Collard Greens in Zone 6A — Great Plains

Collard greens are a fantastic choice for the Zone 6A Great Plains garden. Their slightly bitter, earthy flavor mellows into something truly special when cooked, and they offer incredible versatility in the kitchen. Plus, they provide a satisfying harvest that extends well into the fall, even after a light frost sweetens their flavor.

Our Plains climate throws some curveballs with its extreme temperature swings, variable rainfall, and occasional hail. But don't worry, collards are surprisingly resilient, and with a little planning, you can enjoy a bountiful harvest within our roughly 188-day growing season.

Starting collard greens indoors is an option, especially if you're aiming for an early harvest or want a head start against potential pests. Begin in mid-March through early April, about four weeks before you plan to transplant. Use seed trays with a good seed-starting mix, ensuring they have adequate drainage.

Keep the trays in a warm location, ideally around 70-75°F, and provide plenty of light – a sunny windowsill or grow lights work well. Bottom watering is a great way to keep the soil consistently moist without overwatering; just set the tray in a shallow dish of water and let the soil soak it up. Remember that spring in the Plains can be unpredictable, so indoor starts provide a buffer against late frosts.

Transplant your collard green seedlings outdoors in mid-April through mid-May, once the danger of a hard frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. Start with an hour or two of sunlight and wind, increasing the time each day.

Plant them 18-24 inches apart in well-drained soil. Keep an eye on the weather forecast around transplant time; a sudden cold snap can stress young plants, so be prepared to cover them if necessary.

Direct sowing collard greens is a simple and effective method, especially if you have well-draining soil. Sow seeds directly into the garden from early April through late July. This gives you flexibility to plant multiple crops for a longer harvest window.

Prepare the soil by loosening it and removing any rocks or debris. Sow seeds about ½ inch deep and 18-24 inches apart. Keep the soil consistently moist until the seedlings emerge. Direct sowing avoids transplant shock, but young seedlings are more vulnerable to pests, so keep a close eye on them.

Consistent watering is key to growing tender, flavorful collard greens in our Great Plains climate. While collards are more heat-tolerant than some other brassicas, they still need regular moisture, especially during our hot summer months. A good rule of thumb is to water deeply about 1 inch per week, but adjust based on rainfall and soil conditions.

The "finger test" is your best friend: stick your finger into the soil about 2 inches deep. If it feels dry, it's time to water. During the hottest parts of summer, you might need to water more frequently, especially if you're experiencing a dry spell. Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our low-to-moderate humidity.

Signs of underwatering include wilting leaves and slow growth. Overwatering, on the other hand, can lead to yellowing leaves and root rot. A layer of mulch around your collard greens can help retain moisture and suppress weeds, which is especially beneficial during our variable rainfall patterns.

You can expect your first harvest of collard greens from mid-June through late October, about 75 days after planting. Look for the lower leaves to be 10-12 inches long and a healthy, deep green color. These mature leaves will be ready to pick.

To harvest, simply snap off the lower leaves, leaving the top rosette intact. This allows the plant to continue producing new leaves throughout the season. The flavor of collard greens actually sweetens after a light frost, so don't be afraid to leave them in the garden until the first frosts approach in mid- October.

As the end of the season nears, you can harvest the entire plant if you want to use up all the remaining leaves. Or, you can simply let the plant die back naturally, knowing you've enjoyed a long and bountiful harvest.

Here are some common problems you might encounter growing collard greens in the Great Plains:

Cabbage Worms

• What it looks like: Smooth green caterpillars chewing irregular holes in leaves, leaving dark green droppings. You might see white butterflies fluttering around.
• What causes it: These are the larvae of white cabbage butterflies. They thrive in our warm summer weather, going through multiple generations.
• How to fix/prevent it: Bt spray is very effective and safe for consumption after application. Floating row covers can prevent butterflies from laying eggs. Handpick caterpillars when you see them. Interplanting with aromatic herbs like thyme and sage can also deter 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: These sap-sucking insects reproduce rapidly, especially in warm weather. Ant colonies often protect them, farming them for honeydew.
• How to fix/prevent it: A strong spray of water can knock them off. Encourage natural predators like ladybugs and lacewings. Insecticidal soap is effective for heavy infestations. Neem oil also works well. Avoid over-fertilizing with nitrogen, as it attracts aphids.

Cabbage Loopers

• What it looks like: Similar to cabbage worms but move in a looping motion. They are pale green with white stripes.
• What causes it: Similar to cabbage worms, they are larvae of moths that lay eggs on the underside of leaves.
• How to fix/prevent it: Use row covers to prevent moths from laying eggs. Handpick loopers when you see them. Bt spray is also effective.

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: This is 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 the spread.

Great Plains Specific Challenges: Our region's hot summers can stress collard greens, making them more susceptible to pests and diseases. Variable rainfall means you need to be vigilant about watering. Wind can also damage leaves, so consider providing some wind protection, especially for young plants.

Companion planting can be a valuable tool for growing healthy collard greens in the Great Plains.

Good companions include onions and garlic, as their strong scent can deter pests like aphids and cabbage moths. Beets and potatoes are also beneficial, as they don't compete for the same nutrients and can help improve soil health. Dill attracts beneficial insects like ladybugs and lacewings, which prey on aphids and other pests.

Avoid planting collard greens near strawberries or tomatoes. Strawberries are susceptible to some of the same pests and diseases as collards, and tomatoes can stunt the growth of collards.