Collards

Collards are a great crop to grow in Virginia – or anywhere, really. They’re cold- and heat-tolerant, nutritious, quick-growing – 75 days from seed to maturity – and most importantly, tasty. Collards were bred from wild cabbages in the eastern Mediterranean region, where Greeks and Romans feasted on them in ancient times. Enslaved Africans introduced collards to the Americas, growing them for their own consumption in Latin America and the antebellum South. The taste for collards spread across the United States in the mid-20^th century Great Migration, as African-Americans fled Jim Crow and found industrial jobs in northern cities. Today, collards are a staple food in southern and eastern Europe, Kashmir, east and west Africa, Brazil, and all over the United States.

Varieties

Collards are the same species as cabbage, Brassica oleracea. Collards belong to the “Acephela” group, i.e. “headless,” within B. oleracea. By contrast, traditional cabbages belong to the “Capitata” group.

North Carolina State suggests a few collard varieties that do well in home gardens:

• Blue Max: Compact and vigorous
• Butter: Cabbage-like leaves
• Champion: Resistant to bolting in hot weather
• Georgia Southern: Heirloom variety. Good heat and cold resistance.
• Morris Heading: Another heirloom, also called Carolina Heading. Dark green leaves and cabbage-like flavor.
• Top Bunch: Early harvest.
• Vates: Blue-green, slightly savoyed (wrinkled) leaves

Seed catalogs and heirloom seed collectors have detailed information about the characteristics of specific collard varieties, including cold tolerance – some varieties are hardy to 0℉ – and bolt resistance in hot weather, size, flavor, thickness of leaves, and time to maturity.

Bed prep

Collards grow well in many soil types, from sandy coastal soil to heavy Piedmont clay. For best results, amend your soil with plenty of organic matter. When starting new garden beds, dig 4 inches of compost into the top 12 inches of soil. For established beds, spread 2 inches of compost and work it gently into the soil with a rake or broadfork. We recommend no-till methods to preserve soil structure and reduce erosion and compaction.

As a leafy green, collards also benefit from added nitrogen. Oklahoma State University (OSU) recommends adding 70 lb. nitrogen per acre before planting. This translates to 6 oz. urea (46-0-0) or 21 oz. blood meal (roughly 12-0-0) per 100 square feet. OSU then recommends side-dressing three weeks after emergence (or transplanting) with 4 oz. urea or 15 oz. blood meal per 100 square feet.

Finally, collards grow best near neutral soil pH, 6.0 to 8.0. A soil test will measure pH and tell you how to make any needed adjustments. A soil test will also measure nutrients like potassium and phosphorus and recommend appropriate amendments. Our Horticultural Help Desks can help interpret the recommendations that come with soil test results.

Starting

Collards perform well when seeded directly into the garden, as well as when started indoors and transplanted to outdoor settings later.

Indoors This is the best option for a spring crop, since seeds germinate slowly in cold soil and might rot before germinating. Aim to transplant at the average date of last frost. In Charlottesville, which is now in USDA hardiness zone 7b, this is between April 5^th and 15^th. Start seeds 4-6 weeks before transplanting. Harden seedlings off by placing them outdoors for increasing amounts of time, starting about a week before planting.

Outdoors This is a good option for a fall crop planted in late summer. Consult the Virginia Cooperative Extension’s Home Garden Planting Guide for recommended planting dates in your hardiness zone. Charlottesville is now in zone 7b. (The map in that document has not been updated, but the planting dates for the various hardiness zones are unchanged.)

Before seeding, rake the bed well to ensure good seed-soil contact. Plant seeds ¼ to ½ inch deep, 2 inches apart in rows 18 to 30 inches apart. Water well and keep the soil moist, particularly in hot weather. After seedlings are established, thin them to 12 inches apart for full-size plants, or 4 inches for “baby” plants that can be eaten raw.

Cultivation

Collards are heavy feeders. Side-dress with nitrogen to ensure big, green leaves. As mentioned above, OSU suggests adding 4 oz. urea or 15 oz. blood meal per 100 square feet three weeks after emergence or transplanting.

Collards require fairly moist soil; otherwise, they will become bitter. Aim to keep the top 6 inches of soil moist. They need about 1 inch of water per week, whether from rain or irrigation, but the exact amount will depend on local temperature and soil type. Mulch plants with grass clippings or weed-free straw to conserve soil moisture.

Collards are cold-tolerant, and with a little protection can stay alive all winter. For more information about row covers – which provide protection from temperature and wind – check out Piedmont Master Gardener Ralph Morini’s article.

Pests and diseases

Pests

• Caterpillars (sometimes called “worms”) are moth or butterfly larvae that infest collard leaves: diamondback moths, cabbage loopers, various cabbageworms, armyworms, and cabbage webworms. They damage collards by chewing on leaves. The damage can range from a few small holes to complete skeletonization.
• Aphids feed on collards by piercing the waxy cuticle coating the leaves, then sucking sap from the plant. Aphids reproduce very quickly, and serious infestations can appear seemingly overnight. Their damage appears as wilted and deformed leaves and stems.
• Whiteflies, like aphids, feed by piercing and sucking. They are notorious for spreading plant viruses, so the first sign of an infestation might be a viral disease (see below).
• Harlequin bugs are similar in form to stinkbugs, but they’re reddish orange with black markings. They are also piercing/sucking feeders. Their damage appears as white patches on leaves.

Prevention is the best way to avoid insect damage. Clean up all weeds and plant debris at the end of the growing season to deny insects a place to spend the winter. Rotate crops to keep plants away from any pests that do manage to over-winter. This is surprisingly effective even in a small garden! Examine your plants often, particularly on the undersides of leaves, to look for eggs, larvae, and adult insects. Lightweight row covers can keep insects away from plants – but they can also provide a safe habitat where pests can thrive.

It might be necessary to treat severe infestations with chemical insecticides, but this should be a last resort. For more information about insecticides, including organic options, consult the Virginia Cooperative Extension’s Pest Management Guide. Always follow the instructions on the label and use personal protective gear like gloves and eye protection. Also take great care to avoid harming pollinators: don’t spray flowering plants, and spray in the evening when bees are less likely to be present.

Diseases

• Damping-off is caused by Pythium mold. Seeds and seedlings rot and either fail to germinate or decay shortly after germination. Avoid by not planting in cold, poorly drained soil. Before starting seeds indoors, thoroughly wash all pots, trays, and tools with hot soapy water. Always use potting or seed-starting mix, never soil, to start seeds.
• Downy mildew occurs in humid environments. The lower surface of leaves develops a gray, fuzzy film, then the upper surface turns brown and dies. The best way to avoid downy mildew is to keep leaves dry. Space plants appropriately, as described above, to allow air movement. When irrigating, direct water towards the base of plants, not the leaves.
• Alternaria leaf spot causes dry brown spots with concentric rings on leaves. Eventually, leaves turn yellow and die. Alternaria fungi are soil-borne, so avoid splashing soil onto leaves when irrigating. Mulch helps prevent soil splashing. Crop rotation can deny the fungus a host. Alternaria grow well in hot, humid environments, so keep leaves dry as described above.
• Black rot is a bacterial disease. Yellow, triangular regions appear at the edges of leaves, then grow until the entire leaf is affected. Prevention is critical because no known chemical can control black rot. Keep leaves dry, rotate crops, and clean up plant debris, especially from infected plants.
• Viruses are usually spread by insects. There are no antiviral drugs for plants, so prevent viral diseases by controlling insect infestations as described above. Viral infections cause leaves to appear patchy, mottled (see picture), and distorted. Some weeds are hosts for viruses, so weed control can also help with prevention.

It’s almost impossible to cure plants of severe disease; if plants are infected, remove then immediately. Dispose by burying or burning, not composting. It might be possible to use chemical treatments to prevent diseases from spreading to nearby plants. Consult the Pest Management Guide for details. Proper diagnosis is essential to choosing the right preventative treatment.

Heirloom Collard Project

Collards are a worldwide crop, but they have a prominent place in American culture because of their historical connection to Black agricultural and culinary history. The Heirloom Collard Project, founded by famed Virginia gardener and educator Ira Wallace, aims to increase awareness of the history of collards in two ways: first, by sharing stories of collards’ importance to American culture, and second, by sharing of historical collard varieties, in a collaboration with the Seed Savers Exchange. The project is always looking for new growers to produce more seeds of in-demand varieties, so if you like saving seeds and are interested in American food history, considering getting involved!

References and further reading

featured image: Pexels.com

Black Foodways and Cuisine National Museum of African American History and Culture

Brassica oleracea (Collards Group) North Carolina State Extension

Cabbage, Broccoli, and Other Cole Crop Diseases Clemson Cooperative Extension

Cabbage, Broccoli, and Other Cole Crop Insect Pests Clemson Cooperative Extension

Collard Greens North Carolina State Extension

Cool Season Greens Production Oklahoma State University Extension

Growing Collards and Kale in Home Gardens University of Minnesota Extension

How to Grow Kale and Collards Michigan State University Extension

Pest Management Guide – Home Grounds and Animals Virginia Cooperative Extension

Virginia’s Home Garden Vegetable Planting Guide Virginia Cooperative Extension