Collard Greens in Zone 6B — Southeast

Collard greens are a staple in the South, and for good reason. Their slightly bitter, earthy flavor is delicious braised, sautéed, or even added to soups. Plus, they thrive in our long summer growing season, giving you a steady supply of nutritious greens from early summer well into the fall.

Our hot and humid summers can present some challenges, like increased disease pressure and pests. But with a little planning and attention, you can easily grow a bumper crop of collards. The long 208-day growing season here gives you plenty of time to get it right.

Starting collard greens indoors isn't always necessary in our climate, but it can give you a head start, especially for an early summer harvest. If you want to go this route, start your seeds indoors from early to late March, about four weeks before you plan to transplant them outside.

Use seed trays with a good seed-starting mix and keep them warm and consistently moist. Bottom watering is a great way to keep the soil damp without encouraging fungal diseases. While our springs here are moderate, this can help you jump ahead of the game.

Transplant your collard green seedlings outdoors from early April through early May, after the danger of a hard frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week.

Space them 18-24 inches apart to give them plenty of room to grow. Keep an eye on the weather forecast around transplant time, as we can still get some cool snaps and late frosts that could damage young plants.

Direct sowing collard greens is a perfectly viable option in the Southeast, and it's often easier than starting them indoors. You can direct sow from late March through early August, giving you plenty of flexibility.

Prepare your soil by loosening it and adding compost. Make sure the soil temperature is at least 60°F for good germination. Sow seeds about ½ inch deep and thin seedlings to 18-24 inches apart once they emerge.

Collard greens need consistent moisture to produce tender, flavorful leaves, but they don't like to be waterlogged. While they're more heat-tolerant than other brassicas, consistent watering is still key, especially during our hot summers.

During the hotter months, you'll likely need to water your collard greens deeply a couple of times a week, providing about 1-1.5 inches of water each time. Use the "finger test" – if the top 2 inches of soil feel dry, it's time to water. With our humid climate, it's best to water at the base of the plants to avoid creating a humid environment around the leaves, which can encourage fungal diseases.

Watch for signs of underwatering, like wilting leaves, or overwatering, like yellowing leaves. A good layer of mulch around your collard greens will help retain moisture in our clay soil and suppress weeds, which is a big help during our long, humid summers.

You can expect your first harvest of collard greens from early June through early November, depending on when you planted them. Look for lower leaves that are 10-12 inches long and a deep green color.

To harvest, simply cut or snap off the outer leaves, leaving the top rosette intact. This allows the plant to continue producing new leaves throughout the season. Many gardeners in the South swear that collard greens taste even better after a light frost, as the cold temperatures sweeten the leaves.

As the first frost approaches in late October, you can cover your plants with a blanket or row cover to extend the harvest a bit longer. Even after a frost, you can often still salvage some tasty leaves.

Here are some common problems you might encounter growing collard greens in the Southeast:

Cabbage Worms *What it looks like:* Smooth green caterpillars chewing irregular holes in leaves, leaving dark green droppings. You might also see white butterflies fluttering around. *What causes it:* These are the larvae of white cabbage butterflies, and they can have multiple generations during our long, warm growing season. *How to fix/prevent it:* Bt spray is very effective. Floating row covers will prevent the butterflies from laying eggs. You can also handpick the caterpillars. Interplanting with aromatic herbs like thyme and sage can help deter them, and encourage parasitic wasps.

Aphids *What it looks like:* Clusters of tiny green, black, or white insects on stems and the undersides of leaves. You might also notice sticky honeydew and curled or distorted new growth. *What causes it:* Aphids are sap-sucking insects that reproduce rapidly, especially in warm weather. Ants often "farm" them for their honeydew, so keep ant populations in check. *How to fix/prevent it:* A strong spray of water can knock them off. Encourage ladybugs and lacewings, which are natural predators. Insecticidal soap is effective for heavy infestations, and neem oil works systemically. Avoid over-fertilizing with nitrogen, as it attracts aphids.

Cabbage Loopers *What it looks like:* Similar to cabbage worms, but these caterpillars move in a looping motion. They also chew holes in leaves. *What causes it:* These are another type of caterpillar that thrives in our warm climate. *How to fix/prevent it:* Similar to cabbage worms, Bt spray is very effective. Handpicking, row covers, and attracting beneficial insects also help.

Downy Mildew *What it looks like:* Yellow patches on the upper side of leaves, with fuzzy gray-purple growth on the undersides. Leaves eventually turn brown and die from the bottom up. *What causes it:* This fungal disease spreads in cool, humid conditions via wind-carried spores, which is common during our wet-summer weather. *How to fix/prevent it:* Remove affected leaves immediately. Improve air circulation around your plants by spacing them properly. Water at the base of the plants, and avoid overhead watering. Copper-based fungicides can be used as a preventative measure.

Southeast Specific Challenges Our hot and humid summers, combined with frequent rainfall, create ideal conditions for fungal diseases and pest infestations. Be vigilant about checking your plants regularly and take action quickly when you spot problems. Good air circulation, proper watering techniques, and preventative measures like neem oil and Bt spray can go a long way in keeping your collard greens healthy and productive.

Companion planting can be a great way to improve the health and productivity of your collard greens. Onions and garlic are good companions because their strong scent can help deter pests like aphids and cabbage moths. Beets and potatoes are also good companions, as they don't compete for the same nutrients in the soil. Dill attracts beneficial insects that prey on pests like cabbage worms.

Avoid planting strawberries or tomatoes near your collard greens. Strawberries can attract slugs and snails, which can also damage collard greens. Tomatoes can attract pests like aphids and whiteflies, which can spread to your collard greens.