Green Onions in Zone 7A — Southeast

Green onions are a must-grow for any Southeast garden. Their mild, fresh flavor is fantastic in everything from summer salads to grilled meats. And with our long growing season, you can have a steady supply from spring well into fall.

Our hot and humid summers here can be a challenge, but green onions are surprisingly resilient if you time things right. With a 225-day growing season, you'll have plenty of opportunities to get multiple harvests.

You can transplant green onion seedlings outdoors from late February through late March. Before you put them in the ground, be sure to harden them off. Give them about a week of gradually increasing outdoor exposure.

Space the transplants about 2-3 inches apart in well-drained soil. Keep an eye out for late frosts, which can happen even in the Southeast. Be ready to cover them if a cold snap is predicted.

Direct sowing is the easiest way to grow green onions, and it works great in our Southeast climate. You can sow seeds directly into the garden from late February through late August. This gives you a long window for succession planting and a continuous harvest.

Choose a spot with full sun to partial shade and prepare the soil by loosening it and adding compost. Green onions aren't too picky, but they do appreciate well-drained soil. Sow seeds about ¼ inch deep and 2-3 inches apart. Keep the soil consistently moist until they germinate. You can also plant the root ends of store-bought green onions; just stick them in the ground and keep them watered!

Green onions need consistent moisture to thrive, but they don't like to sit in soggy soil. During our typically wet summers, you might not need to water as much, but during drier spells, they'll definitely need a boost. Aim to keep the soil consistently moist, especially when they're actively growing.

Stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Generally, they need about 1 inch of water per week, whether from rain or irrigation. It's usually best to water at the base of the plants to avoid getting the foliage wet, which can encourage fungal diseases in our humid climate.

If the leaves start to turn yellow or droop, it could be a sign of overwatering. If the tips of the leaves turn brown and crispy, they're likely underwatered. A layer of mulch around the base of the plants can help retain moisture and keep the soil cooler during our long, hot summer.

You can expect your first harvest of green onions starting in late April and continuing through mid-November. They're usually ready to harvest about 60 days after planting, or when the stalks are about pencil-thick. Don't worry about them getting too big; smaller is better for flavor.

You can either pull up the entire plant or cut the green onion off about an inch above the soil line. If you cut them, they'll usually regrow, giving you multiple harvests from the same plant. As our first frost approaches around early November, 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 Southeast:

Onion Maggots

• What it looks like: Wilting or yellowing leaves, stunted growth, and small white maggots feeding on the roots and bulb.
• What causes it: These pests are attracted to the smell of onions and lay their eggs near the base of the plants.
• How to fix/prevent it: Use row covers to prevent the adult flies from laying eggs. You can also apply beneficial nematodes to the soil to control the larvae.

Thrips

• What it looks like: Silver streaks or white blotches on the leaves, distorted growth, and tiny, slender insects visible on the plants.
• What causes it: These small pests suck the sap from the leaves, causing damage. They thrive in hot, dry conditions.
• How to fix/prevent it: Encourage beneficial insects like ladybugs and lacewings. You can also spray the 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.
• 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 infects the roots, preventing them from absorbing water and nutrients.
• How to fix/prevent it: Improve soil drainage and avoid overwatering. Rotate crops and 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. Be sure to provide good air circulation, water at the base of the plants, and consider using preventative fungicides if necessary. Also, keep an eye out for pests like onion maggots and thrips, which can be more prevalent during certain times of the year.

Good companions for green onions include carrots, lettuce, tomatoes, peppers, and beets. Carrots help deter onion flies, while onions deter carrot flies. Lettuce provides ground cover and helps retain moisture. Tomatoes and peppers benefit from the onion's pest-repelling properties. Beets loosen the soil, making it easier for green onions to grow.

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