Collard Greens in Zone 6A — Southeast

Collard greens are a Southern staple for a reason. They're delicious braised, sautéed, or even added raw to salads when the leaves are young. Here in the Southeast, we can enjoy a long harvest of these nutritious greens, making them a rewarding addition to any garden.

Our hot and humid summers can bring challenges like fungal diseases and pests, but with proper timing and care, you can easily grow a bountiful crop of collards. Our long, 198-day growing season gives you plenty of flexibility.

Starting collard greens indoors gives you a jump start, but it's not always necessary, given our long growing season. If you want to get a head start, begin sowing seeds indoors from early to late March, about four weeks before you plan to transplant. Use seed trays filled with a good seed-starting mix, and keep them warm and consistently moist.

Bottom watering can help prevent damping-off, a common issue with seedlings. Place the tray in a shallow dish of water and let the soil soak it up from the bottom. The moderate spring here in the Southeast makes indoor starting fairly straightforward.

Transplant your collard green seedlings outdoors from early April through early May. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This will help them adjust to the Southeast's sun and wind.

Space the seedlings 18-24 inches apart in well-drained soil. Keep an eye on the weather forecast around transplant time; late frosts can still occur in early April, so be prepared to cover your young plants if needed.

Direct sowing collard greens is a simple and effective method, especially with our reliable summer rains. Sow seeds from late March through late July, ensuring the soil temperature is at least 60°F. Prepare the soil by loosening it and adding compost or other organic matter.

Plant seeds about ½ inch deep and space them 18-24 inches apart. Thin the seedlings once they emerge, leaving the strongest plants. Direct sowing avoids transplant shock and allows the plants to establish deep roots.

Collard greens need consistent moisture to produce tender, flavorful leaves. While they're more heat-tolerant than some other brassicas, they still need regular watering, especially during our hot and humid summers. Aim for about 1 inch of water per week, whether from rainfall or irrigation.

The finger test is a good way to check soil moisture: stick your finger about 2 inches into the soil near the base of the plant. If it feels dry, it's time to water. During the hottest part of the summer, you may need to water more frequently.

Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our humid climate. Signs of underwatering include wilting leaves and slow growth. Overwatering can lead to yellowing leaves and root rot. Mulching around your collard greens with straw or wood chips helps retain moisture and suppress weeds, a great practice in our climate.

You can expect your first harvest of collard greens from early June through early November, about 75 days after planting. The best time to harvest is when the lower leaves are 10-12 inches long. Look for healthy, green leaves without any yellowing or blemishes.

To harvest, simply cut or snap off the outer leaves, leaving the top rosette of leaves intact. This allows the plant to continue producing new leaves throughout the season. The flavor of collard greens actually sweetens after a light frost, so don't be afraid to leave them in the garden as late as possible.

As our first frost approaches in late October, you can cover your plants with a frost blanket to extend the harvest a bit longer. Even after a frost, the leaves are often still edible and delicious.

Here are some common problems you might encounter with 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 your plants. *What causes it:* The larvae of white cabbage butterflies. They can have multiple generations in our long, warm 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 and interplant with aromatic herbs like thyme and sage to deter them. Encourage parasitic wasps, which are natural predators.

Aphids *What it looks like:* Clusters of tiny insects (green, black, or white) on stems and leaf undersides. You may notice a sticky honeydew residue and curled or distorted new growth. *What causes it:* These sap-sucking insects reproduce rapidly, especially in warm weather. Ants often farm them for their honeydew. *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 excess nitrogen fertilizer, as it attracts them.

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:* The larvae of moths. They thrive in warm, humid conditions. *How to fix/prevent it:* Handpick them off the plants. Bt spray is also effective. Encourage beneficial insects like parasitic wasps.

Downy Mildew *What it looks like:* Yellow patches on leaf tops with fuzzy gray-purple growth on the undersides. Leaves brown and die from the bottom up. *What causes it:* An oomycete pathogen that spreads in cool, humid conditions via wind-carried spores. *How to fix/prevent it:* Remove affected leaves immediately. Improve air circulation around your plants. Water at the base, never overhead. Copper-based fungicides can be used for prevention. Plant resistant varieties if available.

Southeast Specific Challenges: The hot, humid summers in the Southeast create a perfect environment for fungal diseases like downy mildew. The humidity also encourages pests like aphids and cabbage worms. Be vigilant about monitoring your plants and take action quickly to prevent problems from escalating.

Companion planting can help your collard greens thrive. Onions and garlic are good companions because their strong scent deters pests. Beets and potatoes are also beneficial, as they don't compete for the same nutrients in the soil. Dill attracts beneficial insects that prey on pests like aphids and cabbage worms.

Avoid planting collard greens near strawberries or tomatoes. Strawberries are susceptible to verticillium wilt, which can also affect collards. Tomatoes can attract pests that also attack collards, increasing the risk of infestation.