Collard Greens in Zone 6A — Mountain West

Collard greens are a fantastic addition to any Mountain West garden. Their slightly bitter flavor mellows with cooking, and they're incredibly versatile – use them in soups, stews, or braised as a side dish. Plus, they're remarkably cold-hardy, and the cool nights even in summer here in our high-altitude climate actually improve their flavor!

Our short growing season and alkaline soil can be challenges, but collards are surprisingly adaptable. With a 153-day growing season, you'll find that getting your timing right opens you up to a rewarding harvest.

Starting collard greens indoors is an option, especially if you're aiming for an early harvest. Starting seeds indoors from late March through mid April gives you a head start on our short season. This is about 4 weeks before you’d want to transplant them outside.

Use seed trays or small pots filled with a good seed-starting mix. Keep them consistently moist – bottom watering works well to avoid damping off. You'll also need a warm spot and plenty of light, either from a sunny window or a grow light. Remember, our spring weather can be unpredictable, so starting indoors gives you more control.

Transplanting your collard greens seedlings outdoors should happen early to late May. Before you plant them in the garden, it's crucial to harden them off. This means gradually exposing them to outdoor conditions for about a week to prevent shock.

Choose a spot with full sun to partial shade and space the seedlings 18-24 inches apart. Keep an eye on the forecast for late frosts – our Mountain springs are known for temperature swings, and you might need to cover them if a cold snap threatens.

Direct sowing is another viable option for collard greens. You can direct sow from mid April through early July. The benefit is less handling of the seedlings.

Prepare the soil by loosening it and adding compost to improve drainage and fertility. Ensure the soil temperature is at least 50°F (10°C) for good germination. Plant seeds about ½ inch deep and space them 18-24 inches apart. Keep the soil consistently moist until the seedlings emerge.

Watering collard greens properly is key to getting tender, flavorful leaves, especially with our dry climate. While collards are more heat-tolerant than some other brassicas, they still need consistent moisture, and we don't get much natural help from rainfall here in the Mountain West.

During the warmer months, from mid-June through August, aim to water deeply about 1-2 times per week, providing roughly 1-1.5 inches of water each time. 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 rather than overhead to minimize fungal issues in our low-humidity environment.

Signs of underwatering include wilting leaves and stunted growth. Overwatering, on the other hand, can lead to root rot, indicated by yellowing leaves and a generally unhealthy appearance. Adding a layer of mulch around your plants helps retain moisture and regulate soil temperature, which is especially helpful with our intense sun.

You can expect your first harvest of collard greens from early July through early October, about 75 days after planting. Look for the lower leaves to be about 10-12 inches long. These are ready to harvest.

To harvest, simply cut or snap off the outer, older leaves, leaving the central rosette intact. This allows the plant to continue producing throughout the season. Regular harvesting encourages more growth. Here in the Mountain West, the flavor of collard greens actually sweetens after a light frost, so don't be afraid to leave them in the garden as the weather cools.

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

Here are some common problems you might encounter with collard greens in the Mountain West:

Cabbage Worms

• What it looks like: Smooth green caterpillars chewing irregular holes in leaves. You'll also see dark green droppings and white butterflies fluttering around.
• What causes it: The larvae of those white cabbage butterflies. They can go through multiple generations in a season.
• How to fix/prevent it: Bt spray is very effective. Floating row covers will prevent the butterflies from laying eggs. Handpick the caterpillars and interplant with aromatic herbs like thyme and sage.

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: These sap-sucking insects reproduce rapidly, especially in warm weather.
• How to fix/prevent it: A strong spray of water can knock them off. Encourage ladybugs and lacewings. Use insecticidal soap for heavy infestations. Avoid excess nitrogen fertilizer.

Cabbage Loopers

• What it looks like: Similar to cabbage worms, but these are light green caterpillars that move in a looping motion. They also chew holes in leaves.
• What causes it: These are the larvae of moths. They can be especially troublesome in warmer parts of our region.
• How to fix/prevent it: The same controls that work for cabbage worms (Bt, row covers, handpicking) are effective against cabbage loopers.

Downy Mildew

• What it looks like: Yellow patches on leaf tops with fuzzy gray-purple growth on undersides. Leaves brown and die from the bottom up.
• What causes it: An oomycete pathogen that spreads in cool, humid conditions.
• How to fix/prevent it: Remove affected leaves immediately. Improve air circulation. Water at the base. Copper-based fungicides can help prevent it.

Mountain West Specific Challenges: Our intense sun can sometimes stress plants, making them more susceptible to pests and diseases. The alkaline soil can also affect nutrient availability. Be sure to amend your soil with plenty of organic matter to improve drainage and nutrient uptake.

Companion planting can be really helpful in the Mountain West.

• Onions and Garlic: These repel many common pests that bother collard greens.
• Beets: They help loosen the soil and don't compete for the same nutrients.
• Potatoes: They attract beneficial insects that prey on collard green pests.
• Dill: It attracts beneficial insects like ladybugs and hoverflies, which are natural predators of aphids and other pests.

Avoid planting collard greens near:

• Strawberries: They can attract slugs and snails that will also feed on your collard greens.
• Tomatoes: Both plants are susceptible to similar diseases, so planting them together can increase the risk of infection.