Collard Greens in Zone 8A — Southeast

Collard greens are a staple in Southern cooking, and for good reason. Their slightly bitter flavor mellows out beautifully when cooked, and they're incredibly versatile – braised, sautéed, or even added to soups. Plus, here in Zone 8A, our long growing season and reliable summer rain make them a really satisfying crop to grow.

Our hot, humid summers can bring some challenges, like fungal diseases and those pesky Japanese beetles. But with a little planning and attention to timing, you can easily enjoy a bountiful harvest of collards from mid-May all the way into late November. Our 245-day growing season gives you plenty of flexibility.

Starting collard greens indoors gives you a head start, but it's not strictly necessary in our climate. If you want to get a jump on the season, aim to start your seeds indoors from early February through early March, about four weeks before you plan to transplant them.

Use seed trays with a good seed-starting mix, and keep them warm and consistently moist. Bottom watering is a great trick to avoid damping off. A simple grow light will ensure strong, healthy seedlings. Since our spring is fairly moderate, you don't have to rush, but this method gives you a bit of a buffer.

Transplant your collard green seedlings outdoors from mid March through mid April. Before you do, be sure to harden them off by gradually exposing them to outdoor conditions for about a week.

Space your plants 18-24 inches apart to allow for good air circulation, which is key in our humid climate. Keep an eye on the weather forecast – a late cold snap could set them back, so be ready to cover them if needed.

Direct sowing collard greens is a perfectly viable option here in the Southeast. You can sow seeds directly into the garden from early March through mid August.

Make sure the soil is well-prepared and 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. Direct sowing is less work initially, but you'll need to stay on top of weeding and watering, especially during our long, hot summer.

Collard greens need consistent moisture to produce tender, flavorful leaves. While they're more heat-tolerant than some other brassicas, don't let them dry out, especially during our hot and humid summers.

During the spring and fall, when temperatures are milder and we get more frequent rainfall, you might only need to water once or twice a week, providing about 1 inch of water each time. Use the finger test – stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. During the heat of summer, especially if we're experiencing a dry spell, you may need to water every other day, or even daily, to keep the soil consistently moist.

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, on the other hand, can lead to root rot and yellowing leaves. A layer of mulch around your plants will help retain moisture and suppress weeds, which is a win-win in our gardens.

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

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 it sweetens the leaves.

As our first frost approaches in mid November, you can either harvest the entire plant or cover it to extend the harvest a bit longer. Collards are pretty cold-hardy, so you might be surprised how long you can keep them going.

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

Cabbage Worms

• What it looks like: Smooth green caterpillars chewing irregular holes in leaves, leaving behind dark green droppings. You might also see white butterflies fluttering around.
• What causes it: These are the larvae of cabbage white butterflies, and they can go through multiple generations in our long, warm season.
• How to fix/prevent it: Bt spray is very effective. Floating row covers can prevent the butterflies from laying eggs. You can also handpick the caterpillars and interplant with aromatic herbs like thyme and sage to deter them.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. You might also see sticky honeydew and curled or distorted new growth.
• What causes it: These sap-sucking insects reproduce rapidly, especially in warm weather. Ants often protect them in exchange for 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 or neem oil can also be effective. Avoid over-fertilizing with nitrogen, 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: These are the larvae of a gray-brown moth.
• How to fix/prevent it: Bt spray is effective. Handpick them off the plants. Encourage beneficial insects like parasitic wasps.

Downy Mildew

• What it looks like: Yellow patches on the upper surface of leaves, with fuzzy gray-purple growth on the undersides. Leaves will eventually brown and die.
• What causes it: This fungal disease thrives in cool, humid conditions and spreads through wind-borne spores.
• How to fix/prevent it: Remove affected leaves immediately and improve air circulation around your plants. Water at the base, and consider using a copper-based fungicide as a preventative measure.

Southeast Specific Challenges: Our hot, humid climate and wet-summer rainfall create ideal conditions for fungal diseases like downy mildew. The long growing season also means multiple generations of pests like cabbage worms and aphids. Regular monitoring and proactive measures are key to keeping your collard greens healthy and productive.

Companion planting can be a great way to boost 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 also make good neighbors, as they don't compete for the same nutrients in the soil. Dill attracts beneficial insects like ladybugs and lacewings, which prey on aphids and other pests.

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.