Collard Greens in Zone 4B — Mountain West

Collard Greens might not be the first thing that comes to mind for your Mountain West garden, but these hardy greens thrive in our intense sunlight and actually get sweeter with our cool nights. Their robust flavor makes them a versatile addition to soups, stews, or even sauteed as a side dish, bringing a taste of the South right to your high-altitude kitchen.

We know our short 128-day growing season and alkaline soil present unique challenges, but with proper timing and a few tricks, you can successfully grow delicious Collard Greens. Starting at the right time is key, and we'll walk you through the best approach for our unpredictable Mountain weather.

Starting Collard Greens indoors gives you a head start on our short growing season, but it's not always necessary. If you're aiming for an earlier harvest or want to guarantee a strong start, sow seeds indoors from early April through early May, about four weeks before you plan to transplant.

Use seed trays with a good seed-starting mix, and keep them warm (around 70-75°F) until germination. A sunny windowsill or grow light provides the light they need. Bottom watering helps prevent damping off, a common issue with seedlings. Remember our late springs; don't be tempted to start too early!

Transplant your Collard Greens seedlings outdoors from mid May through mid June, after the danger of hard frost has passed. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week.

Choose a spot with full sun to partial shade and space the plants 18-24 inches apart. Even in late spring, our intense UV can stress young plants, so provide temporary shade if needed. A sudden hailstorm can also decimate young plants, so be prepared to cover them if necessary.

Direct sowing Collard Greens is a viable option in our region, especially if you're not aiming for a super early harvest. Sow seeds directly into the garden from early May through late June.

Ensure the soil is well-worked and at least 60°F. Plant seeds ½ inch deep, spacing them 18-24 inches apart. Keep the soil consistently moist until germination. Direct sowing avoids transplant shock, but remember that you're at the mercy of our sometimes unpredictable spring weather.

Watering Collard Greens correctly is crucial in our dry Mountain West climate. While more heat-tolerant than some other brassicas, they still need consistent moisture, especially to produce tender leaves. Aim for about 1-1.5 inches of water per week, more during heat waves.

In early spring, when temperatures are cooler, you may only need to water once or twice a week. As summer heats up, increase watering frequency to every other day, or even daily during hot spells. Use the "finger test"—stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. Water deeply at the base of the plants, avoiding overhead watering, which can lead to fungal issues in some years, though our low humidity usually keeps this in check.

Signs of underwatering include wilting leaves and slow growth. Overwatering can cause yellowing leaves and root rot. Mulching around your Collard Greens with straw or wood chips helps retain moisture and regulate soil temperature, which is especially beneficial with our intense sun.

You can expect your first harvest of Collard Greens from mid July through late September, about 75 days after planting. Start harvesting the lower leaves when they are 10-12 inches long.

Harvest by cutting or snapping off the outer leaves, leaving the central rosette intact. This allows the plant to continue producing new leaves throughout the season. Many gardeners in our region find that the flavor of Collard Greens sweetens after a light frost, so don't be afraid to leave them in the garden as long as possible.

As our first frost approaches in mid- September, harvest any remaining mature leaves. While Collard Greens are frost-hardy, a hard freeze can damage the 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, with dark green droppings. White butterflies fluttering nearby.
• What causes it: Larvae of white cabbage butterflies. While we don't have multiple generations like warmer climates, they can still be a nuisance.
• How to fix/prevent it: Bt spray is very effective. Floating row covers prevent egg laying. Handpick caterpillars. Interplant with aromatic herbs.

Aphids

• What it looks like: Clusters of tiny insects (green, black, or white) on stems and leaf undersides. Sticky honeydew. Curled or distorted new growth.
• What causes it: Rapidly reproducing sap-sucking insects. Populations can explode quickly, even in our dry climate.
• How to fix/prevent it: Strong water spray. Encourage ladybugs and lacewings. Insecticidal soap for heavy infestations. Avoid excess nitrogen fertilizer.

Cabbage Loopers

• What it looks like: Similar to cabbage worms, but these caterpillars move in a looping motion. They also chew holes in leaves.
• What causes it: Another type of caterpillar that feeds on brassicas.
• How to fix/prevent it: Bt spray is effective. Handpick caterpillars. Floating row covers can help.

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: Oomycete pathogen that spreads in cool, humid conditions. While our humidity is low, cool nights and occasional wet spells can create favorable conditions.
• How to fix/prevent it: Remove affected leaves. Improve air circulation. Water at the base. Copper-based fungicides for prevention.

Mountain West Specific Challenges: Our intense UV can stress plants, making them more susceptible to pests and diseases. Our dry climate means you'll need to be diligent about watering. Even with low humidity, downy mildew can still occur, especially during cool, wet springs. Alkaline soil can also affect nutrient uptake, so amend your soil with compost before planting. Hail is always a threat, so be prepared to cover your plants if a storm is brewing.

Companion planting can enhance your Collard Greens' growth in our Mountain West gardens.

• Good companions:
• Onion and Garlic: These alliums deter pests like aphids and cabbage worms.
• Beets: They don't compete for nutrients and can help loosen the soil.
• Potatoes: They don't compete for the same resources and can provide some shade.
• Dill: Attracts beneficial insects like ladybugs and lacewings, which prey on aphids.
• Bad companions:
• Strawberry: Collard Greens can inhibit strawberry growth.
• Tomato: They compete for nutrients and can attract similar pests.