Collard Greens in Zone 9A — Florida

Collard greens are a Southern staple, and here in Zone 9A Florida, we can enjoy them almost year-round. Their slightly bitter, earthy flavor is delicious braised, sauteed, or even added to smoothies. Plus, they're packed with nutrients and surprisingly easy to grow in our unique climate.

Our Florida gardening calendar is different, and summer is the slow season. But with collards, you can plant in fall, harvest in winter, and even get a spring crop before the heat really kicks in. That long 327-day growing season means you have plenty of opportunities to get it right, even with our humidity and occasional pests.

Starting collard greens indoors isn't essential, but it can give you a head start, especially for an early spring crop. If you want to go this route, aim to start your seeds indoors from late December through mid January, about four weeks before you'd like to transplant them outside.

Use seed trays or small pots filled with a good seed-starting mix. Keep them warm and provide plenty of light, either with a grow light or a sunny windowsill. Bottom watering helps prevent damping-off, so set the tray in a shallow dish of water and let the soil soak it up from the bottom. Remember, our spring is reversed; starting early gives you an advantage as the weather warms (eventually!).

Transplant your collard green seedlings outdoors from early February through early March. 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.

Space your plants 18-24 inches apart to give them plenty of room to grow. Keep an eye on the weather! A late cold snap can happen, so be prepared to cover them if temperatures dip near freezing.

Direct sowing collard greens is a great option, especially for a fall or winter harvest. You can direct sow from mid January through late September. The biggest advantage is skipping the transplanting step, but be aware that seedlings are more vulnerable to pests and diseases.

Prepare your soil well, ensuring it's loose and fertile. Sow seeds about ½ inch deep and keep the soil consistently moist until they germinate. Thin seedlings to 18-24 inches apart once they have a few true leaves.

Watering is crucial for healthy collard greens, especially in our Florida climate. While they're more heat-tolerant than some other brassicas, consistent moisture is key to preventing bitterness and encouraging tender leaves.

During the cooler months (fall through spring), you'll likely only need to water once or twice a week, depending on rainfall. In the hotter, drier periods of spring and fall, increase watering to 2-3 times per week. Use the finger test: stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. Aim for about 1-1.5 inches of water per week, whether from rain or irrigation.

Water at the base of the plants to avoid wetting the leaves, which can contribute to fungal diseases in our humid environment. Overwatering can lead to root rot, while underwatering will cause the leaves to wilt and become tough. Mulching around your plants with pine straw or wood chips helps retain moisture and suppress weeds.

You can expect your first harvest of collard greens about 75 days after planting. In Florida, that means you could be harvesting from early April through early January, depending on when you planted.

Harvest the lower leaves when they're 10-12 inches long. Simply snap or cut them off near the base of the plant, leaving the top rosette to continue growing. The flavor of collard greens actually sweetens after a light frost, so don't be afraid to leave them in the garden as long as possible.

Collard greens are a continuous harvest crop, meaning you can keep picking leaves as needed. As the first frost approaches in late December, you can harvest the entire plant or cover it to extend your harvest a bit longer.

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

Cabbage Worms

• What it looks like: Smooth green caterpillars chewing irregular holes in leaves, often leaving dark green droppings behind. You might also see white cabbage butterflies fluttering around.
• What causes it: The larvae of white cabbage butterflies, which thrive in our warm climate and can produce multiple generations in a season.
• How to fix/prevent it: Bt spray is very effective and safe for humans. Floating row covers can prevent the butterflies from laying eggs. You can also handpick the caterpillars or interplant with aromatic herbs like thyme and sage to deter them.

Aphids

• What it looks like: Clusters of tiny, soft-bodied insects (green, black, or white) on stems and leaf undersides. Sticky honeydew residue and curled or distorted new growth.
• What causes it: Rapidly reproducing sap-sucking insects that love warm weather. Ant colonies may even "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 can be used for heavy infestations, and neem oil works systemically. Avoid excess nitrogen fertilizer, which attracts them.

Cabbage Loopers

• What it looks like: Similar to cabbage worms, but these are light green with white stripes down their backs. They move in a looping motion.
• What causes it: The larvae of moths. Like cabbage worms, they thrive in our warm climate.
• How to fix/prevent it: Same as for cabbage worms: Bt spray, row covers, handpicking, and attracting beneficial insects.

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: A fungal disease that spreads in cool, humid conditions via wind-carried spores. Our humidity makes us particularly susceptible.
• How to fix/prevent it: Remove affected leaves immediately. Improve air circulation by spacing plants properly. Water at the base of the plants, never overhead. Copper-based fungicides can be used for prevention.

Florida Specific Challenges: Our hot heat, very-high humidity, and wet-summer rainfall create the perfect environment for pests and diseases to flourish. Choosing nematode-resistant varieties and practicing good garden hygiene (removing debris, proper watering) is crucial for success with collard greens in Florida.

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

Avoid planting strawberries or tomatoes near your collard greens. Strawberries are susceptible to some of the same fungal diseases, and tomatoes can attract pests that also target collards.