Green Onions in Zone 7A — Midwest

Green onions are a must-grow in any Midwest garden. Their fresh, mild flavor elevates everything from grilled summer salads to cozy fall soups. Plus, they're incredibly easy to grow, offering a quick and satisfying harvest in our fertile soil.

Midwest weather can be unpredictable, with late frosts in spring and summer heat spells. But green onions are surprisingly resilient, and with a 193-day growing season, you'll have plenty of opportunities to get them in the ground and enjoy a bountiful harvest.

You can transplant green onion seedlings outdoors in the Midwest from mid-March through early April. 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 outdoor conditions for about a week.

Space the seedlings 2-3 inches apart in well-drained soil. Keep an eye on the weather forecast; we sometimes get a late frost here in the Midwest, so be ready to cover your transplants if needed.

Direct sowing is the recommended method for growing green onions here in the Midwest. You can sow seeds from mid-March through early August, giving you multiple chances for a continuous harvest. Green onions are super easy to direct sow. You can also plant the root ends of store-bought green onions.

Prepare your soil by loosening it and removing any rocks or debris. Sow seeds about ½ inch deep and 2-3 inches apart. Keep the soil consistently moist until the seedlings emerge. Soil temperature should be at least 50°F for best germination.

Green onions need consistent moisture to thrive, especially with our moderate-to-hot summers and moderate-to-humid conditions. They aren't very drought-tolerant, so don't let them dry out. The key is consistent watering.

During the spring and fall, when temperatures are milder, water deeply about once a week, providing around 1 inch of water. In the heat of summer, you may need to water every other day, especially if we're experiencing a dry spell. 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 rather than overhead to minimize the risk of fungal diseases, which can be a problem with our moderate-to-humid summers. Yellowing leaves can indicate overwatering, while drooping leaves suggest underwatering. Mulching around your green onions with straw or shredded leaves will help retain moisture and suppress weeds.

You can expect your first harvest of green onions in the Midwest from mid-May through late October. Green onions are usually ready to harvest about 60 days after planting, when the stalks are about pencil-thick. Don't worry about being exact; harvest them at whatever size you prefer.

To harvest, you can either pull up the entire plant or cut the stalks about an inch above the base. If you cut them, they will often regrow, giving you multiple harvests from the same plant. As our first frost approaches in mid- October, harvest any remaining green onions to use fresh or preserve for later.

Green onions are generally easy to grow, but here are some common problems you might encounter in the Midwest:

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: Onion maggots are the larvae of a fly that lays its eggs near onion plants. They thrive in moist soil, which we often have in the Midwest, especially during our wet springs.
• How to fix/prevent it: Use row covers to prevent the flies from laying eggs. Remove and destroy any infested plants. Consider using beneficial nematodes to control the maggots in the soil.

Thrips

• What it looks like: Silvery or white streaks on the leaves, distorted growth, and tiny, slender insects on the plant.
• What causes it: Thrips are tiny insects that suck the sap from plants. They are more prevalent during hot, dry weather, but can still be a problem during our summer heat spells.
• How to fix/prevent it: Encourage beneficial insects like ladybugs and lacewings. Use insecticidal soap or neem oil to control severe infestations.

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. It's more common during our wet springs or periods of high humidity in the summer.
• How to fix/prevent it: Remove affected leaves immediately. Improve air circulation. Water at the base, never overhead. Copper-based fungicides for prevention. Plant resistant varieties where available.

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. It's more common in warm, wet soils, which can be an issue in the Midwest.
• How to fix/prevent it: Improve soil drainage. Rotate crops to avoid planting onions in the same location year after year. Solarize the soil to kill the fungus.

Midwest Specific Challenges: The moderate-to-hot heat and moderate-to-humid humidity of our Midwest summers can create favorable conditions for both pests and diseases in green onions. Good air circulation and proper watering techniques are key to preventing problems.

Companion planting can really give your green onions a boost here in the Midwest.

Good companions for green onions include:

• Carrots: They deter onion flies.
• Lettuce: It provides ground cover, keeping the soil cool and moist.
• Tomatoes and Peppers: Green onions can repel some pests that bother these crops.
• Beets: Improve soil health and nutrient uptake.

Avoid planting green onions near:

• Beans and Peas: They can inhibit each other's growth.