Mustard Greens in Zone 6A — Midwest

Mustard greens are a fantastic addition to your Midwest garden, offering a peppery kick to salads and cooked dishes. They thrive in our fertile soil and provide a welcome burst of flavor during the cooler parts of our growing season. Plus, there's nothing quite like the satisfaction of harvesting your own greens when the weather is just right.

While Midwest weather can be unpredictable, especially with those summer heat spells, mustard greens are quick to mature. By timing your plantings carefully, you can enjoy multiple harvests within our 178-day growing season. It's all about working *with* the seasons, not against them.

Starting mustard greens indoors is an option, especially if you're eager to get a very early start. Begin in early to late March, about three weeks before you plan to transplant. This gives them a head start, but honestly, mustard greens grow so quickly that direct sowing is often preferred in our region.

Use seed trays or small pots filled with a good seed-starting mix. Keep them warm and provide plenty of light – a grow light works wonders. Water from the bottom to encourage strong root growth and prevent damping off. Remember, our springs can be variable, so indoor starting provides some insurance against late frosts.

Transplant your mustard greens seedlings outdoors from early April through mid May, once the soil has warmed up a bit. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Space the plants 6-12 inches apart to give them room to grow. Keep an eye on the weather forecast – a late frost can still happen, so be prepared to cover them if necessary. Our springs can be wet, so ensure good drainage to prevent root rot.

Direct sowing is a popular method for mustard greens in the Midwest, and honestly, it's usually the easiest. Sow seeds from late March through mid August for a continuous harvest. The key is to ensure the soil temperature is consistently above 45°F.

Prepare the soil by loosening it and adding compost for good drainage. Plant seeds about ½ inch deep and space them 6-12 inches apart. Thin seedlings as needed to give them adequate room. Direct sowing works well because our summers provide good heat for quick germination, but remember to keep the soil consistently moist.

Mustard greens need consistent moisture to thrive in our Midwest climate. While we often get decent summer rainfall, it's important to pay attention to the specific needs of your plants. Aim to keep the soil consistently moist, but not waterlogged.

A good way to check is the "finger test": stick your finger about 2 inches into the soil. If it feels dry, it's time to water. In general, aim for about 1 inch of water per week, whether from rain or irrigation. During those summer heat spells, you might need to water more frequently.

Water at the base of the plants to avoid wetting the leaves, which can increase the risk of fungal diseases, especially with our moderate-to-humid conditions. Overwatering can lead to yellowing leaves, while underwatering can cause the leaves to become tougher and more bitter, and can trigger bolting. A layer of mulch, like straw or shredded leaves, can help retain moisture and regulate soil temperature, beneficial for our variable Midwest weather.

You can expect your first harvest of mustard greens from early May through late October, depending on when you planted. Mustard greens are typically ready to harvest about 45 days after planting. Look for leaves that are a good size, but still tender.

Harvest young leaves for a milder flavor and larger leaves for a spicier kick. Pick the outer leaves, leaving the inner ones to continue growing. This encourages continued production throughout the season. Be sure to harvest before the plants start to flower, as this will cause the leaves to become bitter.

As our first frost approaches in mid- October, harvest any remaining leaves to enjoy. You can also cover the plants with a frost blanket to extend the harvest a bit longer, but don't expect miracles – mustard greens are semi-hardy, not invincible.

Here are some common problems you might encounter with mustard greens in the Midwest:

Flea Beetles

• What it looks like: Tiny round holes (shot-hole pattern) in the leaves. You'll see small dark beetles that jump when disturbed.
• What causes it: These small jumping beetles feed on the leaves, especially damaging to young seedlings. They thrive in the warm, dry conditions that can occur in our Midwest summers.
• How to fix/prevent it: Use row covers to protect seedlings during their vulnerable stage. Delay planting until plants are larger. You can also try kaolin clay coating or neem oil spray. Interplanting with basil or catnip can help deter them.

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. You might also notice a sticky honeydew residue or curled and distorted new growth.
• What causes it: Aphids are sap-sucking insects that reproduce rapidly, especially in warm weather. Ant colonies may farm them for honeydew.
• How to fix/prevent it: A strong water spray can knock them off. Encourage natural predators like ladybugs and lacewings. For heavy infestations, use insecticidal soap or neem oil. Avoid excess nitrogen fertilizer, as it attracts them.

Cabbage Worms

• What it looks like: Smooth green caterpillars on the leaves, with irregular holes chewed in them. You might also see dark green droppings and white butterflies hovering around the plants.
• What causes it: These are the larvae of white cabbage butterflies. They can have multiple generations per season in our warm climate.
• How to fix/prevent it: Bt spray is very effective. Use floating row covers to prevent egg laying. Handpick caterpillars when you see them. Interplant with aromatic herbs like thyme and sage to deter the butterflies.

Bolting in Heat

• What it looks like: The plant sends up a flower stalk, and the leaves become tough and bitter.
• What causes it: Bolting occurs when this cool-season crop experiences extended warm temperatures. Brassicas bolt when days consistently exceed 80°F, which can happen during our summer heat spells.
• How to fix/prevent it: Time your plantings for cool weather in spring and fall. Choose bolt-resistant varieties. Provide shade during warm spells. Mulch to keep the soil cool. Harvest before bolting progresses.

Midwest Specific Challenges: Our moderate-to-hot summers and moderate-to-humid conditions can create a favorable environment for pests and diseases. The wet-summer rainfall can also lead to overwatering if you're not careful. Pay close attention to your plants and adjust your watering and pest control strategies as needed.

Companion planting can be a great way to improve the health and productivity of your mustard greens in the Midwest garden.

Good companions include onions and garlic, as their strong scent can deter pests like aphids and flea beetles. Beets are also a good choice, as they don't compete for the same nutrients and can help loosen the soil. Dill attracts beneficial insects that prey on pests. Lettuce can provide ground cover, helping to keep the soil cool and moist.

Avoid planting mustard greens near strawberries or tomatoes. Strawberries are susceptible to some of the same fungal diseases as mustard greens, increasing the risk of infection. Tomatoes can stunt the growth of mustard greens, as they compete for the same nutrients and resources in our fertile soil.