Green Onions in Zone 9A — Gulf Coast

Green onions are a must-grow for us Gulf Coast gardeners. Their mild, fresh flavor brightens up everything from gumbo to summer salads, and they're so easy to snip right when you need them. Plus, there’s nothing quite like the satisfaction of pulling up a bunch of homegrown green onions, especially when the humidity is so high you feel like you’ve earned it!

We definitely have our share of challenges here with the heat and humidity, but don't let that scare you off. Our long growing season, around 303 days, means you can plant green onions multiple times a year. With a little planning, you can have fresh green onions almost year-round.

If you're starting green onions from transplants, aim to get them in the ground from mid-January through early February. This gives them a good head start before the real heat kicks in. Before planting, harden them off by gradually exposing them to the outdoors for about a week.

Space the transplants about 2-3 inches apart. Keep an eye on the weather during this time; we can still get some unexpected cold snaps. If a freeze is predicted, cover your seedlings to protect them.

Direct sowing is the easiest way to grow green onions here. You can sow seeds from mid-January through late September. Pick a spot that gets full sun to partial shade. Green onions aren't too picky, but they do best in well-drained soil. Loosen the soil and mix in some compost before planting.

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 the white ends, root-side down, into the soil. They'll sprout new green shoots in no time!

Watering is key to growing great green onions, especially with our Gulf Coast climate. They need consistent moisture to stay tender and mild. Those shallow roots can dry out fast, particularly during our hot, humid summers.

During the hotter months, you'll likely need to water every other day, or even daily if we're in a dry spell. In the cooler months, you can usually get away with watering every few days. Stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Aim for about 1 inch of water per week, either from rain or irrigation. It's best to water at the base of the plants to avoid getting the leaves wet, which can encourage fungal diseases in our high humidity.

If the leaves start to yellow or droop, you might be overwatering. If they look wilted and dry, you're likely underwatering. Adding a layer of mulch, like pine straw, can help retain moisture and keep the soil cool.

You can expect your first harvest of green onions around mid-March through mid-December, about 60 days after planting. Look for stalks that are at least 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 from the same plant.

To encourage continued production, make sure to keep the plants watered and fertilized. As we approach the first frost in early December, harvest any remaining green onions. They can tolerate a light frost, but a hard freeze will damage them.

Green onions, like any crop, can have their share of problems here on the Gulf Coast. Here are a few to watch out for:

• Onion Maggots
• What it looks like: Wilting or yellowing plants, especially young seedlings. If you dig up the plant, you'll find small, white maggots feeding on the roots and bulb.
• What causes it: These pests thrive in moist soil.
• How to fix/prevent it: Use row covers to prevent the adult flies from laying eggs near your 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 (thrips) on the plants.
• What causes it: Thrips are attracted to hot, dry conditions, but they can still be a problem here.
• How to fix/prevent it: Encourage beneficial insects like ladybugs and lacewings. Spray plants with a strong stream of water or use insecticidal soap.
• 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: The roots turn pink or reddish, and the plants become stunted and weak.
• What causes it: A soilborne fungus that thrives 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.

Gulf Coast Specific Challenges: Our hot, humid climate and wet-year-round rainfall create the perfect environment for fungal diseases. Make sure to provide good air circulation, water at the base of the plants, and consider using preventative fungicides.

Companion planting can be a big help in the garden. Green onions have some great friends:

• Carrots: Green onions repel carrot root flies, while carrots repel onion flies. It's a win-win!
• Lettuce: Green onions help deter aphids and other pests that can bother lettuce.
• Tomatoes & Peppers: Green onions can help repel some pests that attack tomatoes and peppers.
• Beets: Green onions can help deter flea beetles that sometimes bother beets.

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