Lettuce for Spring and Summer Heat Resistance

Lettuce butterhead1

Lettuce butterheadLettuce is the most popular leafy vegetable. You can plant enough leaf lettuce for a family of four in a 1-sqaure foot area, enough head lettuce in a 2-square foot area.

Plant spring lettuce between rows of larger crops such as cabbage or broccoli. Lettuce can be sown in the garden as early as four to six weeks before the last average frost-fee date.

Do a thick sowing of lettuce around other spring transplants. The lettuce will grow quickly covering the garden bed doubling as a weed barrier. Thin the lettuce as it grows. Use the tender thinnings for salads.

Leaf lettuces come to maturity in as little as 45 days. Butterhead and romaine lettuces come to maturity in about 75 days.

Summer lettuce crops can be problematic if you live in a hot or very warm summer region. To grow lettuce in the summer select heat-tolerant or slow-to-bolt varieties and used a midday misting to keep the crop cool.

Cool summer lettuce with a spray of water. You can use misters that will adapt to your drip irrigation. Set the misters at about 5-foot intervals and run them for an hour or two on days when the temperature rises into the 80°sF. The mist will alter the microclimate around your crop without over-watering.

Heat tolerant or bolt resistant lettuce varieties:

Buttercrunch butterhead lettuce. Smooth green leaves, heat tolerant. All-America winner. Ready for harvest in 68 days.

Summer Bibb butterhead lettuce. Thick leaves, creamy and firm interior, slow to bolt. Ready for harvest in 77 days.

White Boston butterhead lettuce. Light-green, medium-sized, smooth outer leaves with wavy edges, mild-flavored, good in warm humid conditions. 57 days to harvest.

Black Seeded Simpson leaf lettuce. Older variety, light-green lightly crumpled leaves on large upright plant, heat and drought tolerant. 45 days to harvest.

Red Salad Bowl leaf lettuce. Bronze burgundy red also known as Red Oak with deeply lobed leaves and good heat tolerance. 55 days to harvest.

Salad Bowl leaf lettuce. Lime-green rosettes, deeply notched with delicate tender leaves. Good resistance to bolting. 55 days to harvest.

Oakleaf leaf lettuce. Medium-dark green deeply lobed oak leaf shaped leaves in tight rosettes. Very good resistance to hot weather. 50 days to harvest.

Ruby leaf lettuce. Deep red variety with large frilled savoyed leaves and bright green centers. Good bolt and heat resistance. 55 days to harvest.

Cimmaron romaine lettuce. Deep red romaine, tally cylindrical plants to 12 inches, crisp and tender. Excellent bolt resistance. Use as baby leaf. 35 days to harvest.

Grand Rapids TBR leaf lettuce. Early, leaves frilled, deeply cut, and light green, heat resistant. 45 days to harvest.

Green Ice leaf lettuce. Dark, glossy green, fringed leaves, heat resistant. 45 days to harvest.

Slobolt leaf lettuce. Crumpled and frilled leaves, good warm-weather lettuce. 45 days to harvest.

Great Lakes crisphead lettuce. Large, erect leaves are bright green and fringed, high quality heads, slow to bolt. All-America winner.

Ithaca crisphead lettuce. Firm heads, mild heat resistance, does well in midsummer. 72 days to harvest.

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.

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