Mustard Greens in Zone 7B — Mid-Atlantic

Mustard greens are a fantastic addition to any Mid-Atlantic garden. Their peppery bite adds zest to salads and stir-fries, and they thrive in our four seasons, offering a delicious harvest from spring through fall. The satisfaction of growing your own greens, especially after a long winter, is hard to beat, and they are so much fresher than anything you'll find at the store.

While our humid summers and occasional deer pressure can pose challenges, careful timing and a few preventative measures will ensure a bountiful harvest. Our 214-day growing season gives you ample opportunity to enjoy multiple plantings of this fast-growing crop.

Starting mustard greens indoors isn't essential in our Mid-Atlantic climate, but it can give you a head start, especially for an early spring harvest. Start seeds indoors from mid February through mid March, about three weeks before you plan to transplant them outside.

Use seed trays or small pots filled with a good seed-starting mix. Provide warmth and plenty of light – a sunny windowsill or grow lights work well. Bottom watering helps prevent damping-off, which can be an issue in our sometimes-damp spring weather.

Transplant your mustard green seedlings outdoors from mid March through late April, after hardening them off for about a week. This gradual exposure to outdoor conditions helps them adjust to the sun and wind.

Space the plants 6-12 inches apart to allow for good air circulation, which is important given our humid springs. Keep an eye out for late frost warnings, which can still occur during this period; be prepared to cover your young plants if necessary.

Direct sowing mustard greens is a great option for our Mid-Atlantic gardens, offering a continuous harvest throughout the growing season. Sow seeds directly into the garden from early March through early September.

Prepare the soil by loosening it and adding compost. Ensure the soil temperature is at least 45°F for good germination. Sow seeds about ½ inch deep, spacing them 6-12 inches apart. Thin seedlings as needed to ensure proper spacing.

Consistent watering is key to growing healthy mustard greens in the Mid-Atlantic. While we generally have reliable rainfall, our humid summers can also bring periods of drought, so it’s important to monitor your plants. Mustard greens need moderate moisture.

Check the soil moisture regularly by using the "finger test" – stick your finger about two inches deep into the soil. If it feels dry, it's time to water. Aim for about 1 inch of water per week, either through rainfall or irrigation. During hotter periods, you may need to water more frequently.

Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our humid climate. Overwatering can lead to root rot, while underwatering can stress the plants, making the leaves spicier and triggering bolting. Mulching around your plants helps retain moisture and keeps the soil cool.

You can expect your first harvest of mustard greens from mid April through early November, about 45 days after planting. The best time to harvest is when the leaves are young and tender for a milder flavor.

You can harvest individual leaves as needed, starting with the outer ones, or cut the entire plant about an inch above the soil. This allows the plant to regrow for a second harvest. Regularly harvesting encourages continued production.

As the first frost approaches in early November, harvest any remaining mature leaves to enjoy before the cold weather sets in. You might even get a few more weeks of growth under a cold frame or row cover.

Mustard greens, like any crop, can face challenges in the Mid-Atlantic. Here are some common problems and how to deal with them:

Flea Beetles

• What it looks like: Tiny round holes (shot-hole pattern) in leaves. You'll see small, dark beetles that jump when disturbed. They cause the worst damage to young seedlings.
• What causes it: These small jumping beetles feed on the leaves of brassicas. They are most damaging to small, young plants and thrive in drier conditions.
• How to fix/prevent it: Use row covers to protect seedlings during their vulnerable stage. Delay planting until plants are larger. You can also use a kaolin clay coating or neem oil spray. Interplant with basil or catnip. Healthy, vigorous plants usually outgrow the damage.

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. You'll also see sticky honeydew residue and curled or distorted new growth.
• What causes it: These rapid-reproducing sap-sucking insects thrive in warm weather. Ant colonies may farm them for honeydew.
• How to fix/prevent it: A strong water spray can knock them off. Encourage ladybugs and lacewings, which are natural predators. Use insecticidal soap for heavy infestations. Neem oil also works well. Avoid excess nitrogen fertilizer, as it attracts them.

Cabbage Worms

• What it looks like: Smooth green caterpillars on brassica leaves. You'll see irregular holes chewed in leaves and dark green droppings. White butterflies will be hovering around your plants.
• What causes it: These are the larvae of white cabbage butterflies. There are multiple generations per season in our warm climate.
• How to fix/prevent it: Bt spray is very effective. Floating row covers can prevent egg laying. You can also handpick the caterpillars. Interplant with aromatic herbs like thyme and sage, and encourage parasitic wasps.

Bolting in Heat

• What it looks like: The cool-season crop sends up a flower stalk when temperatures rise. The leaves become tough and bitter, and harvest quality declines.
• What causes it: Extended warm temperatures above the crop's comfort zone cause this. Brassicas bolt when days consistently exceed 80°F.
• How to fix/prevent it: Time your plantings for cool weather in spring and fall. Choose bolt-resistant varieties. Provide shade during warm spells with shade cloth. Mulch to keep the soil cool, and harvest before bolting progresses.

Mid-Atlantic Specific Challenges: Our moderate-to-hot summers and humid climate can exacerbate problems with bolting and fungal diseases. Even rainfall helps, but monitoring moisture levels is still crucial. Deer pressure can also be significant, so fencing or repellents may be necessary.

Companion planting can be a great way to improve the health and yield of your mustard greens. Onions and garlic are good companions because their strong scent deters pests. Beets also make good neighbors, as they don't compete for the same nutrients. Dill attracts beneficial insects that prey on aphids and other pests. Lettuce provides 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, and tomatoes can stunt the growth of mustard greens.