Collard Greens in Zone 5B — Mid-Atlantic

Collard greens are a Southern staple that thrives surprisingly well here in the Mid-Atlantic. Their slightly bitter, earthy flavor deepens and sweetens after a touch of frost, making them a perfect addition to fall and winter meals. Plus, their large, architectural leaves add visual interest to your garden long after other crops have faded.

Don't let our humid summers or the occasional deer deter you. With a little planning, you can enjoy a bountiful harvest of collards throughout our 178-day growing season. Timing is key, and we'll walk you through it.

Starting collard greens indoors gives you a head start, but it's not strictly necessary in our climate. If you're aiming for an especially early harvest or want to protect seedlings from early-season pests, it's a good option.

Start your seeds indoors from mid-March through early April, about four weeks before you plan to transplant. Use seed trays or small pots filled with a good seed-starting mix, keep them warm (around 70°F), and provide plenty of light – a sunny windowsill or grow light works well. Water from the bottom to encourage strong root growth and prevent damping off.

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

Choose a spot with full sun to partial shade, and space your plants 18-24 inches apart. Our unpredictable spring weather can bring late cold snaps, so keep an eye on the forecast and be prepared to cover your young plants if necessary.

Direct sowing collard greens is a straightforward method that works well in our climate. You can direct sow from early April through mid-July, giving you flexibility for succession planting.

Prepare your soil by loosening it and adding compost. Ensure the soil temperature is at least 60°F for good germination. Sow seeds ½ inch deep, and thin seedlings to 18-24 inches apart once they emerge. Direct sowing can be more susceptible to pests like flea beetles, so monitor your seedlings closely.

Collard greens need consistent moisture to thrive, especially during our humid summers. Aim for about 1 inch of water per week, either from rainfall or irrigation.

The "finger test" is a reliable way to check soil moisture: stick your finger into the soil about 2 inches deep. If it feels dry, it's time to water. Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our humid climate.

During hotter periods, you might need to water more frequently. Signs of underwatering include wilting leaves, while yellowing leaves can indicate overwatering. A layer of mulch, like straw or shredded leaves, helps retain moisture and suppress weeds, a common challenge in Mid-Atlantic gardens.

You can expect your first harvest of collard greens from mid-June through late October, about 75 days after planting. The best time to harvest is when the lower leaves are 10-12 inches long.

To harvest, simply snap off the outer leaves, leaving the central rosette 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 the weather cools.

As our first frost approaches in mid- October, harvest any remaining large leaves to prevent damage. Even after a frost, the core of the plant may survive, providing a small, late-season harvest.

Here are some common problems you might encounter growing collard greens in the Mid-Atlantic:

Cabbage Worms

• What it looks like: Smooth green caterpillars chewing irregular holes in leaves. You might also see dark green droppings and white butterflies fluttering around.
• What causes it: Larvae of white cabbage butterflies. They love our warm, humid summers, leading to multiple generations per season.
• How to fix/prevent it: Bt spray is very effective. Floating row covers prevent butterflies from laying eggs. Handpick caterpillars. Interplant with aromatic herbs like thyme and sage.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Rapidly reproducing sap-sucking insects. Populations explode in warm weather.
• How to fix/prevent it: Strong water spray to knock them off. Encourage ladybugs and lacewings. Insecticidal soap for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer.

Cabbage Loopers

• What it looks like: Similar to cabbage worms, but these are light green with white stripes down their sides. They move in a looping motion.
• What causes it: These are the larvae of a gray-brown moth. They thrive in the warm weather.
• How to fix/prevent it: Similar to cabbage worms, use Bt spray, handpick, and use row covers. Keep an eye out for eggs on the underside of leaves.

Downy Mildew

• What it looks like: Yellow patches on leaf tops with fuzzy gray-purple growth on undersides. Leaves brown and die from the bottom up.
• What causes it: Oomycete pathogen that spreads in cool, humid conditions via wind-carried spores.
• How to fix/prevent it: Remove affected leaves immediately. Improve air circulation. Water at the base. Copper-based fungicides for prevention.

Mid-Atlantic Specific Challenges: Our moderate-to-hot summers and humid climate create ideal conditions for many pests and diseases that affect collard greens. Regular monitoring and proactive measures, like good air circulation and appropriate watering techniques, are essential for a healthy harvest.

Companion planting can help your collard greens thrive in the Mid-Atlantic.

Good companions include:

• Onion and Garlic: Their strong scent deters many pests.
• Beets: They help loosen the soil, improving drainage.
• Potatoes: They don't compete for the same nutrients and can help shade the soil, keeping it cooler during our summers.
• Dill: Attracts beneficial insects like ladybugs and lacewings, which prey on aphids.

Avoid planting collard greens near:

• Strawberries: Both are susceptible to similar fungal diseases that can spread easily in our humid climate.
• Tomatoes: They can attract similar pests, like aphids and whiteflies, increasing the risk of infestation.