Collard Greens in Zone 7B — Mid-Atlantic

Collard greens are a Southern staple that thrive in our Mid-Atlantic four seasons. They offer a unique, slightly bitter flavor that's delicious braised, sautéed, or added to soups. Plus, they are incredibly productive, providing harvests from early summer all the way through fall. The real satisfaction comes from knowing you’re eating something healthy and delicious grown right here in your backyard, even when the weather gets humid.

We definitely have our share of challenges here in Zone 7B, including deer, Japanese beetles, and our heavy clay soil. But with careful timing and a little know-how, you can enjoy a bountiful collard green harvest. Our 214-day growing season gives you plenty of time to get these greens established and producing.

Starting collard greens indoors gives you a head start, especially if you're aiming for an early harvest. You can start seeds indoors from late February through mid March, about four weeks before you plan to transplant. This is especially useful when spring weather is variable, and you want to ensure seedlings are strong enough to withstand any late frosts.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist, and consider bottom watering to prevent damping-off. A sunny windowsill or grow lights will provide the warmth and light they need to germinate and grow.

Transplant your collard green seedlings outdoors from early to late April. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind, reducing transplant shock.

Space the seedlings 18-24 inches apart to give them plenty of room to grow. Our springs can be unpredictable, so watch for late frost warnings and be prepared to cover your young plants if necessary.

Direct sowing collard greens is a viable option, particularly for a later harvest. Sow seeds directly into the garden from mid March through early August. Direct sowing avoids transplant shock.

Prepare the soil by loosening it and adding compost. Ensure the soil temperature is at least 60°F for good germination. Plant seeds ½ inch deep, spacing them 18-24 inches apart. Keep the soil consistently moist until the seedlings emerge.

Collard greens need consistent moisture to produce tender, flavorful leaves, but overwatering is a problem in our humid climate. During the hotter months, you might need to water more frequently. An inch of water per week, either from rain or irrigation, is usually sufficient.

Use the "finger test" to determine if your plants need water. Stick your finger about two inches deep into the soil near the base of the plant. If the soil feels dry, it's time to water. Water deeply at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our humid summers.

Signs of underwatering include wilting leaves and slow growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch around the base of the plants helps retain moisture and suppress weeds, but be sure not to pile it against the stem.

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 and a healthy green color. Don't wait too long, or they can become tough.

Harvest by cutting the outer leaves with a sharp knife or garden shears, leaving the top rosette intact. This allows the plant to continue producing new leaves throughout the season. Many gardeners find that the flavor sweetens after the first frost, so don't be afraid to leave some plants in the ground as late as possible.

As the first frost approaches in early November, you can harvest the entire plant if you prefer, or cover it to extend the harvest a bit longer. They are frost hardy, so don't be afraid to leave them out.

Here are some common problems you might encounter growing collard greens in our area:

Cabbage Worms

• What it looks like: Smooth green caterpillars on brassica leaves, with irregular holes chewed in the leaves. You might also see dark green droppings and white butterflies fluttering around your plants.
• What causes it: These are the larvae of white cabbage butterflies. They can have multiple generations per season in our warm climate.
• How to fix/prevent it: Bt spray is very effective. Floating row covers can prevent the butterflies from laying eggs. Handpick the caterpillars when you see them. Interplanting with aromatic herbs like thyme and sage can help deter them. Encourage parasitic wasps, which are natural predators.

Aphids

• What it looks like: Clusters of tiny, soft-bodied insects (green, black, or white) on stems and the undersides of leaves. You might also see sticky honeydew residue and curled or distorted new growth.
• What causes it: These are sap-sucking insects that reproduce rapidly. Populations can explode in warm weather. Ant colonies may farm them for honeydew.
• How to fix/prevent it: A strong spray of water can knock them off the plants. Encourage ladybugs and lacewings, which are natural predators. Insecticidal soap can be used for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer, which 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: These are the larvae of moths. They thrive in warm weather.
• How to fix/prevent it: Use Bt spray, handpick caterpillars, and use floating row covers, just like with cabbage worms.

Downy Mildew

• What it looks like: Yellow patches on the tops of leaves with fuzzy, gray-purple growth on the undersides. Leaves brown and die from the bottom up.
• What causes it: This is caused by 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.

Mid-Atlantic Specific Challenges: Our moderate-to-hot summers and humid conditions can create a perfect environment for pests and diseases to thrive on collard greens. Regular monitoring, good air circulation, and prompt action are key to keeping your plants healthy. Also, deer pressure can be significant, so consider fencing or deer repellent to protect your crop.

Companion planting can really boost your collard green crop here in the Mid-Atlantic. Onions and garlic are great companions because their strong scent deters many pests that bother collards. Beets also work well, as they don't compete for the same nutrients and can help loosen the soil. Potatoes are beneficial because they attract beneficial insects that prey on collard pests. Dill attracts beneficial insects, like ladybugs and lacewings, that will help keep aphids in check.

Avoid planting strawberries near your collards, as they can attract slugs and snails, which will also feed on your greens. Tomatoes are also not good companions because they compete for the same nutrients and can attract some of the same pests.