Best Lettuces for Heat and Cold
Researchers at Colorado State University set out to find which lettuce varieties handle summer heat the best. The Bolting Resistance Project used organic growing practices and tested more than 50 varieties. Several clear winners emerged over the course of the project, and they are listed in this table, along with two varieties that withstand chilly spring and fall temperatures.
'New Red Fire'
29 baby size, 55 full size
Dense plant with frilly red leaves that fade to green at the base.
Slower to bolt than other red lettuces.
28 baby size, 49 full size
A lime green, cold-hardy oak leaf. Perennial favorite for spring and fall plantings.
Frost-tolerant, but bolts during the heat of summer.
Pale green, frilly leaves with long harvest period.
Very slow bolting for leaf lettuce.
Dark green leaves form a very large head.
Resists downy mildew, bottom rot, and tip burn.
28 baby size, 54 full size
Upright, densely packed head with dark green leaves and a pale heart.
Grows well in spring, summer, and fall. Frost-tolerant.
Heads grow 8 to 12 inches high and wide with dark green, crinkled leaves and a pale, crunchy heart.
Holds for up to three months in summer heat.
28 baby size,
48 full size
Reddish green, shiny leaves. Practically boltproof.
Resists tip burn and bottom rot.
28 baby size, 48 full size
Green, crisp, mild-flavored leaves. Excellent performance in spring, summer, and fall. Resists tip burn and bottom rot.