade?
How much direct sunlight does lettuce need?
How often should I water lettuce?
Is my lettuce getting too much sun?
Does lettuce need full sun?
If you’re growing lettuce during cooler portions of the year, it will need full sun. This will provide adequate lighting for the crop. However, the trick with lettuce is it prefers to grow in cooler temperatures. If you’re trying to grow lettuce when the temperatures are beginning to warm up, you might need to choose partial sunlight.
How much sun does romaine lettuce need?
Romaine lettuces need eight hours of full sun every day. Leaf lettuce can get by with as little as four hours of full sun every day but they will grow better with six hours of full sun every day. However, those are just basic requirements. You also need to consider the age of the lettuce plants you are growing to get a better picture.
Can lettuce grow in indirect sunlight?
Lettuce can grow in indirect sunlight, but may not grow as fast. It won’t die from not having full sun, but indirect light should then be provided for the entire day. A combination of indirect sunlight and shade, with no direct sun at all, may result in a lettuce plant that fails to thrive to its fullest capacity.
Do lettuce plants wilt if they don’t get full sun?
In some cases, your lettuce plants will develop very few leaves if they don’t get at least 6 hours of full sun exposure per day. Lettuce may also wilt and develop yellow spots if sun-deprived. Opt for an area of your garden that gets a minimum of 6 hours of full sun to eliminate all these problems.