Cabbage in Zone 9A — Florida

Cabbage is a rewarding crop to grow in Florida's Zone 9A. Few things beat the taste of fresh, homegrown cabbage, especially when you've nurtured it through our mild winter. Plus, it's incredibly versatile in the kitchen, from slaws to stir-fries, and there’s a real satisfaction in harvesting a beautiful head you grew yourself.

Our Florida gardening calendar is different, and while the summer heat and humidity can be intense, growing cabbage is all about timing. By planting in fall and harvesting in winter, you can avoid the worst of the challenges and take full advantage of our long, 327-day growing season.

To get a head start on your spring cabbage harvest, start your seeds indoors from late November through late December. This gives the seedlings about 6 weeks to develop before transplanting. Use seed trays or small pots filled with a good seed-starting mix.

Keep the soil consistently moist, and consider bottom watering to avoid damping off, which can be a problem in our humid climate. Provide warmth and plenty of light – a grow light works wonders, especially since our days are shorter in the winter. Remember, our spring is reversed: we start planting cool-season crops when other regions are thinking about their last frost.

Transplant your cabbage seedlings outdoors from mid January through mid February. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sunlight and temperature changes.

Space the plants 12-18 inches apart in a sunny spot with well-drained soil. While our winters are mild, keep an eye out for any unexpected cold snaps. A frost cloth can provide extra protection if needed.

Cabbage needs consistent moisture, but overwatering can be just as detrimental as underwatering, especially with our high humidity. Aim for about 1 inch of water per week, but adjust based on rainfall. During our drier periods in fall and spring, you’ll need to supplement with irrigation.

Use the finger test: stick your finger about 2 inches deep into the soil. 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 conditions.

Pay attention to your plants. Wilting leaves can indicate underwatering, while yellowing leaves or stunted growth can signal overwatering. A layer of mulch, like pine straw, helps retain moisture and suppress weeds, which is a bonus given our sandy soil.

Your first cabbage harvest should be ready from late March through mid May, about 70 days after transplanting. The key is to feel the head: it should be firm and solid when squeezed. Also, make sure it has reached the full size expected for the variety you're growing.

To harvest, use a sharp knife to cut the head at the base of the plant. Leave the outer leaves intact; they can sometimes produce smaller side shoots for a later harvest. As our first frost approaches in late December, harvest any remaining heads, even if they're not quite fully mature. They can still be used in cooking.

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

• Cabbage Worms
• What it looks like: Smooth green caterpillars on brassica leaves. Irregular holes chewed in leaves. Dark green droppings. White butterflies hovering around plants.
• What causes it: Larvae of white cabbage butterflies. Multiple generations per season in warm climates.
• How to fix/prevent it: Bt spray is very effective. Floating row covers prevent egg laying. Handpick caterpillars. Interplant with aromatic herbs (thyme, sage). Encourage parasitic wasps.
• Cabbage Loopers
• What it looks like: Similar to cabbage worms, these are pale green caterpillars that move in a looping motion. They also chew holes in leaves.
• What causes it: A different type of moth, but the result is the same: hungry larvae. They thrive in warm, humid conditions.
• How to fix/prevent it: Bt spray works well on loopers too. Handpicking is also effective. Keep an eye out for eggs on the undersides of leaves.
• Splitting
• What it looks like: The cabbage head cracks open.
• What causes it: Inconsistent watering. A sudden heavy watering after a dry spell causes the head to swell too quickly, leading to splitting.
• How to fix/prevent it: Maintain consistent soil moisture. Mulch helps. If heavy rain is expected, consider harvesting mature heads early.
• Clubroot
• What it looks like: Stunted growth, wilting in afternoon heat, yellowing leaves. Roots are swollen, distorted, and club-shaped when dug up.
• What causes it: Soil-borne pathogen (Plasmodiophora brassicae) that persists in soil for 10+ years. Favors acidic, wet soil.
• How to fix/prevent it: Raise soil pH to 7.0-7.2 with lime. Improve drainage. Rotate brassicas on a 7-year cycle. Remove and destroy infected plants (don't compost). Start transplants in sterile mix.

Florida Specific Challenges: Our hot, humid summers and wet-summer rainfall can exacerbate fungal diseases and pest problems. Consistent monitoring and proactive measures are key to keeping your cabbage healthy. Nematodes can also be an issue in our sandy soil, so consider using nematode-resistant varieties.

Companion planting can really help your cabbage thrive. Green beans fix nitrogen in the soil, benefiting cabbage's growth. Celery deters cabbage white butterflies, reducing cabbage worm infestations. Onions and dill also repel pests. Potatoes can help break up the soil, improving drainage.

Avoid planting cabbage near tomatoes, strawberries, and peppers. Tomatoes and strawberries can attract similar pests, increasing the risk of infestation. Peppers compete for the same nutrients in the soil, potentially stunting cabbage growth.