Collard Greens in Zone 9A — Desert Southwest

Collard greens are a Southern staple that surprisingly thrives in our Desert Southwest gardens. Their slightly bitter, earthy flavor is delicious braised, sautéed, or added to soups, and they're packed with nutrients. Plus, the satisfaction of harvesting your own greens, especially during our mild winters, is hard to beat.

Don't let our extreme heat scare you away. While summer survival is a challenge, our two growing seasons and long fall give you ample time to enjoy a good harvest. With careful timing and a little planning, you can absolutely grow collard greens here in Zone 9A.

Starting collard greens indoors gives you a head start, especially for the spring growing season. Sow seeds indoors from mid January through early February, about four weeks before you plan to transplant them. Use seed trays with a good seed-starting mix, and keep them consistently moist – bottom watering works great to avoid damping off.

Place the trays in a warm location with plenty of light; a sunny windowsill or grow lights work well. Given our very-early spring character here in the Desert Southwest, this indoor jump can be a real advantage.

Transplant your collard greens seedlings outdoors from mid February through mid March. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the intense Desert Southwest sun and temperature fluctuations.

Space the seedlings 18-24 inches apart in well-draining soil. Keep in mind that even in February and March, we can experience unexpected warm spells, so keep an eye on the forecast and provide shade cloth if needed.

Direct sowing collard greens is a viable option, especially for a fall harvest. Sow seeds directly into the garden from early February through mid September. Ensure the soil is well-prepared and consistently moist until germination.

Thin the seedlings to 18-24 inches apart once they are a few inches tall. Direct sowing is less work initially, but you'll need to be diligent about watering, especially during the hotter months, to ensure successful germination and growth.

Collard greens need consistent moisture to produce tender, flavorful leaves, but avoid soaking them. During the hot summer months, you'll likely need to water deeply several times a week, possibly even daily, depending on your soil. In the cooler spring and fall, watering every few days might suffice.

Stick your finger about two inches deep into the soil to check the moisture level. If it feels dry, it's time to water. Aim for about 1-2 inches of water per week, adjusting based on rainfall and temperature. Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases, even in our arid climate.

Underwatering results in wilted, yellowing leaves, while overwatering can lead to root rot. Applying a layer of organic mulch, like shredded leaves or straw, will help retain moisture and regulate soil temperature, which is critical for summer survival.

You can expect your first harvest of collard greens from mid April through mid December, about 75 days after planting. Harvest the lower leaves when they reach 10-12 inches in length. These are usually the oldest leaves.

Simply snap or cut the leaves off near the base of the plant, being careful not to damage the main stem. Leaving the top rosette intact allows the plant to continue producing new leaves for a continuous harvest. Many gardeners find that the flavor of collard greens sweetens after a light frost.

As the first frost approaches in early December, harvest any remaining large leaves. You can also cover the plants with a frost blanket to extend the harvest a bit longer.

Here are common problems you might face growing collard greens in the Desert Southwest:

Cabbage Worms *What it looks like:* Smooth green caterpillars chewing irregular holes in leaves, leaving dark green droppings. You might see white butterflies fluttering nearby. *What causes it:* Larvae of white cabbage butterflies. Multiple generations can occur in our long warm season. *How to fix/prevent it:* Bt spray is very effective and safe. Use floating row covers to prevent butterflies from laying eggs. Handpick caterpillars whenever you spot them.

Aphids *What it looks like:* Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue and curled or distorted new growth. *What causes it:* Rapidly reproducing sap-sucking insects that thrive in warm weather. *How to fix/prevent it:* Knock them off with a strong water spray. Encourage ladybugs and lacewings. Use insecticidal soap or neem oil for heavy infestations.

Cabbage Loopers *What it looks like:* Pale green caterpillars that move in a looping motion, chewing holes in leaves. Similar damage to cabbage worms. *What causes it:* Larvae of moths. They can be difficult to spot due to their camouflage. *How to fix/prevent it:* Similar to cabbage worms, use Bt spray, handpick, and use row covers. Regularly inspect plants for early signs of infestation.

Downy Mildew *What it looks like:* Yellow patches on leaf tops with fuzzy gray-purple growth on undersides. Leaves turn brown and die from the bottom up. *What causes it:* A fungal disease that spreads in cool, humid conditions. *How to fix/prevent it:* Remove affected leaves immediately. Improve air circulation by spacing plants properly. Water at the base of the plants. Copper-based fungicides can help prevent spread.

Desert Southwest Specific Challenges: The extreme heat and intense sun can stress collard greens, making them more susceptible to pests and diseases. The arid climate can also lead to rapid moisture loss, requiring diligent watering. Even with monsoon moisture, our alkaline soil can affect nutrient uptake, so amend with compost regularly.

Companion planting can really help your collard greens thrive. Onions and garlic are great companions because their strong scent deters many pests that bother collards. Beets also work well, as they don't compete for the same nutrients and can help loosen the soil.

Potatoes can be good companions, as they provide shade and help retain moisture in the soil. Dill attracts beneficial insects like ladybugs and lacewings, which prey on aphids and other pests. Avoid planting collard greens near strawberries or tomatoes, as they can attract similar pests and diseases, increasing the risk of problems.