13 Best Bolt-Resistant Crops For Your Vegetable Garden

As days lengthen and summer heat sets in, many cool-weather crops go to seed before you can enjoy a quality harvest. Lettuce, spinach, radishes, cilantro, beets, and brassicas are common culprits. Once these plants bolt, they send up a central flowering stem that pulls away energy from the leaves or roots. The edible portion of the plant quickly declines, becoming bitter, woody, or even inedible. Fortunately, there are many bolt-resistant vegetable crops that remain edible and delicious even when conditions change.

When lettuce goes to seed, the leaves turn bitter. If a radish bolts, the roots turn woody. When cilantro bolts, the leafy herb loses its distinctive flavor. Stress, drought, hot weather, lengthening days, and improper variety selection are the most common reasons these plants go to seed. Bolting signals the end of an annual or biennial plant’s life, but there are many ways to prevent it. 

Let’s dig into the most bolt-resistant vegetables and how to prolong their harvestability in hot weather.

What is Bolting?

Bolting is a horticultural term for a garden crop that prematurely forms a flowering stalk before you can harvest the edible portions of the plant. The plant appears to “bolt” up toward the sky, or elongate its central growth form, as it shifts its energy toward reproduction. As it channels nutrients and water into flower and seed production, the roots and leaves become less edible. 

Bolting is also called “going to seed,” and it is most problematic in heat-sensitive crops like lettuce, cilantro, spinach, radishes, brassicas (cauliflower, broccoli, kale), and other leafy greens. The plants rapidly grow very tall, and their edible parts become bitter, woody, or otherwise inedible. Once the central flowering stalk skyrockets upward, it is difficult to reverse the plant’s natural tendency to produce seeds.

Why Do Plants Bolt?

While bolting is completely natural, it is frustrating for gardeners who cultivate vegetables for consumption. Fortunately, plant breeders and farmers have worked for decades to develop bolt-resistant crops that are more resilient in the face of environmental stressors. 

These plants are not genetically modified; rather, they have been selected for desirable traits, like resistance to bolting during hot weather. Much like breeding dogs for certain qualities like spotted fur or working behaviors, bolt-resistant crops are bred to put off their flower production until later in the growing season.

What Are the Most Bolt-Resistant Crops?

Heat-tolerant crops tend to be the most bolt-resistant because hot weather does not hinder the edible portions of the plant. Corn, zucchini, peppers, okra, pumpkins, melons, and tomatoes tend to do the best in areas with hot summers because the crops naturally evolved in sweltering heat. Greens like Swiss chard, Malabar spinach, hybrid brassicas, and collard greens are also bolt-resistant in hot weather.

However, you aren’t limited to only hot-weather vegetables. Southern gardeners can still grow bolt-sensitive greens and roots throughout the summer if they are strategic about their variety selection and planting methods. Spinach, lettuce, cilantro, and radishes can grow for long periods without bolting as long as you take preparatory steps. 

If you combine bolt-resistant crop varieties with certain techniques, you can extend the harvests of many cool-weather crops for the entire summer. For example, if you plant a bolt-resistant lettuce cultivar in the cool, dappled shade of a tomato crop, the lettuce may continue growing pleasant-tasting leaves for weeks longer than a standard variety grown in full sun. The plant’s genetics will tell it to stall reproductive growth until later. Meanwhile, the cooler, shadier conditions can trick the lettuce into thinking it is still spring.

13 Bolt-Resistant Vegetables

Hot-climate gardeners tend to have the most frustrations with bolting. Heat-tolerant crops are naturally bolt-resistant because they tolerate, or even prefer, temperatures above 80°F (27°C). If you struggle with bolting, here are some vegetables to prioritize in your spring and summer gardens

‘Long Standing’ Cilantro

Bolting cilantro is one of the greatest garden woes! This iconic salsa crop prefers the cool weather of spring, but we need it most during peak summer when tomatoes are ripening. This seasonal disconnect often leaves gardeners frustrated when cilantro has bolted and gone to seed before the tomatoes are ready!

Although cilantro flowers and seeds are edible (they’re called coriander!), we want to savor the herbaceous lemony flavor of cilantro leaves for as long as possible. ‘Long Standing’ cilantro is the most bolt-resistant variety around, bred specifically to withstand lengthening days and hot weather for longer than any other cilantro.

If you plant this herb in the dappled shade of your tomato trellises, it won’t receive as much harsh sunlight in early summer. Mulch the soil and keep it consistently moist. Regularly snipping the tops will help the plant hold off on bolting for even longer. The leaves should remain harvestable for many weeks to overlap with your tomato harvests. In extremely hot southern climates, you may need to harvest before daytime temperatures reach 90°F (32°C) and freeze the leaves to preserve their flavor for late summer salsa fiesta. 

‘Vivian’ Romaine

Romaine lettuces are often the first to bolt when late spring temperatures turn warm. Lettuce naturally bolts when exposed to longer daylight hours, hotter weather, or both. Romaines are naturally oval or football-shaped, but when they start flowering, they spiral upward with several tall whorls of leaves. Eventually, they’ll produce giant seed stalks with little dandelion-like flowers that turn into wispy white seed heads. The leaves become very bitter and tough, no longer suitable for salads or burgers. 

So what do you grow if you crave tender salads on a hot day or crisp lettuce atop your summer cookout burgers? ‘Vivian’ romaine lettuce is bred for vigorous growth and bolt resistance no matter how hot. It is bolt-resistant and extra dependable in warm climates. The fat emerald-green heads grow up to 12-16” tall and 4-6” wide, dense with large leaves for lettuce wraps or impressive salads.

If you plant several successions of ‘Vivian’ romaine every two to three weeks throughout late spring, you can ensure longer-lasting lettuce harvests. Be sure the plants stay consistently moist, as drought stress can also cause lettuce to bolt. In hot climates, it helps to plant lettuce in a location with afternoon shade, such as an east-facing part of the garden or under the dappled canopy of a taller crop like trellised cucumbers.

‘Great Lakes 118’ Crisphead Lettuce

If you’re not a fan of leafy romaine, crisphead lettuce offers an even cooler crunch when eaten straight out of the fridge. ‘Great Lakes 118 Crisphead’ is a cultivar bred specifically for heat tolerance and bolt resistance. The dense, rounded heads are refreshingly crisp, perfect for summer sandwiches and salads.

As long as soil temperatures are under 80°F (27°C), this lettuce will reliably germinate in warmer gardens. Sow seeds about ⅛” and barely cover them with soil. Direct-sown seeds may be less likely to bolt because they are not exposed to transplant shock. Be sure to provide at least eight inches of space between plants. 

Once they reach a desirable size, you can cut the rounded heads at ground level. For a continuous supply, harvest individual outer leaves instead. If you leave behind the center two inches of the plant, it will keep regrowing. Like many other crops on this list, you’ll find that regularly harvesting lettuce can prevent it from bolting. 

New Zealand Spinach

Standard spinach is infamous for bolting as soon as the days lengthen. After all, spinach is a cool-weather crop that doesn’t fare well in hot climates. But if you still crave deep green, iron-rich leaves, you can plant New Zealand spinach throughout the summer. First discovered in 1770, this spinach alternative is not a “true “spinach, but it has a very similar flavor. The plants are perennial in USDA zones 8 and warmer, and they produce abundantly in the heat.

New Zealand spinach has a particularly high vitamin C content that was once used by sailors to prevent scurvy. The leaves are best harvested young and taste excellent cooked or raw. Virtually insect-free, this crop is easier to grow than regular spinach, and it can handle more drought. 

Sow outside one to two weeks after your last frost and enjoy a continuous harvest of greens all summer long. You can cut up to one-third of the plant, and it will quickly regrow. If you pinch the tips, the plants will become bushier, sending out more branches for leaf production.

‘Robin’ Beet

Bolted beets lose their signature bulbous shape. The roots become awkwardly elongated, and their texture turns pithy or woody, and the leaves become much more chewy and unpleasantly textured.

The elongated flowering stalks look similar to their chard cousins, with bright spindly stems and tall spikes of clustered seeds resembling amaranth. While this can be a great way to collect beet seeds for future plantings, it is a major bummer for gardeners hoping to harvest the roots.

‘Robin’ beet is a more reliable variety with high bolt resistance. This beet was developed for harvesting at “baby” size when the roots are approximately one and a half inches in diameter. The bulbs are sweet, crunchy, tender, and perfectly rounded. They have the signature blood-red beet color and nice tender greens. 

You can plant ‘Robin’ beets throughout early summer when soil temperatures are between 60-85°F (16-29°C). Sow seeds ½” deep and maintain consistent moisture to prevent pithiness (an unpleasant texture). 

If your beets have weird black corky-textured spots inside the roots, you may have a boron deficiency in the soil or an issue with an excessively alkaline pH. This can be remedied by adding worm castings, mixing in boric acid (such as Borax), or lowering the pH with elemental sulfur.

Chinese Sprouting Broccoli

Broccoli is technically a large modified central flower inside a cabbage-family plant. But if broccoli crops bolt prematurely, they won’t develop the broccoli floret heads we love. Bolted broccoli has spindly yellow flowers similar to mustard. While the flowers are edible, they are more bitter and lack the tender, crunchy stems of classic broccoli.

Chinese sprouting broccoli offers an excellent solution! Instead of harvesting one giant head of broccoli from each crop, you can plant Chinese sprouting broccoli and enjoy tender side shoots of broccoli all summer long. Sometimes called kailaan, this vegetable is widely used in Asian cuisine and has sweet, complex-flavored florets with juicy stems. The plants tolerate far more heat than regular broccoli and kale, offering a much longer harvest period.

Chinese broccoli is very popular for stir-fry dishes, but you can also use it in any recipe that calls for broccoli. The vegetable requires less cleanup in the kitchen because you don’t have to cut into a giant broccoli head that leaves little pieces of broccoli everywhere. It’s also nice to enjoy the stems of this sprouting brassica, which have a texture like asparagus when cooked.

Direct sowing is recommended for Chinese sprouting broccoli to prevent bolting. Transplants often prematurely flower due to transplant shock. Instead, put seeds directly in the ground throughout late spring and summer when soil temperatures are between 60-85°F (16-29°C). Consistent harvests prevent flowering. 

‘Celebration’ Swiss Chard

Chard is a biennial crop, which means it takes two years to complete its life cycle. In the first year, plants devote their growth to root, stem, and leaf growth. In the second year, chard naturally bolts to produce flowers and seeds that can restart the life cycle. Fortunately for us gardeners, chard is most often grown as an annual in cultivation. This means we only keep the plants for one year, so they rarely go to seed. In general, biennial crops are the most bolt-resistant because their two-year cycles are wired into their DNA. They are highly unlikely to bolt in the first year of growth.

‘Celebration’ Swiss chard is a blend of rainbow-stemmed chard varieties that can be grown throughout the entire gardening season. Plant a succession in early spring and harvest it throughout the summer. I like to plant another round of chard in late summer to enjoy fresh picking during the fall.

This nutritious green can be grown for full-size leaves or baby greens. Seeds can be sown up to 2-4 weeks before your last spring frost, midsummer, or at least 2 months before your first fall frost for overwintering in mild climates. 

Space the plants at least eight inches apart in rows 18 inches apart. Harvest the outer leaves as needed, leaving the centers to regrow throughout the summer. For baby greens, sow densely like lettuce and cut at ground level once leaves are two to four inches. If you leave the growing tip intact, the leaves will regrow several times as long as there is moisture.

‘Twister’ Cauliflower

Like chard, cauliflower plants are also biennials. This means they are naturally bolt-resistant because they don’t usually go to seed until their second year of growth. Since cauliflower is typically grown as an annual in the garden, bolting is unlikely. However, many gardeners struggle with summer cauliflower in general because the plants dislike heat. ‘Twister’ is a variety that was specifically bred with these issues in mind. 

These plants are heat-resistant and will reliably form a head in warm weather. They naturally wrap or “twist” their leaves around the white cauliflower, shielding it from snow or heat. This means the cauliflower remains pure white and resists wormy infestations. The wrapping can also protect the florets from sunscald that can create unsightly brown spots. 

Plant ‘Twister’ in late spring or mid-to-late summer. Starting indoors and transplanting out is usually best. Spread straw or leaf mulch to keep the soil cooler around cauliflower roots.  If growing in a warm climate, seed in early fall for a winter harvest. Ensure at least two to three feet of space between plants and rows. Overcrowded cauliflower will not produce the nice heads you’re used to buying in the grocery store.

Purslane

Though it is commonly considered a weed, purslane is actually an amazingly delicious and nutrient-dense vegetable. The low-growing rosettes of succulent spoon-shaped leaves often create a ground cover in vegetable beds, sometimes becoming weedy. Fortunately, the plants are very easy to uproot and use as the perfect summer salad green. 

In Mexico, purslane is called verdolagas and is popularly used in salsa verde. Purslane plants are naturally bolt-resistant because they’re accustomed to growing in the heat. The leaves of purslane are considered one of the most nutrient-dense foods on earth, with abundant amounts of antioxidants, trace minerals, and omega-3 fatty acids. 

Purslane is an excellent substitute for bolt-prone greens in summer salads. It is extremely drought-tolerant and literally grows itself without asking for any aid from humans. The leaves have an intriguing salty, almost sour, or zesty flavor reminiscent of watercress or spinach. I love the juicy texture that complements a robust BLT sandwich or a light side salad for summer barbeques. 

If purslane isn’t already growing as a weed in your garden, you can purchase seeds and scatter them on the soil surface. Take care to keep the purslane contained so it doesn’t outcompete your other veggies. I like to grow it in a pot or grow bag in the corner of the garden. Continuous harvesting ensures the plant doesn’t go to seed. A single plant can produce up to 240,000 seeds, so you definitely want to eat as much as you can and then dig it up before it bolts!

‘Walla Walla’ Onions

If you’ve ever harvested a stunted onion with a big green stalk through the center, it likely bolted. Unlike many other crops on this list, onions tend to bolt in reaction to cold weather stress rather than heat. Many consecutive nights under 45°F (7°C) can confuse young onion plants into thinking it’s the end of their lifecycle. To prevent onions from going to seed before they produce the big saute-worthy bulbs that you’re hoping for, you need to choose the right variety and plant at the right time.

‘Walla Walla’ sweet onions are pretty iconic in grocery stores and are even more popular in gardens thanks to the enormous sweet-flavored bulbs. This long-day onion is ideal for northern climates because it begins forming bulbs as soon as the days reach 14-16 hours of sunlight. It resists bolting in cold weather and has some frost tolerance for early autumn freezes. 

Notice how mature onions handle cold with ease, but the baby onion seedlings are the ones you have to worry about. In the event of an unexpected late spring frost, lay floating row fabric over the beds to protect onion seedlings.

‘Walla Walla’ onions take up to 125 days to mature, so if you live in a very cold climate, it’s important to start them indoors in the spring. However, you don’t want to transplant them outside until the soil is at least 60°F (16°C); otherwise, the seedlings lose their bolt resistance. For southern gardeners, choose a short-day onion variety like ‘Texas Early Grano.’

Fortunately, if your onions do bolt, they are still edible. You can dig them up and even eat the flowers (which taste like floral oniony goodness). The main problem is that bolted onions don’t store well. 

Collard Greens

Collards are iconic in southern cuisine for a reason. After spinach, lettuce, and kale have bolted in the summer heat, collard greens are usually the last ones standing! ‘Georgia Southern Collards’ are a bolt-resistant crop for the south and a frost-tolerant green for the north. No matter where you grow them, these plants are seriously hardy. They produce large, cabbage-like, deep-green leaves that make delicious wraps, stews, or steamed side dishes.

Heat is no problem for collards, and they are highly unlikely to go to seed because they are biennial plants grown as annuals. While most summer greens struggle, collards can handle moderate drought and maintain their pretty blue-green color. In the fall and winter, the leaves get sweeter when exposed to light frosts. 

Continuously harvest collard greens throughout the season by gently pulling away the outer leaves. The vigorous centers will keep producing new growth for as long as temperatures allow. Consistent moisture and a bit of mulch keep plants healthy and vibrant. 

Ground Cherries

Add a tropical vibe to your summer veggie garden with ‘Pineapple Ground Cherry.’ Sometimes called gooseberries, these rambling vines are related to tomatillos but have a uniquely fruity, sweet flavor. Ground cherries love the heat, and bolting is not an issue because the plant’s fruits are highly desirable. When they are ripe, they fall to the ground and are easy to clean, thanks to the protective husks surrounding them.

Ground cherries are a southern garden essential because they thrive in the heat while many other crops struggle. You can use the fruits in salsas, jams, and fruit pies. This tropical-native plant is frost-sensitive, so you can’t grow them outside until two to four weeks after your average last spring frost. 

The plants reliably last all summer and produce more mini-tomatillo-shaped fruits than you’ll know what to do with. The fallen fruits should be warm golden yellow and about ½” in diameter. Stake or trellis these for a cleaner, more compact growth habit.

Okra

Okra is one of the most heat-loving vegetables you can grow in your garden. Bolting is not a problem because you actually want these plants to produce flowers and fruits. ‘Clemson Spineless 80’ was developed at Clemson University specifically for growing in the Deep South. The uniquely grooved pods are highly desirable amongst okra lovers, with delicious full-bodied flavor. They are best harvested at three to four inches long for the most tender skins. The pods can become tough if you let them get too big.

Okra is extremely heat tolerant, reliably standing in the garden even through sweltering triple digits. As long as you provide some regular moisture and full sunshine, these plants are the perfect summer vegetable to harvest when many other crops have become inedible due to bolting. Okra flowers are also highly attractive to flowers and add a beautiful ornamental display similar to hollyhocks.