Green Onions in Zone 8B — Southeast

Green onions are a must-have in any Southeastern garden. Their mild, fresh flavor elevates everything from grilled fish to summer salads, and they're incredibly versatile in the kitchen. Plus, there's real satisfaction in snipping a few from your garden right when you need them.

Our hot and humid summers can bring challenges like fungal diseases and pests, but with a little planning, you can enjoy a continuous harvest of green onions. With our long 255-day growing season, there's plenty of time to get them established and producing.

You can transplant green onion seedlings outdoors in early February through early March. Start your seeds indoors a few weeks beforehand if you want a head start.

Before planting, be sure to harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This prevents transplant shock. Space your green onions about 2-3 inches apart in well-draining soil.

Keep an eye on the weather forecast here in the Southeast. A late cold snap isn't uncommon, so be prepared to cover your seedlings if temperatures dip near freezing.

Direct sowing is the easiest way to grow green onions here in the Southeast. You can sow seeds directly into your garden beds from early February through early September, giving you a continuous supply. Soil temperatures should be at least 50°F for good germination.

Prepare your soil by loosening it and amending with compost to improve drainage, as our clay soil can be challenging. Sow seeds about ¼ inch deep and 2-3 inches apart. Keep the soil consistently moist until germination, which usually takes about a week.

Here's a little trick: you can also plant the root ends of store-bought green onions! Just stick them in the ground, and they'll regrow.

Green onions need consistent moisture to thrive, especially during our hot summers. They aren’t drought-tolerant, and their shallow roots can dry out quickly. The key is to find the right balance, especially with our humid climate and frequent afternoon thunderstorms.

During the spring and fall, when temperatures are milder, water deeply about once a week, providing roughly 1 inch of water. In the heat of summer, you might need to water every other day, especially if you haven't had recent rainfall. Stick your finger about 2 inches into the soil – if it feels dry, it's time to water.

Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our humid climate. Overwatering can lead to rot, so make sure the soil is well-draining. Yellowing leaves can indicate overwatering, while drooping or wilting leaves signal underwatering. Applying a layer of mulch, like pine straw or shredded leaves, helps retain moisture and suppress weeds.

You can expect your first harvest of green onions starting in mid-April and continuing through late November in our Zone 8B climate. Green onions are typically ready to harvest about 60-70 days after planting.

Look for stalks that are at least pencil-thick. You can either pull the entire plant or cut the stalks about an inch above the soil line. If you cut them, they'll often regrow, giving you multiple harvests.

To encourage continuous production, harvest regularly. As our first frost approaches in mid- November, harvest any remaining green onions to use fresh or preserve. You can also pot up a few plants and bring them indoors to extend your harvest through the winter.

Here are some common problems you might encounter with green onions in the Southeast:

Onion Maggots

• What it looks like: Wilting or yellowing plants, stunted growth, and small white maggots feeding on the roots and bulb.
• What causes it: These pests thrive in moist soil and are attracted to the smell of onions.
• How to fix/prevent it: Use row covers to prevent adult flies from laying eggs. Remove and destroy infested plants. Introduce beneficial nematodes to the soil.

Thrips

• What it looks like: Silvery streaks or spots on the leaves, distorted growth, and tiny, slender insects.
• What causes it: Thrips are more prevalent during hot, dry periods.
• How to fix/prevent it: Encourage beneficial insects like ladybugs and lacewings. Spray plants with insecticidal soap or neem oil.

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. Different species affect different plants.
• 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: Pink or reddish roots, stunted growth, and yellowing leaves.
• What causes it: A soilborne fungus that is more common in warm, wet conditions.
• How to fix/prevent it: Improve soil drainage. Rotate crops to avoid planting onions in the same spot year after year. Plant resistant varieties if available.

Southeast Specific Challenges Our hot, humid summers and wet-summer rainfall create ideal conditions for fungal diseases like downy mildew and pests. Monitor your plants regularly, provide good air circulation, and water at the base to minimize these problems. Our clay soil needs amending with organic matter to improve drainage and prevent root rot.

Companion planting can really benefit your green onions here in the Southeast. Carrots are great companions because their scent repels onion flies, and green onions deter carrot root flies. Lettuce benefits from the shade provided by green onions, especially during our long summer.

Tomatoes and peppers also make good companions, as green onions can help repel certain pests that attack these crops. Beets help to loosen the soil around green onions, improving drainage, which is especially helpful with our clay soil.

Avoid planting green onions near beans or peas. They can inhibit the growth of these legumes, reducing your overall harvest.