Cabbage in Zone 9B — 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. Imagine fresh coleslaw on a hot day or a hearty cabbage and sausage soup during our brief cool season. Plus, you’ll get a real sense of accomplishment growing your own food in this challenging climate!

Don't let the Desert Southwest's reputation intimidate you. With our 313-day growing season, careful timing, and a few tricks, you can absolutely grow Cabbage here. We'll focus on our two growing seasons and avoid the extreme heat of summer, turning potential challenges into opportunities.

To get a jump start on the spring harvest, start your Cabbage seeds indoors from early to late December. This gives them a head start before our very-early spring kicks into gear. Use seed trays or small pots filled with a good quality seed-starting mix.

Keep the soil consistently moist (but not soggy) by bottom watering. Place the tray in a shallow container of water, allowing the soil to soak it up from the bottom. This prevents damping-off disease and encourages strong root development. Provide warmth with a heat mat and plenty of light with grow lights until seedlings emerge.

Transplant your Cabbage seedlings outdoors from late January through mid February. Before transplanting, harden them off over about a week by gradually exposing them to outdoor conditions. This helps them adjust to the sun and wind.

Space the seedlings 12-18 inches apart in well-draining soil. Even in late January, be prepared for unexpected temperature swings, and have frost cloth ready to protect your young plants if needed.

Cabbage needs consistent moisture to thrive, but overwatering can be just as detrimental, especially in our alkaline soil. Aim to keep the soil evenly moist, but not waterlogged. Strive for about 1-1.5 inches of water per week, adjusting based on rainfall.

Use the "finger test" to check soil moisture – stick your finger about 2 inches deep into the soil near the base of the plant. If it feels dry, it's time to water. Water deeply at the base of the plant to encourage strong root growth and reduce the risk of fungal diseases in our arid climate. Avoid overhead watering, especially as temperatures rise.

During the monsoon season, monitor the soil moisture closely and adjust your watering schedule accordingly. Watch for signs of underwatering (wilting, yellowing leaves) and overwatering (yellowing leaves, stunted growth). A layer of organic mulch, like compost, will help retain moisture and regulate soil temperature, but keep it away from the stem to prevent rot. Remember that heavy watering after a dry spell can cause heads to split.

You can expect your first Cabbage harvest from early April through late May, about 70 days after transplanting, depending on the variety. The key is to feel the head – it should be firm and solid when squeezed. The head should also be a good size 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 develop from the stem after the main head is harvested. As our first frost approaches in mid- December, harvest any remaining heads, even if they are on the smaller side, as they won't survive a hard freeze.

Here are a few common problems to watch out for when growing Cabbage 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: Pale green caterpillars that move in a looping motion. They chew large, irregular holes in leaves.
• What causes it: Similar to cabbage worms, cabbage loopers thrive in warm weather and can quickly defoliate plants.
• How to fix/prevent it: Use Bt spray. Handpick loopers. Encourage natural predators like birds and lacewings.

Splitting

• What it looks like: The cabbage head cracks open, often after a period of heavy rain or inconsistent watering.
• What causes it: Rapid changes in soil moisture cause the head to grow too quickly, exceeding the capacity of the outer leaves.
• How to fix/prevent it: Maintain consistent soil moisture through regular watering, 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: The extreme heat can stress Cabbage plants, making them more susceptible to pests and diseases. Sunscald can also be an issue, so consider providing afternoon shade with shade cloth during the hottest months. Our alkaline soil can also affect nutrient availability, so amend the soil with compost and other organic matter. The monsoon season, while welcome, can lead to splitting if watering isn't carefully managed.

Companion planting can help your Cabbage thrive in our Desert Southwest gardens. Green beans fix nitrogen in the soil, benefiting Cabbage's growth. Celery deters cabbage white butterflies. Onions repel many common pests. Potatoes don't directly benefit Cabbage, but they 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 stunt the growth of Cabbage. Strawberries are susceptible to similar fungal diseases as Cabbage, increasing the risk of infection.