Collard Greens in Zone 5A — Great Plains

Collard greens offer a unique, slightly bitter flavor that's fantastic in soups, stews, or simply sautéed. In the Great Plains, they're a rewarding crop, thriving in our intense sunshine and offering a delicious harvest that extends well into the cooler months. Plus, their upright habit fits nicely in smaller gardens, and fresh greens always beat the grocery store.

Don't let our extreme weather scare you off! The Plains throws everything at us – wind, hail, temperature swings. By planting at the right time and providing some protection, you can enjoy a great collard crop within our 168-day growing season.

Starting collards indoors can give you a jump start, especially if you are further north in the Plains with a shorter growing season. Begin in late March through mid April, roughly four weeks before you plan to transplant. Use seed trays with a good seed-starting mix and keep them consistently moist – bottom watering works well to prevent damping off.

Place the trays in a warm location with plenty of light, either a sunny windowsill or under grow lights. Remember, our spring weather is variable, so indoor starting gives you control during those unpredictable temperature swings.

Transplant your collard seedlings outdoors in late April through late May. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the wind and temperature fluctuations common in the Plains.

Space plants 18-24 inches apart to allow for good air circulation and growth. Be mindful of late frosts; keep an eye on the forecast and be prepared to cover your seedlings if necessary.

Direct sowing collards is a simple and effective method, especially for later crops. Sow seeds mid April through mid July, when the soil has warmed up a bit. Aim for a soil temperature of around 60-70°F for best germination.

Prepare the soil by loosening it and adding compost. Plant seeds about ½ inch deep, spacing them 18-24 inches apart. Direct sowing is a great option if you want to stagger your harvest or if you're looking for a low-maintenance approach.

Consistent watering is key to growing tender, flavorful collard greens in the Great Plains. While collards are more heat-tolerant than many brassicas, our hot summers and variable rainfall mean they still need regular moisture. Aim for even moisture, as inconsistent watering can lead to tough, bitter leaves.

During the peak of summer, when temperatures soar into the 90s, check the soil moisture frequently. Stick your finger about two inches deep – if it feels dry, it's time to water. Typically, collards need about 1-1.5 inches of water per week, either from rainfall or irrigation. 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 good layer of mulch, such as straw or wood chips, helps retain moisture and regulate soil temperature, which is especially helpful during our extreme temperature swings.

You can expect your first harvest of collard greens in late June through mid October, about 75 days after planting. Look for lower leaves that are 10-12 inches long and a deep green color. Harvest these outer leaves by cutting them off near the base of the plant, leaving the top rosette intact for continued production.

This allows the plant to keep growing and producing new leaves throughout the season. Many gardeners in the Plains find that the flavor of collards actually sweetens after a light frost.

As the first frost approaches in early October, you can harvest the entire plant if you wish, or cover it to extend the harvest a bit longer. Collards are pretty hardy, but a hard freeze will eventually damage them.

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 the leaves. You might also see dark green droppings and white butterflies fluttering around.
• What causes it: These are the larvae of white cabbage butterflies. They thrive in our warm summers and can go through multiple generations.
• How to fix/prevent it: Use Bt spray, which is very effective. Floating row covers prevent butterflies from laying eggs. Handpick caterpillars when you see them. Interplant with aromatic herbs like thyme and sage to 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: Aphids are sap-sucking insects that reproduce rapidly, especially in warm weather. Ant colonies often "farm" them for their honeydew.
• How to fix/prevent it: A strong spray of water can knock them off. Encourage ladybugs and lacewings, which are natural predators. Use insecticidal soap for heavy infestations. Avoid over-fertilizing with nitrogen, as this attracts aphids.

Cabbage Loopers

• What it looks like: Similar to cabbage worms, but these caterpillars move in a looping motion. They also chew holes in the leaves.
• What causes it: Another type of caterpillar that loves brassicas. Like cabbage worms, they are more prevalent in warm weather.
• How to fix/prevent it: Use Bt spray or handpick them. Floating row covers can also help prevent them from reaching your 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 by spacing plants properly. Water at the base of the plants, never overhead. Copper-based fungicides can be used for prevention.

Great Plains Specific Challenges: The hot heat of our summers, combined with variable rainfall and low-to-moderate humidity, can stress collard greens. Wind protection is also essential to prevent leaf damage. Consistent watering and monitoring for pests are key to a successful harvest.

Companion planting can give your collard greens a boost in the Great Plains. Onions and garlic help deter pests with their strong scent. Beets and potatoes are good neighbors because they don't compete for the same nutrients. Dill attracts beneficial insects that prey on aphids and other pests.

Avoid planting collards near strawberries or tomatoes. Strawberries can attract slugs, which may also damage collards. Tomatoes can stunt the growth of collards, as they compete for similar resources.