The Best Heat-Tolerant Vegetables to Grow in Your Summer Garden
This summer is predicted to be even hotter, with record temperatures across the U.S. starting in June. While traditional summer crops require warmth, so we wait until summer to grow them, extreme heat waves or heat domes are a different matter.
Plants exhibit a number of behavioral responses when under heat stress. They may wilt, which is, as it sounds, due to lack of water. The leaves will droop, and the solution is not necessarily more water, but allowing the plant to ride out the surge in shade if you can provide it. Plants may bolt, which is when they stop producing leaves or fruit and instead, thinking they have reached the end of their life, produce a flower that will quickly produce seeds. Once that flower has emerged, which is where the plant focuses all its energy, the fruit and leaves will turn bitter. Unfortunately, there is nothing you can do to “solve” the bolting problem other than ripping the plant up and starting over.
And heat isn’t the only threat: Fruit and leaves can also get sunscald, which is essentially sunburn. You might see these spots on tomatoes and squash that appear white instead of red like on human skin. In most cases, plants will survive sunscald, but it puts extra stress on the plant and makes it more susceptible to other garden threats, like disease.
The best solution is to choose plants that will tolerate extreme temperature changes, and then give them some support: water evenly, shade the plants in the midday sun if possible, and avoid planting, replanting, or fertilizing during extreme temperature changes, as these are all stressful for the plants.
Greens That Will Survive a Temperature Swing
While there are bolt-resistant lettuces you can grow, a true heat dome is simply too stressful, and most lettuces will go to seed. For heat-tolerant greens, consider kale , which is hardy in both extreme cold and heat. Collard greens, known for their greens, will also survive a heat wave without wilting, which is why they’re popular in the South. A crop you may not have heard of is Malabar spinach . While traditional spinach is a spring and mid-season crop and won’t grow well in even an average summer, Malabar (which is not actually related to true spinach) is a vining plant from India that tastes surprisingly similar and has become popular due to its hardiness.
Okra and corn feel right at home in the heat
Looking at crops that were popular in areas that are warmer than we are used to is a good strategy for finding vegetables that will withstand extreme temperatures. Okra is native to Ethiopia, so heat tolerance is part of the plant’s DNA. Okra sometimes gets a bad rap for being slippery in recipes, but I highly recommend you consider growing it. There are two types of okra: I only recommend planting the spineless variety. The “spines” are the thorns that can make the okra painful to touch and pick.
Corn can be resource-intensive in your garden, requiring a lot of supplemental nitrogen to be productive, but it is also very hardy. Corn can survive temperatures over 110 degrees and still produce a reliable harvest, as long as those temperature swings don’t drag on for too long. Corn, a true summer crop, needs 70 degrees to grow, which is why you wait until June to plant corn seeds.
Climbing plants such as luffa, tepary beans and spring beans
To be fair, most people don’t eat loofah (though you can); instead, they know it as loofah , a spongy material used in “natural” cleaning. But loofah is actually a type of climbing gourd that will grow abundantly, loves the sun, and thrives in prolonged heat. When the fruit is allowed to dry on the vine, the pulp can be scraped off, leaving a loofah that looks just like the loofah you bought, and is ready to use immediately.
There are many climbing beans (beans that climb, as opposed to bush beans, which do not climb) that originated in hot climates and will thrive during periods of extreme heat. For example, tepary beans : These beans are native to the southwestern United States and Mexico, and will spend the summer climbing and producing pods. Harvest them in the fall before the rains begin, and store them as dry beans.
Yardlong beans are closer to green beans. Still a trailing bean, they can produce beans that are over a foot long, as their name suggests. These summer stars prefer less water, and they will thrive anywhere they have support, such as a trellis.
Soybeans need warmth
Although soybeans are bush beans rather than runner beans, they are easy to grow if you have enough warmth. These sun-tolerant plants produce a limited number of pods per plant, so they must be grown in groups, but they require little to no support other than watering. Harvest the pods and eat the beans steamed like at your favorite Japanese restaurant, or dry them to make soy milk or tofu.
Zucchini and melons love warmth.
There are two types of squash: summer and winter. Summer squash includes crops like zucchini, yellow squash, and pumpkin. Winter squash includes crops like acorn squash, butternut squash, spaghetti squash, and more. Both types of squash are traditionally grown in the summer, and both are surprisingly heat-tolerant. While some fruits can get sunburned, squash is famous for providing shade with its large leaves, and these will not only take care of most fruits by covering them, but will also protect nearby plants by shading them.
If you keep your melons separate from cucumbers and squash to prevent cross-pollination, your vines will likely survive the heat wave, following the same rules as squash: look for fruit that is exposed to the sun and protect it from sunburn, but the plant will generally cope on its own.
Sweet potatoes are made for high temperatures.
Native to Polynesia, sweet potatoes are a great crop for beginning gardeners. They are easy to grow from seedlings (called cuttings) of any sweet potato you bring home from the store. Once planted, they produce abundant above-ground vines that flower spectacularly while the potatoes grow underground for more than 120 days. These plants not only tolerate, but thrive in the heat.