Mustard Greens in Zone 6B — Mid-Atlantic

Mustard greens bring a spicy kick to your Mid-Atlantic garden and kitchen. These greens thrive in our four-season climate, offering a quick and easy crop for both spring and fall harvests. The slightly peppery flavor adds a delicious dimension to salads, stir-fries, and braised dishes, making them a versatile addition to your homegrown meals.

While our humid summers and occasional deer pressure can present challenges, careful timing and a few simple strategies will ensure a bountiful harvest of mustard greens. Our 198-day growing season gives you ample opportunity to enjoy this flavorful leafy green.

Starting mustard greens indoors in the Mid-Atlantic is definitely possible, but honestly, it's not always necessary. If you're itching to get a head start, you can sow seeds indoors from late February through mid March, about three weeks before the last expected frost. This can be helpful if you want an extra-early crop.

Use seed trays or small pots filled with a good seed-starting mix. Keep them warm (around 70°F) and provide plenty of light, either with a grow light or a sunny windowsill. I recommend bottom watering to keep the soil consistently moist without damping off. Our moderate spring weather usually allows for direct sowing, but starting indoors gives you a jump!

Transplanting mustard greens outdoors in the Mid-Atlantic should happen from late March through early May. Before you put those seedlings in the ground, be sure to harden them off. Give them about a week of gradual exposure to the outdoors, increasing the time spent outside each day.

Space your plants about 6-12 inches apart in well-drained soil. Keep an eye on the weather forecast – we can still get some unexpected cold snaps in early spring, so be ready to cover your transplants if needed.

Direct sowing mustard greens is a great option in the Mid-Atlantic, and it's my preferred method. You can start sowing seeds directly into the garden from mid March through late August, giving you plenty of opportunities for multiple harvests.

Make sure the soil is loose and well-worked. Sow seeds about ½ inch deep and space them 6-12 inches apart. Keep the soil consistently moist until the seedlings emerge. Direct sowing is a great way to avoid transplant shock, and it's generally less work.

Watering is crucial for happy mustard greens in our Mid-Atlantic climate. While we get fairly even rainfall, our humid summers can still lead to drought stress if you're not careful. Consistent moisture is key, as drought stress will make the leaves spicier and can even trigger bolting.

During the spring and fall, when temperatures are milder, you might only need to water once or twice a week, depending on rainfall. During the summer heat, especially in July and August, you'll likely need to water every other day, or even daily if it's particularly hot and dry. Stick your finger about two inches into the soil – if it feels dry, it's time to water. Aim for about an inch of water per week, whether from rain or irrigation.

Water at the base of the plants to avoid wetting the leaves, especially in our humid climate. This helps prevent fungal diseases. Signs of underwatering include wilting leaves and slow growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch around your plants helps retain moisture and keeps the soil cool, which is especially helpful during those moderate-to-hot summer months.

You can expect your first harvest of mustard greens in the Mid-Atlantic from late April through early November, depending on when you planted. Mustard greens are usually ready to harvest about 45 days after planting. Young leaves will have a milder flavor, while larger leaves will be spicier.

Harvest by snipping off the outer leaves, leaving the inner leaves to continue growing. This cut-and-come-again method allows for continuous production throughout the season. Be sure to harvest before the plants start to flower (bolt), as the leaves will become bitter once they bolt.

As our first frost approaches in late October, harvest any remaining leaves to enjoy before the cold weather sets in. You might even get a few more harvests if you cover the plants with a cold frame or row cover to protect them from frost.

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, especially on young seedlings. You might also see small dark beetles that jump when disturbed.
• What causes it: Small jumping beetles that feed on the leaves. They're most damaging to small, young plants.
• How to fix/prevent it: Use row covers to protect seedlings during their vulnerable stage. You can also delay planting until plants are larger and more resilient. A coating of kaolin clay can deter them. Neem oil spray can also help. Interplanting with basil or catnip may help repel 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: These sap-sucking insects reproduce rapidly, especially in warm weather. Ant colonies may farm 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 can be used for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer, as it attracts them.

Cabbage Worms

• What it looks like: Smooth green caterpillars on the leaves. Irregular holes chewed in the leaves, dark green droppings, and white butterflies hovering around the plants.
• What causes it: These are the larvae of those white cabbage butterflies. We often get multiple generations per season with our moderate-to-hot summers.
• How to fix/prevent it: Bt spray is very effective. Floating row covers can prevent the butterflies from laying eggs. You can also handpick the caterpillars. Interplant with aromatic herbs like thyme and sage.

Bolting in Heat

• What it looks like: The plant sends up a flower stalk, and the leaves become tough and bitter.
• What causes it: Mustard greens are a cool-season crop, and they'll bolt when temperatures rise. This is more likely to happen when temperatures consistently exceed 80°F.
• How to fix/prevent it: Time your plantings for cool weather in the spring and fall. Choose bolt-resistant varieties. Provide shade during warm spells. Mulch to keep the soil cool. Harvest leaves before bolting progresses too far.

Mid-Atlantic Specific Challenges: Our humid summers can increase the risk of fungal diseases, so proper spacing and watering at the base of the plants are important. Deer pressure can also be a concern, so consider fencing or deer-resistant strategies.

Companion planting can really help your mustard greens thrive here in the Mid-Atlantic.

Good companions include:

• Onion and garlic: These alliums deter pests like aphids and flea beetles.
• Beets: They don't compete for nutrients and can help loosen the soil.
• Dill: Attracts beneficial insects like ladybugs and lacewings, which prey on aphids.
• Lettuce: Provides ground cover, helping to retain moisture and suppress weeds.

Avoid planting mustard greens near:

• Strawberries: Mustard greens can inhibit strawberry growth.
• Tomatoes: They compete for the same nutrients and are susceptible to similar pests and diseases.