Green Onions in Zone 8B — Gulf Coast

Green onions are a Gulf Coast garden staple. Their mild, fresh flavor is perfect in everything from gumbo to summer salads. Plus, they're incredibly easy to grow, providing a steady supply of flavorful greens throughout our long growing season.

While our high humidity can bring disease pressure, the extended warm weather gives you a huge head start. With a little attention to watering and airflow, you can enjoy green onions from late spring well into early winter, thanks to our 284-day growing season.

You can transplant green onion seedlings outdoors from late January through mid-February. This gives them a head start before the summer heat kicks in. Before planting, be sure to harden off your seedlings by gradually exposing them to the outdoors for about a week.

Space the seedlings about 2-3 inches apart in rows. At this time of year, keep an eye on the weather forecast for any late cold snaps. Cover your transplants with a frost blanket if temperatures are predicted to dip near freezing.

Direct sowing is the easiest way to grow green onions here in the Gulf Coast. You can sow seeds directly into the garden from late January through mid-September. This gives you multiple planting windows 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 about ¼ inch deep, spacing them 2-3 inches apart. Keep the soil consistently moist until they germinate. For a super easy start, you can also plant the root ends of store-bought green onions—just stick them in the soil, and they'll regrow.

Consistent moisture is key to growing tender, flavorful green onions in our climate. The high humidity can trick you, but green onions have shallow roots that dry out quickly, especially in the summer heat.

During the hotter months (June-August), you'll likely need to water every other day, providing about 1 inch of water per week. Use the finger test: 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 and increasing disease pressure in our humid environment. In the cooler months, you can reduce watering to once or twice a week, depending on rainfall.

Signs of underwatering include yellowing leaves and stunted growth. Overwatering can lead to bulb rot, so make sure your soil drains well. A layer of pine straw mulch can help retain moisture and suppress weeds, but avoid piling it directly against the stems to prevent rot.

You can expect your first harvest of green onions from late March through early December, about 60 days after planting. They're ready to harvest when the stalks are about pencil-thick.

You can either pull up the entire plant or cut the green onions off about an inch above the soil line. If you cut them, they'll usually regrow, giving you multiple harvests. As the first frost approaches in early December, harvest any remaining green onions to use or freeze, or cover them with a thick layer of mulch to try and extend the harvest a bit longer.

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

Onion Maggots

• What it looks like: Yellowing and wilting plants, often with maggots visible near the base of the bulb.
• What causes it: These pests thrive in moist soil.
• How to fix/prevent it: Rotate crops, use row covers, and apply beneficial nematodes to the soil.

Thrips

• What it looks like: Silvery streaks or white patches on the leaves, distorted growth.
• What causes it: These tiny insects suck plant juices, thriving in hot, dry conditions.
• How to fix/prevent it: Encourage beneficial insects like ladybugs, use insecticidal soap, and ensure adequate watering.

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 may wilt.
• What causes it: A soilborne fungus that favors warm, moist conditions.
• How to fix/prevent it: Improve soil drainage, rotate crops, and solarize the soil during the hottest part of the summer.

Gulf Coast Specific Challenges: The hot heat, very-high humidity, and wet-year-round rainfall of the Gulf Coast create ideal conditions for fungal diseases like downy mildew and root rot. Good air circulation, proper watering techniques, and disease-resistant varieties are essential for success.

Green onions are great companions for many plants in your Gulf Coast garden. Plant them near carrots, as they deter carrot root flies. They also benefit lettuce by repelling aphids. Tomatoes and peppers thrive alongside green onions, as the onions help deter pests like spider mites. Beets also enjoy the company of green onions.

Avoid planting green onions near beans and peas, as they can inhibit each other's growth.