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If you live in an area with temperatures above 80 degrees in the summer, you’ve likely struggled to grow spring crops like lettuce, radishes, peas, cilantro, and brassicas in hot weather. Fortunately, there are several heat-resistant vegetables to grow during scorching summers.
Standard summer crops like tomatoes, cucumbers, squash, peppers, and eggplants all hold up great in the heat. But some vegetables on this list may surprise you!
Growing Vegetables in Warm Summer Months
Sweltering summer gardening poses completely different challenges than harsh northern winters. Before we dig into specific crops, let’s cover some basics.
Bolting
Bolting is a natural process that some plants, like lettuce, broccoli, and even cabbage, will go through to produce seeds. These cool-season crops react to the signal of warmer days by sending up flower stalks which will eventually produce seeds.
This is called “bolting” because the plant suddenly raises its height and “bolts” toward the sky. The result is usually tough, flavorless, or inedible crops. However, many bolted veggies like broccoli have delicious edible flowers (hello broccoli raab!)
Plants naturally bolt at the end of their lifecycle. Cold-weather crops can’t survive the hot days, so before they die back completely, their main goal is to produce seeds for future generations. Regular harvests can slow down the bolting process but ultimately will not prevent it.
The Biennial Advantage
One way to avoid the issue of bolting is to choose biennial crops like brassicas (cabbage, broccoli, brussels sprouts, cauliflower), celery, or onions. Annuals complete their life cycle in one season, but biennials only flower and produce seeds in their second year of growth.
During a biennial’s first year of growth, they do not usually bolt and can be heat-tolerant. Their main goal is to develop leaves and roots to prepare for their second year of growth when they will produce seeds. Some crops are also available in heat-resistant and slow-bolting varieties. Look for these labels in your seed catalog.
Watering and Mulching
Keeping vegetables well-watered and mulched during the heat of the summer will also ensure a thriving plant that produces a productive crop. Mulch helps conserve moisture and keep the soil cooler on hot days.
Plant Timing
Choosing the right variety for your hot climate and planting at the right time improves heat performance. Most of the heat-resistant vegetables will need to be planted only when nighttime temperatures are above 50 degrees. For the most part, they do best in daytime temperatures between 70-85 degrees Fahrenheit.
Cool-weather crops should be reserved for the spring and fall whenever possible.
27 Heat-Resistant Vegetables
These heat-resistant vegetables like to soak up the sun and warmth. Remember, most still require consistent moisture to support their growth through scorching temperatures.
Malabar Spinach
Malabar spinach is unrelated to true spinach but can be used similarly and has a similar flavor. It is named after a region in India where this subtropical vining plant is used in curries and stir-fries. This plant grows very differently than classic spinach.
Rather than growing in a low-to-the-ground bushy habit, Malabar spinach will need a trellis or other structure to climb. This plant can take the heat, but you’ll want to keep the soil moist to avoid bitterness. It can even take the heat of areas like Arizona and New Mexico, where traditional spinach struggles.
Okra
Okra originated in Africa (in Ethiopia) and was made to resist the heat. It is so heat resistant that it has become a staple in the Southern United States, specifically Southern cuisine. Some gardeners love this vegetable but have difficulty harvesting okra because of the spines. There are generally spines on the stems, leaves, and okra pods themselves, which can irritate the skin when they come in contact.
For people who don’t want to battle with the spines, look for a “spineless” variety. These may still have some spines, but few by comparison. Clemson Spineless 80 is a perfect example of a variety of this sort. Even with spineless types, a good rule of thumb is always to harvest okra with gloves and arm protection when reaching into the plant.
Sweet Potatoes
Sweet potatoes were originally considered native to Central and South America, but evidence has emerged that they were first cultivated in Polynesia and brought to the Americas. They are one of the best heat-resistant vegetables, tolerating temperatures of 80 degrees and above.
These delectable tubers need well-draining loose soil to yield in abundance. You can achieve this by loosening soil and adding sand to the planting site to help improve drainage. You can even grow sweet potatoes in large containers like wine barrels. They will need to be in the ground for about 4 months.
Sweet potatoes are very sensitive to cold and do best when planted in the ground once the soil temperatures reach a minimum of 65 degrees. They will grow throughout the summer until the first frost.
Start from sweet potato slips, which can be produced by putting a sweet potato into the water, allowing it to root and sprout a leafy green shoot called a slip. Gently remove the slip from the potato, place it into a glass of water, allow it to form roots, and then plant the slip in the ground.
Summer Squash
Summer squash has been cultivated for over 8,000 years. It is a part of the traditional Native American three sisters garden (which includes corn, beans, and squash). True to their name, summer squashes won’t start taking off until the heat of summer sets in.
They are prolific producers and known amongst gardeners for being given away to neighbors at the height of the season, or else you might end up elbow-deep in zucchini!
In addition to zucchini, summer squashes also include yellow squash, patty pan squash, chayote, and cousa squash. All of these members of the summer squash family enjoy the heat and usually outlast southern summer weather.
Peppers
Peppers originated in Central and South America and are a perfect heat-resistant vegetable for sweltering gardens. Capsicum annum is the original species from which thousands of cultivars have been developed. This includes both sweet peppers and hot peppers.
All peppers need warm weather to grow and produce. In areas with shorter growing seasons, you will need to start pepper seeds indoors 2 months before the last frost day and transplant them out only once nighttime temps are consistently above 50 degrees. Cooler weather can stunt pepper plants.
Peppers favor warm conditions so much that the seeds benefit from a heating mat to help them reliably germinate. During the height of the summer, you’ll want to water them deeply and infrequently, mulch well, and they will tolerate the heat.
Providing afternoon shade in extremely hot areas can help prevent pepper flowers from dropping. In mild climates, you can even overwinter peppers, and they will come back to life when the weather warms up the following season.
Tepary Beans
Tepary beans come in both bushing and climbing varieties. They can handle various poor soil conditions, including alkaline and sandy soils.
These beans can struggle in clay soil because it often holds too much moisture, and they prefer to dry out between waterings. But this tendency to prefer drier conditions makes them drought-tolerant as well as heat-tolerant.
Yardlong Beans
Much like tepary beans, yardlong beans can tolerate poor soil conditions, including arid soils and low rainfall conditions. These beans can take high heat conditions and set fruit in conditions other beans cannot.
However, in drought conditions, the beans will grow short and fibrous rather than long and tender. For the best beans, water deeply and mulch well, and they will handle the heat just fine while producing a bumper crop of beans along the way!
Sunflowers
This North American native flower was cultivated by indigenous peoples in New Mexico and Arizona since 3000 BC. While it is not generally considered a vegetable, the entire sunflower plant is edible, including the leaves, stalks, immature flower heads, and mature seeds.
There is an almost endless variety of sunflowers, including snacking seed varieties grown for their large seeds, similar to those in the bulk section of a grocery store.
Once the roots of sunflowers are well established, the plants do not need much water. Since the birds and squirrels are happy to spread around the seeds, you will see volunteers pop up throughout your garden for years to come.
Tomatoes
This quintessential summer crop is one of the most popular vegetables among backyard gardeners. There is nothing quite like a homegrown tomato. They taste best when picked during midday when the highest amount of sugar is concentrated in the fruits. In my opinion, they taste best when eaten warm from the sun.
Tomatoes and warm summer days and nights go hand in hand; it makes sense that the plants prefer full sun and warm conditions.
Tomatoes do best in a daytime temperature range between 70-85 degrees Fahrenheit. Consistent conditions above 90 degrees Fahrenheit can cause them to struggle, but shade cloth can help them continue to set fruit in even the hottest conditions.
Eggplants
Of the three most commonly grown nightshades (tomatoes, peppers, and eggplants), eggplants love the heat the most! Like tomatoes, eggplants do best in daytime temperatures between 70-85 degrees, but they can also tolerate weather in the low 90s. Prolonged time spent over 95 degrees may cause their flowers to drop, but the plants will survive as long as they have enough water.
There are tons of varieties of eggplants to choose from aside from the standard black beauty (which is similar to what you’ll find in the grocery store).
The small and thin Japanese-style eggplants are just as delicious and even more heat tolerant. The purple flowers of the eggplant add a beautiful color to the garden, and the fruits are delicious!
Corn
Corn has been cultivated all over the Americas for centuries. It is estimated that the wild grass ancestor became domesticated corn about 8,700 years ago in Southwestern Mexico. Modern-day corn is thought to have descended from tropical grass and thus can withstand temperatures as high as 110+ degrees Fahrenheit for short periods.
Although its growth does slow down in temperatures above 95 degrees. This warm-season crop can be reliably grown in temperatures from 70-95 degrees. Corn seeds prefer warm soil conditions to germinate. If the soil is too cold, the seed will rot in the ground before it can sprout.
Cucumbers
With their high water content, cucumbers need consistent moisture to produce crisp, delicious fruits. However, in the right conditions, they are still heat-resistant vegetables.
They tend to be dramatic like most cucurbits and wilt in the heat of the day, but they will perk back up again once the sun begins to set and moves off of the foliage.
Cucumbers do best in daytime temperatures between 70-90 degrees. In prolonged temperatures above 90 degrees, flowering may cease, which will affect the production of fruit. In areas that regularly receive temperatures above 90 degrees, providing your cucumbers with afternoon shade can eliminate this issue.
Swiss Chard
Like Malabar spinach, Swiss chard is another heat-resistant vegetable and a great spinach substitute. Chard is related to beets, and the foliage has a similar earthy flavor, but the texture of the leaves makes it a great stand-in for spinach.
This leafy green can equally tolerate cool weather as well as heat. It can be planted in early spring and grown throughout the summer until the first frost. Grow rainbow chard for a variety of colors in your garden!
Kale
Similarly to Swiss chard, kale can tolerate both cool and hot conditions. This may be surprising since we don’t usually consider this biennial a heat-resistant vegetable.
It can be started in early spring and grown all through the heat of the summer and even past the first frost. It is said that frost improves the flavor of kale by making it sweeter.
The real benefit is that it can be started alongside your cool-weather lettuce, and when they begin to bolt from the heat, the kale will keep growing! One kale plant can provide you with a leafy green all summer long. Be aware that at the peak of the summer, your kale may be slightly more bitter than in cooler weather, but it’s still going to have great flavor.
There are many varieties of kale, including both curly-leaf and flat-leaf varieties. For a pop of color, try growing ‘Dazzling Blue‘ kale, which looks beautiful with its blueish purple stems, or choose a variety pack of seeds if you just can’t decide.
Onions
Onions are often considered cool-weather crops since they are frost tolerant. Onions are biennial and can be left in the ground over winter in the harshest conditions.
They will return in the spring, and in their second year of growth, they will produce a flower stalk and go to seed. Although they can survive extreme cold, they can also tolerate heat.
Bulbing onions are generally planted in the cool spring weather, but they need the long warm days of summer to trigger bulb formation. There are 3 types of bulbing onions:
- Long day onions
- Short day onions
- Intermediate day onions
This indicates the day length required for bulb formation, and which type you grow will depend on the day length in your area.
Rhubarb
Rhubarb is also often considered a cool-weather spring crop, and rhubarb will indeed be one of the first things to break through the soil in the spring. However, it will continue to grow and produce stalks all summer long in the cooler parts of the US.
It does require cold winters and struggles in year-long mild climates, but it can tolerate the brief heat during the summer in USDA growing zones 3-8. It may begin to bolt when the weather gets very hot, but the flower stalks can be cut back, and it will continue to grow and produce.
Tomatillo
Tomatillos have similar care requirements to tomatoes, except they are more tolerant of the heat and even more prolific. When growing tomatillos, plant at least two plants nearby, as most varieties require cross-pollination to produce fruit.
They are fairly heat and drought-tolerant and are less susceptible to blight than garden-variety tomatoes. The ideal temperature range for tomatillos is between 60-85 degrees Fahrenheit.
Ground Cherries
Ground cherries have great heat tolerance and are related to tomatillos. They are also in the Solanaceae family, the same family as tomatoes. Thus, they love the heat!
While they are related to savory vegetables like the tomatillo, ground cherries are known for their slightly sweet tropical taste. They get their name because the fruit falls to the ground when ripe. They are the size of a cherry tomato when mature and are wrapped in a papery skin similar to a tomatillo.
Leeks
Like onions, leeks are often thought of as a cool-weather crop. This is because they are frost tolerant and can be started in early spring and grown well into the fall and winter.
However, leeks must grow for a long season to reach full maturity. This can be done in mild climates over the winter, but in cooler regions with harsh winters, leeks will be started in the spring, grown through the summer, and harvested in the fall.
Most leek varieties will tolerate heat as long as they are provided enough water. If temperatures remain at or below 80 degrees for most of the summer, you can likely grow leeks during the warm season.
Winter Squash
Despite their name, winter squash is not grown during the winter! They are grown just like summer squashes. They prefer a warm season in which to grow and produce fruits. The reason for the name winter squash refers to its long shelf life.
Summer squash has a thin, tender skin that needs to be eaten shortly after harvest, whereas winter squash has a thicker outer skin which allows them to be stored for longer periods over the winter.
Winter squash includes a wide variety of pumpkins, butternut, delicata, acorn, spaghetti squash, and many more! They will tolerate heat just like summer squash and will provide a harvest that, when cured properly, can be stored for the long term.
Hybrid Broccoli
Broccoli is another crop mostly known as a cool-season veggie. This is true 95% of the time. However, several heat-tolerant hybrid varieties of broccoli can be reliably grown through the summer.
‘Lieutenant’ and ‘Sun King’ are two such varieties that can handle the heat without bolting or becoming bitter. So if you find yourself longing for broccoli outside the spring and fall growing seasons, you might consider trying hybrid broccoli!
Luffa
Luffa gourds are a fun addition to any garden. Aside from being left to mature and harvested for use as a shower sponge, they can also be harvested young and eaten like summer squash. They have a long growing season that requires a period of warm weather.
Most luffa gourds need at least 150-200 frost-free days to reach maturity. Luffa are very cold-sensitive, struggle with nighttime temperatures below 65 degrees, and prefer daytime temperatures above 70 degrees. They are heat-loving like most melons and do best in warm growing conditions.
Collards
Like okra, collard greens are a staple in southern cuisine because they grow well in the heat of the southern United States. Collards are technically a biennial, although they are mostly grown as an annual for their edible foliage. Since they are biennial, they can take the heat without bolting because they won’t flower until their second year of growth.
They can be swapped into recipes calling for kale, spinach, chard, or other hearty greens. Like kale and chard, collards can also handle the frost, which means they can be started in spring, grow all through the summer, and into the fall without missing a beat.
Purslane
This plant is often considered a weed, but it’s edible! These plants aren’t picky about soil conditions and can often grow in sidewalk cracks. It makes an excellent ground cover between taller plants.
The leaves are small but succulent, as they are adept at holding onto moisture, which helps them survive the sweltering heat. They do best when temperatures are above 70 degrees and can even thrive above 100 degrees Fahrenheit!
Purslane is an annual, but it will readily self-seed and return year after year. It is a delicious and tender leafy addition to summer salads.
Butterhead Lettuce
Butterhead lettuce is known for being the most heat-tolerant and bolt-resistant of all lettuce. This variety produces loosely formed heads with slightly ruffly leaves and prefers warmer and longer days of summer.
Water deeply and mulch heavily to keep this lettuce happy in the heat. You can harvest individual heads or employ the cut-and-come-again method for continual harvests. This is a great addition to the summer salad, along with chard, kale, and collards. This will give you a variety of fresh greens to enjoy all summer long with your tomatoes and cucumbers.
Amaranth
Another spinach substitute with a similar flavor is ‘Edible Red Leaf’ amaranth. Amaranth loves the heat and is drought-tolerant once established.
It makes another great summer salad addition once the spring greens have begun to bolt. It can be grown for its edible foliage or left to fully mature and grown for its seeds which are 13% higher in protein than most other grains and can be eaten and prepared similarly to quinoa.
Carrots
This is another crop that is generally thought of as a cool season spring or fall crop. However, certain varieties, such as ‘Shin Kuroda,’ are quite heat-resistant. This sweet carrot produces a 5-inch tapered root with no trouble standing up to the summer heat.
Keep seeds evenly moist until they have sprouted. Covering seeds with burlap or a board can help retain moisture and increase germination, especially in the heat. Once they have emerged, provide plenty of water, and they will do just fine throughout the heat of summer.
Final Thoughts
I hope this gives you the confidence to try growing some of these vegetables even in the heat of the summer. Remember to keep plants well-watered, mulched, and harvested regularly to prevent the plant from attempting to go to seed and/or bolting. Provide shade cloth when needed, and remember that choosing the right variety for your climate can make all the difference!
