Because it has the propensity to bolt, or produce a central stalk that is composed of blossoms and seeds, and turn bitter when the temperature hits 80 degrees, lettuce is often thought of as a crop that is best grown during the cooler months. Nevertheless, certain types of lettuce can withstand heat better than others. The most effective strategy for ensuring a bountiful harvest of leafy greens despite the high temperatures of summer is to choose kinds that can withstand the heat and to plant them in shaded areas. A sun-blocking building, tall crops such as corn, pole beans, and tomatoes, or a shade cloth draped over supports and rolled at the sides to allow air circulation are all good places to plant lettuce for a bountiful harvest in the middle of the summer. Other options include planting lettuce close to a water source, which helps the lettuce retain its moisture, or planting lettuce beneath a shade cloth.
The “cut-and-come-again” technique of harvesting lettuce is an ideal option for heat because the leaves are harvested early, before the plant has time to bolt. This makes the approach a great choice for growing lettuce in hotter climates. This technique may be used with any kind of butterhead or loose-leaf lettuce that you choose. Take young leaves and snip them off about an inch from their stems. Wait for new leaves to develop in their place, and then take another harvest.
The “cut-and-come-again” lettuce known as “Buttercrunch,” which has a flavour that is both rich and mild, can withstand exceptionally high temperatures. The greatest results may be achieved by providing consistent moisture to the seeds, shielding the young plants from an abundance of light, and pruning the leaves while they are still relatively young.
In addition to being able to withstand high temperatures, the fact that lettuces belonging to the Crisphead family, of which ‘Summer Crisp,’ also called ‘French Crisp,’ and ‘French Batavian,’ are very crisp, sweet, and juicy makes them an ideal summertime delight. You may harvest ‘Summer Crisp’ at any stage of development, from baby to full head, and assure that you will have repeated harvests by replanting it every three weeks.
Try the bright green, oval-shaped leaves of ‘Jericho,’ a romaine that was produced in Israel and is known for its flavour despite being exposed to the harsh desert heat. Another excellent option for crisp temps is ‘Anuenue,’ which is a kind of romaine lettuce that was created in Hawaii by the Hawaii Agricultural Experiment Station. The open-hearted French variety known as ‘Craquerelle du Midi’ has a flavour that is comparable to that of a ‘Buttercrunch,’ but the leaves on this variety are a little bit higher. The variety got its name from the fact that it thrives in the noon heat of France.
‘Red Sails’ has green and red-bronze leaves, ‘Black-Seeded Simpson’ has ruffled leaves, ‘Kinemontpas’ has pale green leaves, ‘Royal Oak Leaf’ is tender and deeply lobed, ‘American Salad Bowl’ has lime-green rosettes, and ‘Green Vision’ has glossy dark-green leaves. All of these varieties are good candidates for growing in hot weather. Both ‘Lollo Biondo’ and ‘Lollo Rossa’ are ornamental lettuces that have leaves that are highly curled and will also thrive well in warm temperatures. When you combine heat-loving veggies with lush lettuces, you may create a lovely garden in which the vegetables serve a dual purpose by also providing shade.