Green Onions in Zone 5B — Mid-Atlantic

Green onions are a must-have in any Mid-Atlantic garden. They're incredibly versatile in the kitchen, adding a mild onion flavor to everything from salads to stir-fries, plus they're easy to grow and harvest throughout our four seasons. There's nothing quite like snipping fresh green onions from your own garden for a summer barbecue.

Our region's humid summers and variable spring weather can present challenges, but with careful timing, you can enjoy a continuous harvest of green onions during our 178-day growing season.

You can transplant green onion seedlings outdoors in the Mid-Atlantic from late March through mid April. Before transplanting, be sure to harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This will help them adjust to the temperature swings we often see this time of year.

When transplanting, space the seedlings 2-3 inches apart in rows. Keep an eye on the weather forecast. We can still get a late frost in April, so be prepared to cover your transplants if necessary.

Direct sowing is the easiest way to grow green onions here. Sow seeds from late March through early August for a continuous supply. Choose a spot with full sun to partial shade and well-drained soil.

Before sowing, amend your soil with compost to improve drainage and fertility. Green onions prefer a soil temperature between 60-70°F for optimal germination. Sow seeds about ¼ inch deep and 2-3 inches apart. You can also plant the root ends of store-bought green onions directly into the soil, which is a quick and easy way to get started.

Green onions need consistent moisture to thrive, but avoid waterlogged soil. During our moderate-to-hot summers, you'll likely need to water more frequently than in the cooler spring and fall months. Aim to keep the soil consistently moist to the touch.

Check the soil moisture by sticking your finger about 2 inches deep. If it feels dry, it's time to water. Generally, green onions need about 1 inch of water per week, either from rainfall or irrigation. Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our humid climate.

Signs of underwatering include yellowing leaves and stunted growth. Overwatering, on the other hand, can lead to root rot. Add a layer of mulch around your green onions to help retain moisture and suppress weeds.

You can start harvesting green onions about 60 days after planting, typically from late May through late October in the Mid-Atlantic. Look for stalks that are at least pencil-thick. These are usually ready about 60-70 days after planting.

To harvest, you can either pull up the entire plant or cut the stalks about an inch above the soil line. If you cut them, they will often regrow for a second harvest. As our first frost approaches in mid- October, harvest any remaining green onions to use fresh or freeze for later.

Here are some common problems you might encounter with green onions in the Mid-Atlantic:

• Onion Maggots
• What it looks like: Yellowing or wilting foliage, stunted growth, and small white maggots feeding on the roots and bulb.
• What causes it: These pests thrive in moist soil conditions.
• How to fix/prevent it: Use row covers to prevent adult flies from laying eggs. Apply beneficial nematodes to the soil.
• Thrips
• What it looks like: Silvery streaks or white patches on the leaves, distorted growth, and tiny, slender insects on the plant.
• What causes it: Thrips are attracted to stressed plants.
• How to fix/prevent it: Spray plants with insecticidal soap or neem oil. Ensure plants are well-watered and fertilized.
• Downy Mildew
• What it looks like: Yellow patches on leaf tops with fuzzy gray-purple growth on undersides. Leaves brown and die from the bottom up.
• What causes it: Oomycete pathogen that spreads in cool, humid conditions via wind-carried spores.
• How to fix/prevent it: Remove affected leaves immediately. Improve air circulation. Water at the base, never overhead. Copper-based fungicides for prevention.
• Pink Root
• What it looks like: Roots turn pink or reddish, plants are stunted, and leaves may yellow and die.
• What causes it: A soilborne fungus that thrives in warm, wet conditions.
• How to fix/prevent it: Improve soil drainage. Rotate crops to avoid build-up of the fungus in the soil.

Mid-Atlantic Specific Challenges: Our moderate-to-hot, humid summers and even rainfall can create ideal conditions for fungal diseases like downy mildew. Good air circulation and proper watering techniques are essential for preventing these problems. Also, keep an eye out for deer pressure, which is common in many parts of the Mid-Atlantic.

Green onions are great companions for many plants in your Mid-Atlantic garden. Carrots benefit because the onion scent deters carrot root flies. Lettuce thrives when planted near green onions as they help repel aphids. Tomatoes and peppers also benefit from the pest-repelling properties of green onions. Beets are good companions because green onions can deter leaf miners.

Avoid planting green onions near beans and peas, as they can inhibit the growth of these legumes.