Mustard Greens in Zone 6A — Mid-Atlantic

Mustard greens are a fantastic addition to any Mid-Atlantic garden, offering a spicy kick to salads, stir-fries, and braised dishes. Their peppery flavor is especially welcome during our four seasons, adding zest to meals from early spring harvests to late fall side dishes. Plus, they're quick to mature, so you can enjoy fresh greens in no time.

We Mid-Atlantic gardeners know our humid summers and sometimes unpredictable spring weather can be tricky. But with proper timing, mustard greens thrive here. Our 188-day growing season provides ample opportunity for multiple plantings, ensuring a steady supply of these flavorful greens.

While mustard greens do wonderfully when direct sown, starting them indoors gives you a head start, especially for an early spring harvest. Start seeds indoors from early to late March, about three weeks before you plan to transplant. Use seed trays with a good seed-starting mix, and keep them warm and under grow lights.

Bottom watering is key to prevent damping off. Just set the tray in a shallow dish of water until the top of the soil is moist. Given our moderate spring, starting indoors can help you get a jump on the season, but it's not essential.

Transplant your mustard green seedlings outdoors from early April through mid May. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Mid-Atlantic's variable spring weather.

Space plants 6-12 inches apart in well-drained soil. Watch out for late frosts, which can still occur in early April. Row covers can provide extra protection if needed.

Direct sowing mustard greens is easy and effective in our Mid-Atlantic climate. Sow seeds from mid March through late August for a continuous harvest. Choose a spot with full sun to partial shade, and prepare the soil by loosening it and adding compost.

Sow seeds 1/4 inch deep, spacing them 6-12 inches apart. Keep the soil consistently moist until germination. Direct sowing is a great option for successive plantings throughout the growing season, allowing you to enjoy fresh greens well into the fall.

Mustard greens need consistent moisture, especially during our humid summers. Aim to keep the soil evenly moist, but not waterlogged. A good rule of thumb is to water deeply when the top two inches of soil feel dry to the touch – that's the "finger test."

During the hotter months, your mustard greens will likely need about 1 inch 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 humid climate. Signs of underwatering include wilting leaves and a bitter taste, while overwatering can lead to yellowing leaves and root rot.

Mulching around your plants with straw or shredded leaves helps retain moisture and suppress weeds. This is especially beneficial in our region, where the combination of heat and humidity can quickly dry out the soil.

You can expect your first harvest of mustard greens from early May through late October, about 45 days after planting. Harvest young leaves for a milder flavor, or wait until the leaves are larger for a spicier kick. The flavor intensifies with size.

Harvest by snipping off individual leaves from the outer part of the plant, leaving the center to continue growing. This allows for continuous harvesting throughout the season. Be sure to harvest before the plant starts to flower (bolt), as the leaves will become tough and bitter.

As our first frost approaches in mid- October, you can extend your harvest by covering the plants with a cold frame or row cover. This will protect them from the frost and allow you to enjoy fresh greens a bit longer.

Here are some common problems you might encounter with mustard greens in the Mid-Atlantic:

Flea Beetles

• What it looks like: Tiny round holes (shot-hole pattern) in leaves. You might see small, dark beetles that jump when disturbed.
• What causes it: Small jumping beetles that feed on leaves. They're most damaging to small, young plants.
• How to fix/prevent it: Use row covers to protect seedlings. You can also delay planting until plants are larger and stronger. Coating the leaves with kaolin clay can deter them, as can spraying with neem oil. Interplanting with basil or catnip may help.

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. You might also see sticky honeydew residue and curled or distorted new growth.
• What causes it: These are rapid-reproducing sap-sucking insects. Populations explode in our warm weather. Ant colonies may farm them for honeydew.
• How to fix/prevent it: A strong spray of water can knock them off. Encourage ladybugs and lacewings (natural predators). Use insecticidal soap for heavy infestations, or neem oil, which works systemically. 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 the leaves. 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. We can have multiple generations per season in our warm climate.
• How to fix/prevent it: Bt spray is very effective. Floating row covers prevent egg laying. Handpick caterpillars when you see them. Interplant with aromatic herbs like thyme and sage, and encourage parasitic wasps.

Bolting in Heat

• What it looks like: The plant sends up a flower stalk, and the leaves become tough and bitter.
• What causes it: Extended warm temperatures above the crop's comfort zone. Mustard greens bolt when days consistently exceed 80°F.
• How to fix/prevent it: Time your plantings for cooler weather in spring and fall. Choose bolt-resistant varieties. Provide shade during warm spells. Mulch to keep the soil cool. Harvest before bolting progresses too far.

Mid-Atlantic Specific Challenges: Our moderate-to-hot summers and humid humidity can make mustard greens more susceptible to bolting and fungal diseases. Consistent watering and good air circulation are essential. Also, be vigilant about pests, as they can thrive in our climate.

Mustard greens benefit from companion planting. Onions and garlic help deter pests with their strong scent. Beets are good neighbors as they don't compete for the same nutrients. Dill attracts beneficial insects that prey on pests, while lettuce provides ground cover, keeping the soil cool and moist.

Avoid planting mustard greens near strawberries or tomatoes. Strawberries are susceptible to some of the same fungal diseases, and tomatoes can attract pests that also affect mustard greens. Keeping them separated reduces the risk of problems in your Mid-Atlantic garden.