Plant These 15 Vegetables in May

Say goodbye to spinach and kale and hello to your favorite summer crops! At last, finicky spring weather has passed, and the warmth of May blankets most of the northern hemisphere. This month is perfect for planting all your warm-weather vegetables in the garden. 

From melons to tomatoes to peppers to sweet corn, there are hundreds of varieties of heat-loving crops eager to flourish in the coming months. While southern gardeners need to prioritize heat-tolerant and bolt-resistant crops, northern growers can finally embrace the freedom to move their frost-tender seedlings outdoors. 

Let’s dig into the 15 best vegetables to plant in May based on your growing zone. As long as you have enough rainfall or irrigation, these vegetables will thrive in the warm soils and abundant sunshine of May.

What Vegetables Should I Plant in May?

May usually marks the “safe zone” for northern gardeners eagerly awaiting spring. As the last frost dates pass, it’s finally safe to plant tender crops in the ground without protection. In southern zones, this is prime time for sowing heat-loving vegetables that can withstand the intense summer sunshine. 

Here are the best vegetables to plant in May by zone:

15 Vegetables to Plant in May

May marks the end of spring and the start of summer. With southern gardens blanketed in color and northern growers finally free to put away their snow boots, May is one of the best times of year in the garden. While zones 8 and warmer should have all their summer crops in the ground, frigid zone 3 just reached its expected last frost date. 

Southern gardeners can plant the next successions of tomatoes and zucchini while preparing warm-weather sweet potatoes, okra, and peppers for the sweltering months ahead. Northern gardeners can pull out their cool-weather crops and replace them with beans, winter squash, melons, tomatoes, eggplants, and sunflowers. 

Here are 15 prolific heat-loving vegetables to plant in May for vibrant summer harvests.

Specialty Cantaloupe

Grocery stores have given cantaloupe a bad name because the standard commercialized varieties often lack flavor and quality texture. In the garden, you don’t have to worry about storage or transplant, so you can grow a more delectable diversity of specialty melons that will change your mind about cantaloupe forever.

Also known as muskmelons, these small, ultra-sweet fruits are considered delicacies in France. I’ve never liked store-bought cantaloupe, but I wouldn’t go a summer without growing these fragrant cantaloupe cultivars! Better yet, small melons are particularly suitable for areas with shorter growing seasons and cooler nights because they don’t require the long, hot days that watermelons need to thrive.

In zones 5 and warmer, you can direct sow melon seeds outdoors throughout May as long as your soil temperatures are above 70°F (21°C). Use a soil thermometer probe to check before seeding. 

In zones 3 and 4, you may need to use row cover or start the seeds indoors in early May inside biodegradable pots or soil blocks. Remember that the cucurbit family (including melons) is very sensitive to transplant shock from root disturbance, so you don’t want to start them in regular pots. Transplant out in two to four weeks and protect from cold nights.

Best Varieties

‘Charentais’ is the queen of French heirloom cantaloupes. Unavailable in stores due to its fragile skins, these melons are a delicacy reserved only for adventurous gardeners and specialty market farmers. The interior of this melon is fragrant and floral, with creamy orange flesh that puts every other melon to shame. The fruits average one and a half to two pounds, with smooth, lightly striped skin. They thrive in a standard raised or in-ground garden bed with loamy soil and consistent moisture. You’ll know they’re ready to harvest when the skin turns from pale green to yellowish-tan. 

This is not a “slip” melon, so you’ll need to cut it from the vine rather than pulling. For maximum sweetness, wait until the melons fully ripen on the vine. The vines can continuously produce throughout the warm months as long as they have sufficient irrigation, drainage, and warmth. 

Northern growers, try out ‘Minnesota Midget,’ a delightful miniature musk melon developed by the University of Minnesota for short growing seasons. The compact plants are also better suited to containers because they don’t sprawl as widely as other melon varieties. 

The plants are disease-resistant and produce tasty miniature melons averaging about four inches in diameter. You can eat all the way to the rind and enjoy the ultra-sweet fruity, floral flavor. This cultivar is a “slip” variety, so it will naturally crack near the stem when it is time to harvest. If it is not easy to detach the fruit from the vine, leave it to ripen longer. 

Sweet Potatoes 

In spite of their name, sweet potatoes have no relation to regular potatoes. They are actually members of the Convolvulaceae (Morning Glory) family, while regular spuds belong to the Solanaceae (Nightshade) family. Sweet potatoes are dazzling vines that produce carbohydrate-rich edible tubers. The plants are so pretty that some folks grow them as ornamentals! If you are short on space, you can even grow sweet potatoes in containers with a trellis.

This warm-weather crop is native to subtropical and tropical areas of Latin America. In the U.S., most commercially grown sweet potatoes come from North Carolina, but you can grow them as annual vegetables anywhere as long as you have a minimum of 120 frost-free days. Zones 5-11 are fair game, but colder zones may struggle to cultivate them unless you have a greenhouse. 

Sweet potatoes are typically grown from “slips,” which are pre-sprouted pieces of stem that are planted like cuttings. You can order them online or purchase from a local nursery and plant as soon as they arrive. Ensure that the risk of frost has passed and the soil temperature is at least 60-65°F (16-18°C). If the nights are still cool, protect your baby sweet potatoes with a layer of row fabric. Gardeners in zones 5-6 may wish to wait until Late May or early June.

Planting Slips

Prepare six-inch deep furrows in compost-rich soil about 36-42 inches apart. Gently place each sweet potato slip in the furrow with the root end facing downwards, leaving 10-18 inches of space between plants. Backfill the furrow, ensuring that the upper inches of the slips (and any leaves) remain above the soil surface. Keep the plants consistently moist for at least two weeks. 

The slips are particularly fragile as they get established and need regular monitoring. Once the runners take off, the vines are very vigorous and should cover the beds, out competing weeds, and neighboring plants. Be sure your sweet potatoes have plenty of space to ramble! 

Heirloom Tomatoes

What is a summer garden without tomatoes? May is the best time to plant this iconic vegetable, which is technically a fruit. Botanically, tomatoes are fruits that form from a flower and contain lots of seeds, but they are culinarily used as vegetables, so they still fall into that category. All classification complications aside, tomatoes are warm-weather crops that you absolutely need to get in the ground by May!

From ultra sweet ‘Sun Gold’ cherry tomatoes to rainbow-hued ‘Brandywine Blend,’ 

You can even grow striped varieties like ‘Chocolate Sprinkles’ or ‘Green Zebra!’ Whatever you choose, ensure that the risk of frost has passed and your soil is sufficiently amended with compost. Tomatoes are a crop that deserves prime real estate in your garden. They will yield all summer long and require plenty of rich, loamy, well-drained soil to perform their best. 

Seeding and Transplanting

Most temperate gardeners start tomatoes indoors throughout the spring. If you forgot to start seeds indoors, don’t worry! You can still direct sow tomatoes in May or purchase established seedlings from a local nursery. Be sure that the tomato plants are not rootbound or leggy (with spindly weak stems). It’s best to avoid plants that are already flowering in their containers. If there are a few blossoms, remove them before transplanting so the tomato can focus its energy on forming strong roots and leaves.

When transplanting, it’s also advantageous to remove a few sets of the lower leaves so you can bury the stem deeper in the soil. Tomatoes, particularly heirlooms, are known for their ability to form adventitious roots. This is just a fancy term for the little bristles and roots that form along the stems. The roots that form along their stems dig deep in the soil for extra strong and wide root systems, enhancing water uptake, nutrient absorption, and overall crop performance. Be sure to leave a couple of sets of upper leaves exposed above the soil surface.

In addition to burying your tomato seedlings deep, you should install your trellis at the time of planting. Whether you’re using a tomato cage, chicken wire fencing, or a DIY tomato trellis, it is important to put the trellis in place at the same time as the baby tomato. It will be much easier to trellis and train the plant upward as it grows without damaging the roots or stems. 

Spicy or Sweet Peppers

Whether you like them spicy or sweet, almost all peppers are grown in a similar way. These warm-weather vegetables appreciate the sunny, frost-free days of May to anchor their roots and develop an abundance of leaves to fuel pepper production all summer long. Peppers are frost-tender crops that shouldn’t be moved outside until the soil is at least 75°F (24°C) and all risk of frost has passed. In northern zones, it’s often best to wait until one to two weeks after your expected last frost date to safely plant peppers outdoors. You can also use low tunnels or row cover to get the plants in the ground sooner.

Like tomatoes, these plants do best with a head start. These plants grow quite slowly and can take 80-100 days to ripen. If you forgot to start pepper seeds this spring, you can always source seedlings from a local farm, nursery, or fellow gardener. 

Because peppers take so long to mature, it’s important that May-transplanted seedlings are already fairly established. In areas with a long growing season (zones 8 and warmer), you can still seed peppers in May, but your harvests will be later than most.

Varieties

Colder zones may have trouble ripening larger pepper varieties like bell peppers due to the lack of heat days. If you don’t want a bunch of green bell peppers, consider growing a miniature variety or opting for a unique Japanese pepper like ‘Shishito.’ 

For a more exciting pepper experiment beyond the realm of supermarkets, try an Italian frying pepper like ‘Jimmy Nardello.’ Although they look similar to spicy chiles, these peppers are sweet, flavorful, and amazingly productive. Jimmy Nardellos are a classic heirloom brought by the youngest gardener of the Nardello family from Italy all the way back in 1887. Throw them on the grill or dry them for paprika and savor the rich flavor unmatched by any other pepper variety!

And for the spice lovers, you can’t forget to grow a nice crop of ‘Serrano,’ ‘Megatron’ jalapeno, or ‘Thai Hot’ chile peppers. Always wear gloves when handling these seeds! If you accidentally touch your eyes, you could spend the rest of the day crying rather than gardening.

Refreshing Cucumbers

Warm weather means it’s finally time for refreshing cucumbers. If you seed these vines in May, you’ll enjoy tender fruits by July. But if you give cucumbers a head start indoors in April, you can enjoy them sooner. 

These cucurbit-family vines are sensitive to transplanting but do well in a biodegradable pot or soil block that won’t disturb the roots. It’s very important to take extra care when planting cukes because their taproot will shrivel from the slightest disturbance. If you live in zones 7 or warmer, I highly recommend directly seeding the plants, as they will develop stronger root zones and won’t face transplant shock.

You may be surprised by the incredible diversity of cucumbers available to a gardener. Our favorites include:

Planting and Trellising

Cucumbers are frost-sensitive and require soil temperatures of at least 60-70°F (16-21°C). Northern growers should wait one to two weeks after their last frost date to seed outside. Cucumber seeds do best when planted at just ½ to ¾ inches deep and covered with a layer of row fabric to keep them warm and moist. Be sure to thin the plants and provide a trellis to keep the fruits off the ground.

While cucumbers can be grown with a tomato cage or raised bed, I find they do best with stakes or netting to wind upward. An A-frame trellis with pieces of twine works excellently to let the vines skyrocket and keep the fruit out of the dirt. Trellising is particularly important for humid areas where cucumbers commonly get powdery mildew or downy mildew diseases. Sufficient airflow between plants is crucial, and you can also choose disease-resistant varieties like ‘Tasty Green’ to keep fungal infections out of the garden.

Rambling Ground Cherries

Add a tropical twist to your May garden with ‘Pineapple Ground Cherry.’ These tiny tomatillo cousins have a fragrant fruity punch that almost reminds me of pineapple! Ground cherries are a warm-weather classic perfect for planting in May to ensure an abundant harvest by late July and August. If you started ground cherries indoors four to six weeks ago, May transplanting will offer an even quicker reward.

These nightshade-family plants require soils of at least 60°F (16°C) to germinate, ideally closer to 80°F (27°C). The plants love warm weather and ramble wherever they’re allowed. I like to stake them to keep the vines contained. The little papery husks will start developing a few weeks after the first flowers appear.

You will know the fruit is ripe and ready to harvest when they fall to the ground. This is why they are called ground cherries! The husks will turn golden yellow and easily peel away to reveal a ½ inch tangy-sweet fruit inside. 

Fragrant Basil

The quintessential summer herb, basil adds so much more to the garden than pesto. This sun-loving crop is best planted in the warm weeks of May to ensure abundant harvests all summer long. Companion plant basil near your tomatoes or peppers to provide pest-deterrent benefits and beautiful, pollinator-attracting flowers.

Basil seeds are best started indoors in the spring, but if you forgot to sow them in advance, May is a great time to direct sow outside. Once the risk of frost has passed and the soil is at least 60°F (16°C), the tiny basil seeds will sprout readily as long as they aren’t sown too deep. Provide consistent moisture and ensure at least 8-12 inches of space between plants.

Whether you grow ‘Italian Genovese,’ ‘Tulsi Holy Basil,’ ‘Sweet Thai Basil,’ or a ‘Six Basil Blend,’ basil plants always benefit from pinching. Pinching the tips of the leaves prevents bolting and encourages the plants to grow bushier. It also makes harvesting and cooking extra easy because you don’t have to worry about excess stems. Begin pinching plants when they are 8-12 inches tall and continue for the duration of the summer. 

In southern areas with scorching heat, plant a bolt-resistant variety and provide basil with afternoon shade, such as the eastern side of a tomato planting. Basil is a heat-loving crop but it often goes to flower during the hottest months. The flowers are edible, fragrant, and excellent for beneficial insects. But if you want to prolong the leaf harvest, keep up with the pinching and consider growing several successions of basil by planting every few weeks. Provide consistent moisture, as basil plants do not like drought stress.

Prolific Zucchini

The crowd-favorite summer squash is eager to take off in the warm weather of May. Zucchini is one of the most prolific garden vegetables, yielding up to 10 pounds of squash per plant! They often produce so many fruits that you cannot keep up with harvesting, eating, and preserving them. If you plant in May, you will have abundant zucchini bread, “zoodles,” and squash sautés throughout June, July, and August. 

If you forgot to start indoors, May is prime time to direct sow this crop. Like their cucumber cousins, zucchini plants dislike root disturbance. I once did an experiment where I transplanted a zucchini plant at the same time as I direct sowed zucchini seeds. The directly sown seeds quickly caught up to the transplanted seedling even though they were technically several weeks “behind.” Transplant shock often slows the growth of cucurbit crops, so you might as well direct sow if the weather is warm enough. 

Zucchini is very cold-sensitive and shouldn’t be planted outdoors until nights are reliably above 50°F (10°C). These plants absolutely love the heat and appreciate a row cover during chilly nights. However, you must remove the row cover once the plants begin flowering a few weeks after planting. It is a common mistake to leave the row cover on, which deters pollinators. 

Bees must reach the flowers of zucchini to ensure a high yield of fruits. Plant white alyssum, borage, or marigolds in the vicinity to attract as many pollinators as possible! And don’t forget that zucchini blossoms are a delicacy. You can harvest the male flowers (that grow from a long stem) and stuff them with beans or meat for a delicious Latin-style meal. Leave the female flowers (with fattened bases) on the plant to develop into squash. 

‘Black Beauty’ is among the most popular heirlooms, known for its shiny, green, uniform fruits with deliciously tender flesh. Once the plants reach maturity, be sure to harvest zucchini every few days to maximize yields and prevent the fruits from growing oversized.

Winter Squash

In spite of its name, winter squash is actually grown throughout the warmest summer months. Pumpkins, butternut squash, patty pan, acorn squash, and delicata are different variations of winter squash that you can grow in the summer, harvest in the fall, and store throughout the winter. These vines are very frost-tender and need at least 100 days of frost-free weather. 

In the coldest northern zones, it’s best to start winter squash indoors. Everyone else should direct seed outside one to two weeks after your last frost date. Like their cucurbit cousins, winter squash crops dislike root disturbance and prefer to germinate in place. Check the soil temperature with a thermometer before seeding. Most winter squash varieties require soil temperatures of at least 70°F (21°C) to germinate.

These expansive vining plants require six to eight feet of space between rows to allow their vines and leaves to ramble. The plants are best grown on mounds of soil, which facilitate drainage and promote faster soil warming in the spring. Large-fruited squash like pumpkins and butternuts also require extensive amounts of water and nutrients. After all, they are growing giant fruits with thick skins. Be sure that the soil is well-amended with compost, fertilized with a slow-release organic fertilizer, and irrigated with drip lines or soaker hoses. It’s best to avoid overhead irrigation (ie. sprinklers) that can cause foliar diseases like powdery mildew on squash plants.

Mulch is the most important secret for success with these crops. Straw or shredded leaves are best because they suppress weeds, conserve moisture, and keep the squash elevated off the ground. This prevents rotting in the areas where the squash sit on the soil surface. 

Juicy Watermelon

Watermelon is a refreshing summer essential that you must plant in May if you want to enjoy juicy fruits by July. If you’re overwhelmed by the gigantic, flavorless watermelons at grocery stores, plant a mini-fruit variety that will yield more quickly and provide personal-sized melons for regular enjoyment. I especially love the easier cleanup in the kitchen. No more ant problems!

‘Sugar Baby’ is the sweetest, mid-sized variety that will still fit in your refrigerator. The fruits average 7-10 inches in diameter and 8-10 pounds. With just 80 days to maturity, this melon is best for northern growers with shorter seasons. The plant still needs plenty of space to ramble and should be planted in mounded rows four to six feet apart.

For something more unique, try an ultra-sweet yellow-flesh watermelon like ‘Mountain Sweet Yellow’. These giant oblong melons average 20-35 pounds and can feed an entire barbeque cookout. The yellow flesh is a conversation starter and particularly rich with complex flavor, unlike supermarket varieties. Long, warm summers are essential for these giant melons to properly ripen on the vine, so only plant this variety in southern areas.

Watermelons are more difficult to harvest than other crops because it is sometimes unclear if they are ripe. You want to ripen your melons on the vine for the sweetest, most flavorful fruits, but they don’t always give overt signs when they are ready. 

Thankfully, as a commercial vegetable farmer, I learned quite a few tricks to harvesting the best watermelons:

Vibrant Sunflowers

Summer sunflowers are crucial to a gorgeous pollinator-friendly garden. Better yet, these iconic sunshiney blooms provide ample seeds for roasting and eating in the fall. You may think all sunflowers are created equal, but there are actually two different categories:

• Single-Stalk: These are the classic ultra-tall plants that produce one giant flower per plant.
• Multi-Branching: These plants produce multiple stalks with lots of small to mid-sized flowers.

Fortunately, varieties in both categories can be grown about the same. Towering single-stalk varieties like ‘Mongolian Giant’ can be sown at the same time as multi-flowered ‘Lemon Queen’ or ‘Evening Sun’. The latter are better for a summer display that lasts all summer long, while the single-stemmed giants are best for harvesting seeds.

Sunflowers despise root disturbance from transplanting, so it’s best to wait one to two weeks after your average last frost date to direct sow them outdoors. If you must start inside, be sure to use biodegradable pots or soil blocks. Sow sunflower seeds ¼ to ½ inches deep with 12-24 inches of space between each plant. For a wall of giant sunflowers, ensure at least two square feet of space per plant to promote the biggest floral display.

Sunflowers don’t mind poor soil or prolonged droughts, but they do best with plenty of moisture in the beginning. Avoid planting tall varieties on the south end of your garden, or they may cast shadows over your treasured vegetable crops. Instead, keep sunflowers in full sun along the edges of the garden. In windy areas, they benefit from a fence or added support to prevent toppling.

Ultra Sweet Corn

A golden-yellow sweet summer classic, corn is among the best vegetables to plant in May. This heat-loving crop grows quickly and thrives in abundant sunshine. The seeds germinate rapidly and don’t require excessive care as long as the soil remains moist and above 65°F (18°C). 

It is a common misconception that you cannot transplant corn. In reality, corn performs excellently when transplanted! This vegetable is actually a member of the grass family (Poaceae). Grasses are known for their resilient roots, and corn is no exception. In colder climates, I like to sow corn a few weeks before the last frost date in small cell trays. Transplant outside one to two weeks after the risk of frost has passed and ensure 12-24 inches between plants. Zones 7 and warmer can easily direct seed corn in May.

Succession Planting

True corn lovers should succession sow this crop throughout the summer to ensure a continuous supply of sweet cobs for the grill. This means you can seed corn every 10-14 days from May through July, offering a consistent harvest for end-of-summer cookouts.

Sweet corn matures in around 60 to 80 days, but popcorn takes up to 110 days. For delectable classic roasted cobs, try ‘Buttergold’, or plant an heirloom rainbow variety like ‘Glass Gem’ for beautiful cornmeal and ornamental decor.

Remember that corn can cross-pollinate by wind, so you can’t plant a lot of varieties in the same place at once. Instead, plant separate varieties on opposite ends of the garden or stagger the plantings. If you sow one type of corn two weeks before the other, they will produce tassels at different times and likely avoid cross-pollination. But if a cross happens, you may end up with a super special variety unique to only your garden!

Heat-Loving Okra

One of the most heat-resilient crops in the garden, okra is a southern classic because it thrives in scorching summers. Northern growers don’t often grow this plant, but gardeners in zones 8-12 will appreciate the tenacious spirit of okra through even the hottest days. This plant can handle triple digits with ease, but it will struggle if temperatures dip below 60°F (16°C). If you wish to grow okra in zones 7 or colder, be sure to start indoors or wait two to three weeks after your last frost date to plant it in the ground.

Okra is a hollyhock relative ideal for incorporating in crop rotations because it’s not related to other garden vegetables. The edible flowers are just as delicious as the long okra pods. If you seed okra in May, you can enjoy your first harvests by July. If the spines intimidate you, try out ‘Clemson Spineless’ for a delicious yield without the pain and preparation. 

Snappy Green Beans

Green bean casserole isn’t only an autumn tradition! Garden-fresh green beans can be used on the grill, in salads, and as a delicious side dish all summer long. Whether you call them snap beans, string beans, or green beans, they are all the same.

This warm-weather vegetable is best planted in May, with several successions to provide continuous yields of immature pods. Many growers plant green beans every two weeks so that, as one round of plants exhausts itself, a new generation is ready to take over. Green beans are harvested green because the seeds inside have yet to mature. This ensures a satisfying snappy crunch without the need to boil them like shelling beans. The whole pod is edible and easy to harvest in big handfuls from the plants.

You can directly sow green beans outside one to two weeks after your average last frost. The soil must be at least 65-70°F (18-21°C) for adequate germination. In areas with super hot summers, avoid planting beans in late May or onward, as temperatures above 90°F (32°C) prevent beans from forming. Fortunately, well-watered bean plants can often withstand the heat but won’t produce during the hottest months. As the weather cools, they can start yielding beans again.

The bushy plants can be spaced 4-6 inches apart in rows 24 inches apart. Sow seeds about 1 inch deep and keep consistently moist until they emerge in 6-12 days. Pole beans require a trellis, but upright bush varieties like ‘Jade’ can stand up on their own. 

Interestingly, green beans are not always green! Yellow and purple varieties add a unique twist to this classic. Try ‘Trio Bush Beans’ for a colorful burst in the garden. 

Japanese Eggplant

After trying Japanese or Thai eggplants like ‘Long Purple’, I no longer feel the need to grow Italian ones! These eggplants are delicately flavorful and less spongy, offering a delightful texture to sauces, roasts, and purees. Additionally, they have very few seeds, and the skins are thin and easy to cook, so you don’t have to worry about peeling. The heat-loving plants reliably produce all summer long, and regular harvests encourage more and more fruits!

Seed-elongated eggplants outside two to four weeks after your last frost when the soil is at least 70°F (21°C). These heat-loving plants refuse to germinate in cold soil or areas where nights still dip into the 40s and 50s. Gardeners in zones 3-6 may want to wait until June, but zones 7 and warmer can reliably direct sow this crop in May. The mid-maturity plants also benefit from a head start indoors 10-12 weeks before your average last frost in short-season areas.

Eggplants need at least 18 inches of space between plants and protection from cold weather. I like to start the plants under row cover and remove the fabric once they begin flowering. They are very frost-sensitive and struggle in cold climates without protection. You’ll know your eggplants are ready to harvest when the fruits are glossy deep purple, and about 8-10 inches long.