When to plant collard greens from seeds or transplants (2024)

Knowing when to plant collard greens is key to their success. They can be grown directly from seeds or the seedlings transplanted into garden beds or containers to get a head start on the harvest. When deciding how and when to plant collard greens, your local climate and the length of your growing season are some of the most important factors to consider. In this article you’ll learn about the importance of timing, when to start collard green seeds indoors, when to direct sow outdoors, when to transplant seedlings, and get tips for growing healthy plants.

Types of collard greens

Flip through any seed catalog and you’ll see that there are different types of collards available. It’s best to select varieties that thrive in your region. Some of the most popular varieties include:

Champion

Days to maturity: 70 to 80
U.S. Hardiness Zones: 3 through 12
Grows two to three feet tall

Georgia

Days to maturity: 65 to 75
U.S. Hardiness Zones: 3 through 10
Grows two to three feet tall with one-foot spread

Georgia southern

Days to maturity: 50 to 70 days
Can withstand winter temperatures down to about 20 degrees F (-6 degrees C.)
Well-suited for container gardening

Green Flash

All about collard greens

One of the Brassicas or cole crops, collard greens are extremely nutritious akin to kale, cabbage, and broccoli. Collards are high in fiber and essential nutrients and low in cholesterol. Although usually grown as annuals, this cool season vegetable is technically a biennial. That means it won’t flower or set seed until its second year—provided it doesn’t succumb to a killing frost.

When still young, the tender leaves can be eaten raw in salads. But, as collard plants mature, a single dark green leaf can grow to be a foot long or more. These large leaves are typically cooked down with garlic and hot pepper or added to soups or stews with other vegetables.

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Why good timing is important

Contemplating when to plant collard greens? Although they can withstand some hot weather, collard greens prefer cooler temperatures—and, as it happens, cooler weather can even improve the flavor of your harvest.So, what if your springtime seedlings are still very small by the time summer really heats up? Or maybe a fall frost snuffs out your collards before they were big enough to harvest? In both cases, you’d be out of luck. But get the timing right and you could come away with extra tasty spring, autumn, andwinter harvests.

When to plant collard greens from seed indoors

You don’t want to get stuck with leggy, unhealthy seedlings, but you also don’t want to wait so long that you lose any advantage you might have gained from starting plants indoors early. So, how do you know just when to plant collard greens from seed? On average, collard green seeds take 5 to 10 days to sprout. For early spring gardens, start seeds indoors 5 to 7 weeks before you plan to set them out. Plant seedlings out in spring once the soil can be worked and danger of a hard frost has passed. Mature collards are tough and can handle light frosts, but in the seedling stage they’re less robust.

As for fall and winter greens, the object is to make sure your seedlings mature before a prolonged, killing frost sets in. I therefore start seeds inside in early summer, transplanting them to garden beds 5 to 6 weeks later.

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How to start collard seeds inside

So, you’ve decided when to plant collard greens, but do you know how to best start your seeds inside? It’s important to sow seeds in a well-draining seed-starting mix. Plant a quarter inch deep and one inch apart, or two seeds per cell if planting in plug trays or cell pack flats. Because your seeds will germinate more quickly and more uniformly if the growing medium is between 70 to 75 degrees F (21 to 24 degrees C), you might also want to use a seedling heat mat. Once the seeds sprout, thin to one plant per cell and remove the heat mat.

When to plant collard greens from seed outdoors

Generally speaking, you can direct sow seeds in garden beds outdoors in early to mid-summer for an October or November harvest. And, if you happen to live in a very warm climate, direct sowing seeds in late summer and again in the fall will net you winter and spring crops, respectively.

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How to plant collard seeds directly into the garden

Direct sow seeds in light, rich garden soil that is kept moist but not waterlogged. Seeds should be placed at a depth of about a quarter inch and spaced 6 to 12 inches apart. For full-sized plants, eventually thin the seedlings 18 to 24 inches apart (eat the thinnings). Ultimately, your plant spacing will depend on the mature size of the variety you choose and whether you intend to harvest mostly fully grown leaves or more tender “baby” greens.

When to plant collard greens from transplants

Knowing just when to plant collard greens from transplants depends on your local climate and growing conditions. Here’s a quick breakdown for you:

When to plant collard greens in southern areas (warmer climates)—Although you can plant transplants in spring, summer, and fall, you’ll likely have best results with those you plant in very early spring and those you plant in the fall. Despite collard greens’ reputation for heat-tolerance, too much heat can still drive them to bolt.
When to plant collard greens in northern areas (cooler climates)—Plant collards from transplants 2 to 3 weeks before your last average frost date. If you have an early maturing variety, you might also try transplanting collards in the garden in mid-summer for an additional late season harvest.

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How to plant collard transplants

When mature, collard greens can grow up to three feet tall and they may have anywhere from a one- to three-foot spread, depending on plant variety. Keep this in mind as you space your transplants. Good air flow improves plant health and reduces the risk of common diseases. Position individual transplants every 18 to 24 inches and then provide at least two feet in between plant rows.

Care and maintenance of the plants

Food and Water—Your collards will thrive in soil that’s rich in organic matter and nitrogen with a soil pH of between 6.0 and 6.5. Periodically apply a slow-release, organic fertilizer as needed and make sure plants get at least an inch of water weekly. When watering, avoid wetting plant leaves to help prevent bacterial diseases like black rot.
Cover-up—Mulching around collards will help to lock in moisture, insulate roots, and suppress weeds.
Monitor for insects—Aphids, cabbage loopers, flea beetles, cut worms, and other pests can make a quick meal of your collard greens. Protect plants with floating row cover and routinely check for signs of insect activity. You may be able to remove small, localized infestations by hand, but, for more widespread problems, you may wish to try an organic, soap-based insectide or a microbial agent like Bacillus thuringiensis or Bt.

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Harvesting collard greens

To harvest, you can snip a few of the bottom leaves from each plant while they’re still tender and small or you can wait until individual plants are mature (or nearly so) and then cut these down to their crowns. I use garden snips to make a clean cut. Rinse leaves, pat dry, and store for up to a week in a plastic bag in the refrigerator. Alternatively, you can blanch and freeze your crop, the same way you would freeze kale.

Southern comfort food

Now that you know when to plant collard greens—whether from seeds or transplants—and how to best care for your plants, you’ll be ready to reap multiple harvests of this traditional Southern green. As with kale, you can toss tender young collard greens with lettuce and tomatoes or cook and serve bunches of the larger leaves on their own.

How you intend to harvest your collards, as well as when and how often you’ll harvest them, all influence the distance you leave in between individual plants and rows. Cut-and-come again growers can afford to pack plants in more tightly. On the other hand, if you want to cut the top bunch of fully mature leaves from each of your plants, you must give them a wider berth.

Remember, these cool-season veggies generally do best when grown in the spring and early fall, but they can withstand some hot weather, too. If you choose a variety that’s well-suited to the length of your growing season and your climate, you can enjoy at least one—and usually two—crops per year.

For more information on growing hardy greens, be sure to read these articles:

How to plant and grow kale
A cabbage growing guide
When and how to harvest cabbage
When to harvest spinach from your garden