9 Fruits and Vegetables to Direct Seed in May
Are you looking to direct seed some fruits or veggies into your garden in the midst of spring? It's the perfect month to direct sow a number of different seeds right into your garden plot or raised beds. In this article, gardening expert and former organic farmer Logan Hailey shares her favorite fruits and vegetables to start direct seeding into your garden during the month of May.
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With summer just around the corner, May is the prime time to direct sow frost-sensitive crops and transplant all your warm-weather veggies into the garden. This month, southern gardeners must prioritize heat-tolerant crops, while northern gardeners finally have the freedom to plant anything under the sun!
So which vegetables should you grow? There are many different choices to pick from, depending on your hardiness zone and local microclimates.
Let’s dig into the top 9 veggies to plant in May, depending on your garden goals this season!
Corn
- Soil Temperature: 75-90°F
- Seeding Rate: Sow ¾ to 1” deep, 6-7” apart, in rows 24-36” apart.
- Direct Seed in These Zones: Zones 5-12
- Transplant in These Zones: Zones 1-4
When you are sure your last spring frost date has passed, corn is ready to go in the ground! This grass-family vegetable thrives in warm weather and long days. It requires a minimum soil temperature of 65°F and does best when seeded straight into the soil.
The large kernels are easy to handle and make a fun project when gardening with kids. You can harvest fresh ears of sweet corn as early as July!
Some far northern growers transplant corn from cell trays in mid-May to enjoy an earlier harvest. They use black plastic mulch or landscape fabric to warm the soil in advance. However, this is only recommended for true sweet corn fanatics who can’t wait to savor this popular summer veggie.
Don’t waste your valuable raised bed areas for this space-hogging crop. Instead, plant corn in a large sunny patch of ground with lots of compost. Be sure that the 6 to 7-foot tall plants won’t shade out any of your other veggies.
If you want to enjoy sweet corn all summer long, make successive plantings every 12 days. This allows you to experiment with different varieties because the staggered plantings ensure that they won’t cross-pollinate. For best results, keep sweet corn and popcorn separated by both time and space. A minimum of 12 days and 25 feet between plantings will prevent cross-pollination.
Watermelon
- Soil Temperature: 80-90°F
- Seeding Rate: Sow ½ to 1” deep, 3 seeds every 18-36”, in rows 6-8’ apart, then thin to 1 plant every 2-3’ feet. Leave plenty of space for vines to ramble.
- Direct Seed in These Zones: Zones 6-12
- Transplant in These Zones: Zones 1-5
Nothing says summer like a juicy sweet watermelon. Plant a mini-fruiting variety in early May if you want to eat watermelon by July. Some personal-sized melons like ‘Sugar Baby’ and ‘Cracker Jack’ mature in as little as 70 days, while standard large watermelons can take up to 90 days from seed to harvest.
Variety selection is incredibly important with melons. Watermelons come in red, yellow, pink, and orange flesh varieties. There are two main types of watermelon seeds:
Diploid
These are the classic watermelons you probably grew up with. They aren’t quite as finicky as seedless types and are more likely to thrive in a beginner garden. Standard seeded watermelons are open-pollinated and/or heirloom varieties that have large black and white seeds inside.
Contrary to popular belief, the black seeds are edible and nutritious. They won’t cause a watermelon to grow inside your stomach like you were told as a child. You can also save the seeds to replant next year.
Triploid
Seedless watermelons offer all the flavor and smooth texture of melons without the interruption of seeds. They are slightly harder to grow because seeds need very specific moisture and temperature conditions to germinate properly. These hybridized types need a pollinator watermelon nearby to ensure proper fruit set.
Neither types of watermelon are GMO; however, triploid watermelons have been specially bred to be seedless. This means you won’t be able to save seeds or replant from your initial sowing. You’ll have to buy seeds next year or grow an heirloom diploid variety.
Direct sow watermelons 1-2 weeks after the last frost when the weather is warm, settled, and completely frost-free. Supply continuous moisture and never let these seeds dry out.
If you must transplant, sow indoors no sooner than one month before planting. Be very careful when transplanting, as the seedlings are very vulnerable to root disruption.
Cantaloupe
- Soil Temperature: 70-90°F
- Seeding Rate: Sow ½” deep at a rate of 3 seeds per 18” in rows 6’ apart. Thin to 1 plant every 18” and leave plenty of space for vines to stretch out.
- Direct Seed in These Zones: Zones 5-12, Zones 4 and colder should wait until June
- Transplant in These Zones: Not recommended
Long sunny days and frost-free weather mean that tender cantaloupes can finally germinate in your garden. Like most Cucurbit-family crops (cucumbers, squash, pumpkins, etc.), melons are best direct-sown. They are very sensitive to transplanting and thrive best in the warm soils of late May.
Also known as musk melons, these specialty sweet melons make a grocery-store cantaloupe taste like cardboard, comparatively. You can plant French, Egyptian, or American melon varieties and expect delicious fruits by late June or early July.
Wait 1-2 weeks until after your last frost date to get cantaloupe in the ground. Like watermelons, they demand continuous moisture and consistently warm conditions. Protect melon seedlings from cool nights using a low tunnel or row cover. However, you will need to remove the row fabric when the plants start flowering to ensure adequate germination.
Okra
- Soil Temperature: 75-90°F
- Seeding Rate: Sow seeds ½” deep about 4-6” apart. When true leaves appear, thin to 12-18” between plants.
- Direct Seed in These Zones: Zones 8-12
- Transplant in These Zones: Zones 2-7
Okra is a southern classic that is related to cotton and poppymallow. This unique vegetable is great for crop rotations because it doesn’t have many garden relatives.
Okra plants are incredibly heat-tolerant and don’t mind the intense sunshine of southern summers. In fact, okra prefers hot weather that is consistently above 65°F. Nighttime temperatures below 50°F may harm the crop.
Okra can be direct sown 2-3 weeks after the last frost date. The plant takes 50-60 days to start fruiting. In northern areas, you will want to start okra indoors and transplant out around the same time as you plant peppers and tomatoes.
The okra fruit looks like elongated pods with a sweet, juicy, earthy flavor that tastes excellent in dishes with zucchini or summer squash. The flowers are also edible and delicious when stuffed or deep-fried.
Beans
- Soil Temperature: 75-90°F
- Seeding Rate: Plant bean seeds 1” deep about 3” apart in rows 2-4’ apart.
- Direct Seed in These Zones: Zones 5-10
- Transplant in These Zones: Zones 1-4
Green beans scream summer! You can start early snap beans in May and plant another succession in July or August for autumn harvests.
Whether you choose pole beans or bush beans, these vigorous nitrogen-fixing plants provide continuous harvests as long as the weather is warm. Pick beans as soon as they are mature (the size and shape depend on variety) to encourage more pod production.
As soon as the danger of frost has passed, direct sow bean seeds in loamy, well-drained soil. Soil temperatures above 70°F are needed for proper bean germination. Plants thrive in air temperatures around 65 to 85°F and enjoy row cover to protect them from cold nights.
If you plan to trellis beans, install the trellis first and ensure it is located on the north-facing side of your garden beds. You don’t want rambling beans to shade out your other crops!
Zucchini
- Soil Temperature: 75-95°F
- Seeding Rate: Sow ½ to 1” deep, 18-24” apart, in rows 4-6’ apart. Leave space to walk between the large plants. If transplanting, start just 1-2 weeks before planting. Seedlings mature quickly. Grow in 4” pots and do not allow to get root bound.
- Direct Seed in These Zones: Zones 6-12
- Transplant in These Zones: Zones 1-5
Did you know that a single zucchini plant can yield up to 10 pounds of squash? These prolific vegetables are large, broad-leaved, and ready to outcompete any weeds that try to spring up. Zucchini only demands consistently warm weather, full sunlight, and adequate moisture.
Zucchini is extremely cold-sensitive and prefers to grow at 60 to 85°F. For zone 6 and warmer gardeners, this summer classic is eager to spring up in mid to late May’s warm soils. Direct sowing is ideal, but northern gardeners may wish to start zucchini indoors around the last frost date and plant out 1-2 weeks later.
Buffer your zucchini against chilly nights by covering it with fabric row covers. Like melons, you’ll only want to keep the covers on until the plants begin to flower.
The most common mistake beginners make with zucchini is forgetting to attract pollinators to the area. Interplant with white alyssum, marigolds, and borage.
For the quickest harvest, plant an early variety like ‘Dunja’ or ‘Green Machine.’ You should be able to make “zoodles,” zucchini pizza, or zucchini pancakes by mid-June.
Sweet Potatoes
- Soil Temperature: Minimum 60°F
- Seeding Rate: Plant slips 3-4” deep, 10-18” apart in rows 36-60” apart.
- Direct Plant Slips in These Zones: Zones 8-12
- Transplant in These Zones: N/A
Sweet potato is a unique crop that isn’t actually related to potatoes. Rather than growing from seed, these vibrant roots are started from sweet potato slips. Like bare-root strawberry crowns, these rooted sprouts are harvested from a mature plant and shipped to your home.
You can order sweet potato slips from seed companies in the spring or purchase them from a local garden store. May is too late to start your own slips, but you can plan to do that next year about 6 weeks before your last frost date.
Plant sweet potatoes when the weather has thoroughly warmed, and there is no chance of frost. If the slips appear wilted or dry, don’t panic. Rehydrate the slips by wrapping a moist towel over the roots. If planting is delayed by a week or more, tuck the slips into a moist sterile potting mix and keep them indoors until your beds are ready.
Sweet potatoes thrive in rich, well-drained soil mounded in hills like potatoes. Raised beds with sandy loam are ideal. Provide plenty of water until the slips are established (roughly two weeks).
Once the plants take off, they are remarkably heat-tolerant and somewhat drought resilient. You can also enjoy the sweet potato leaves as a substitute for salad greens in peak summer.
Potatoes
- Soil Temperature: 60-80°F
- Seeding Rate: Plant tuber pieces 2-3” deep (eye up if possible), 12” apart, in rows 30-36” apart. When plants reach 6-8” tall, mound soil to create a hill. Repeat the hilling process as the plants grow until each mound is about 12” tall.
- Direct Plant in These Zones: Zones 3-9
- Transplant in These Zones: N/A
As members of the Solanaceae (nightshade family), potatoes prefer many of the same planting conditions as their tomato and pepper cousins.
However, they are more tolerant of cool springs and can be planted throughout mid-spring. May is a great time for northern growers to get midseason and late potatoes into the ground. Southern growers ideally plant potatoes in March or April.
When picking a variety, it’s important to note that there are three main types of potatoes:
Early
Early spuds have the quickest days to maturity, ranging from 60-80 days to harvest. If you harvest them young, they are considered “new” potatoes. New potatoes have the most tender skins and soft flesh but don’t store very long.
Midseason
In the 80-110 days to maturity range are popular varieties like ‘Yukon Gold,’ ‘French Fingerling,’ and ‘Gold Rush.’ These types tend to have tender flesh and smooth skins with moderate storage capacity when cured.
Late
Long-season potatoes like ‘Russet’ take up to 130 days to mature. They tend to be the best storage variety. These plants produce the largest spuds with thick skins for winter soups, stews, and baking.
You don’t have to worry about cross-pollination with potatoes, so feel free to experiment with as many varieties as you’d like.
Remember, seed potatoes aren’t true seeds; they’re technically small tubers. Each tuber has multiple “eyes” (root buds) on it. You can plant seed potatoes as whole pieces or cut them into chunks. Just be sure that every chunk has at least one “eye.”
Basil
- Soil Temperature: 65-70°F
- Seeding Rate: Sow seeds ¼” deep at a rate of 2-3 seeds per inch in rows 12-18” apart. Thin plants to 4-8” apart.
- Direct Seed in These Zones: Zones 8-12
- Transplant in These Zones: Zones 1-7
Basil is the quintessential summer herb that will provide abundant harvests from May until frost. Basil grows best in rich loamy soil, full sunlight, and warm temperatures around 60-80°F.
Whether you opt for Italian basil, Thai basil, Holy Tulsi (Indian), basil, or purple basil, you can confidently sow basil seeds outdoors as soon as the chance of frost has passed.
Basil seeds take just 5-10 days to germinate and prefer soil temperatures above 60°F. Use a soil probe to check your garden beds before seeding.
If you started basil plants indoors last month, this is also the perfect time to transplant. Maximize your success by covering newly transplanted seedlings with a light layer of row cover. As soon as plants reach 8-12” tall, begin pinching the leaf tips to prevent bolting and encourage bushier growth.
While basil is heat-tolerant, it can be damaged by drought stress during warm weather. Keep your basil thoroughly hydrated all season long. If you have problems with bolting basil, sow several successions of basil seeds every couple of weeks. You can also use the edible flowers as a garnish or leave them for pollinators to enjoy.
Final Thoughts
For most gardeners, May is the “safe zone” when you can comfortably seed any frost-tolerant crops directly into your garden. In hot climates, you should avoid planting any more cold-weather crops like lettuce, peas, or salad greens that may bolt or wilt in the summer sun.
May is also the perfect time to maximize your companion planting. Don’t forget to add lots of flowers and herbs to the corners of your veggie beds! You can even sow a “Three Sisters” planting of corn, beans, and squash.
