Cabbage in Zone 9A — Desert Southwest

Cabbage might not be the first thing that comes to mind for desert gardening, but its crisp texture and mild flavor make it a welcome addition to our tables, especially when homegrown. Think fresh slaws, stir-fries, or even stuffed cabbage rolls using your own harvest. Plus, there's a real satisfaction in growing your own food in our challenging climate.

Sure, our extreme heat and alkaline soil present hurdles, but with careful timing and a few desert-gardening tricks, you can absolutely grow cabbage here. Our 298-day growing season gives us a fantastic window for cool-season crops like cabbage. Let’s get started!

Starting cabbage indoors gives you a head start (pun intended!) and helps you avoid the worst of our early temperature swings. Aim to sow your seeds from mid December through early January. This gives you about 6 weeks to get them strong before transplanting.

Use seed trays or small pots filled with a good quality seed-starting mix. Keep the soil consistently moist, but not soggy. Bottom watering is your friend here – set the tray in a shallow dish of water and let the soil soak it up from the bottom. Provide warmth (around 70°F) and plenty of light, either from a sunny window or a grow light. Remember, our spring character is very-early, so you want robust seedlings ready to go.

Transplant your cabbage seedlings outdoors from early February through early March. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This prevents transplant shock.

Choose a spot with full sun (6-8 hours) and well-drained soil. Space the plants 12-18 inches apart. Our weather can still be unpredictable at this time, so keep an eye out for late frosts and be prepared to cover your seedlings if needed.

Watering is critical for cabbage, especially in our arid Desert Southwest climate. Consistent moisture is key to preventing the heads from splitting. However, heavy watering after a dry spell can also cause them to crack open. Finding the right balance is essential.

During the cooler months (February-March), aim to water deeply about once a week, providing about 1 inch of water. As temperatures rise in April and May, increase watering to 2-3 times a week, providing 1-2 inches of water each time. Use the finger test: stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our arid climate.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. A layer of organic mulch around your cabbage plants helps retain soil moisture and regulate soil temperature.

You can expect your first cabbage harvest from mid April through late May, about 70 days after transplanting. The key is to feel the head. It should be firm and solid when squeezed, indicating it's tightly packed and mature. Also, make sure the head 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; sometimes smaller heads will form from the stem. As our first frost approaches in early December, harvest any remaining heads, even if they're not fully mature. They'll still be delicious in soups and stews.

Here are some common cabbage problems we face in the Desert Southwest:

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, but loopers move in a distinctive "looping" motion. They also chew holes in leaves.
• What causes it: Larvae of cabbage looper moths. They thrive in warm weather.
• How to fix/prevent it: Bt spray is effective. Handpick loopers. Encourage beneficial insects.

Splitting

• What it looks like: The cabbage head cracks open.
• What causes it: Inconsistent watering, especially after a period of drought followed by heavy watering. Rapid growth spurts can also contribute.
• How to fix/prevent it: Maintain consistent soil moisture. Water deeply and regularly, especially during dry spells. Mulch around the plants to help retain moisture. Harvest heads as soon as they are mature.

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.

Desert Southwest Specific Challenges: Our extreme heat can stress cabbage plants, making them more susceptible to pests and diseases. The monsoon moisture can create favorable conditions for fungal diseases. Alkaline soil can also limit nutrient availability. Careful watering, soil amendments, and pest control are crucial for success.

Companion planting can really help your cabbage thrive in our Desert Southwest gardens.

Good companions for cabbage include green beans, celery, onion, potato, and dill. Green beans fix nitrogen in the soil, benefiting cabbage growth. Celery repels cabbage white butterflies. Onions deter pests. Potatoes don't compete for the same nutrients. Dill attracts beneficial insects that prey on cabbage pests.

Avoid planting cabbage near tomatoes, strawberries, or peppers. Tomatoes and peppers can attract similar pests and diseases. Strawberries can inhibit cabbage growth. In our limited space, it's best to optimize your plant pairings.