Collard Greens in Zone 5B — Mountain West

Collard Greens thrive in the Mountain West, offering a slightly bitter, earthy flavor that complements our high-altitude meals. Their hearty texture holds up well in soups and stews, and the cool nights even in summer seem to intensify their sweetness. Growing your own means you'll have fresh greens long after the grocery store's supply starts looking sad.

While our short season and intense sun can pose challenges, careful timing and a little protection will see you through. Our 149-day growing season is just long enough to get a good harvest, especially if you take advantage of the late spring and early fall.

Starting Collard Greens indoors is an option, especially if you're eager to get a head start on the season. Aim to sow seeds indoors from late March through late April, about four weeks before you intend to transplant. This gives them a jump while the ground is still cold.

Use seed trays with a good seed-starting mix, and provide warmth (around 70°F) and plenty of light – a grow light is ideal. Bottom watering helps prevent damping off. Keep in mind that our late spring means you'll need to be patient and watch the weather closely before transplanting.

Transplant your Collard Greens seedlings outdoors from early May through early June, after the danger of hard frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the intense sun and cooler nights.

Space plants 18-24 inches apart in well-drained soil. Keep an eye on the forecast for late frosts, and be prepared to cover your transplants if needed. Our spring weather can be unpredictable!

Direct sowing Collard Greens is a straightforward method, especially if you have well-prepared soil. Sow seeds from late April through early July, once the soil temperature reaches at least 60°F. Direct sowing avoids transplant shock, but it does mean the plants are more vulnerable to early-season pests.

Prepare the soil by loosening it and adding compost. Sow seeds ½ inch deep and space them 18-24 inches apart. Thin seedlings as needed once they emerge. Watch out for slugs and snails, which can be a problem for young plants.

Collard Greens need consistent moisture to produce tender, flavorful leaves, but they don't like to be waterlogged. In our dry Mountain climate, regular watering is essential, especially during the hottest part of the summer. Even though they're more heat-tolerant than some other brassicas, they still appreciate consistent hydration.

During the spring and fall, when temperatures are cooler, water deeply once or twice a week, providing about 1 inch of water each time. In the heat of summer, increase watering to 2-3 times per week, ensuring the soil stays consistently moist. Use the finger test – if the top 2 inches of soil feel dry, it's time to water.

Water at the base of the plants to avoid wetting the leaves, as this can encourage fungal diseases. Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. Mulching around your plants with straw or wood chips helps retain moisture and regulate soil temperature, which is especially helpful in our intense sun.

You can expect your first harvest of Collard Greens from early July through early October, depending on when you planted. Look for lower leaves that are 10-12 inches long and a deep green color. These are usually the most mature and flavorful.

To harvest, simply snip off the outer leaves near the base of the plant, leaving the top rosette intact. This allows the plant to continue producing new leaves throughout the season. Collard Greens are known to sweeten in flavor after a light frost, so don't be afraid to leave them in the garden as late as possible.

As the first frost approaches in early October, harvest any remaining large leaves. You can blanch and freeze them for later use, or add them to soups and stews for a taste of summer.

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. You might also see white butterflies fluttering around.
• What causes it: Larvae of white cabbage butterflies. They can have multiple generations in our warmer months.
• How to fix/prevent it: Bt spray is very effective. Floating row covers will prevent the butterflies from laying eggs. Handpick the caterpillars when you see them. Attract parasitic wasps by planting dill and other herbs.

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 warmer weather. Ants may even farm them!
• How to fix/prevent it: A strong spray of water can knock them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap works well, and neem oil is systemic. Avoid excess nitrogen fertilizer.

Cabbage Loopers

• What it looks like: Pale green caterpillars that move in a looping motion. They chew large, ragged holes in leaves, often leaving the veins intact.
• What causes it: Similar to cabbage worms, these are the larvae of moths. They thrive in warm conditions.
• How to fix/prevent it: Handpicking is effective for small infestations. Bt spray is also a good option. Row covers can prevent moths from laying eggs on the plants.

Downy Mildew

• What it looks like: Yellow patches on leaf tops, with fuzzy gray-purple growth on the undersides. Leaves brown and die from the bottom up.
• What causes it: A pathogen that spreads in cool, humid conditions via wind-carried spores.
• How to fix/prevent it: Remove affected leaves immediately. Improve air circulation around plants. Water at the base, not overhead. Copper-based fungicides can help prevent it.

Mountain West Specific Challenges: Our moderate-at-altitude heat and low humidity can actually be beneficial, reducing the risk of some fungal diseases. However, the dry climate means consistent watering is crucial to keep plants healthy and productive. Hail can also damage leaves, so consider using netting if hail is frequent in your area.

Companion planting can help your Collard Greens thrive. Onions and garlic are great companions because their strong scent deters pests like cabbage moths and aphids. Beets improve soil health and nutrient availability, which benefits the Collard Greens. Potatoes can act as a trap crop for certain pests, drawing them away from your greens. Dill attracts beneficial insects like ladybugs and lacewings, which prey on aphids and other pests.

Avoid planting strawberries or tomatoes near Collard Greens. Strawberries are susceptible to similar fungal diseases, which can spread to the greens. Tomatoes can stunt the growth of Collard Greens, possibly due to allelopathic chemicals they release into the soil.