Green Onions in Zone 6A — Midwest

Green onions are a must-grow for any Midwest gardener. Their mild, fresh flavor is perfect in everything from summer salads to grilled dishes. Plus, they're incredibly easy and rewarding to grow in our fertile soil and with our reliable summer heat.

We all know Midwest weather can be a bit unpredictable, especially in spring with temperature swings, but green onions are pretty forgiving. With a long 178-day growing season, you'll have plenty of opportunities to get them in the ground and enjoy a continuous harvest.

If you're starting green onions indoors, you can transplant them outdoors from late March through mid April. Before planting, be sure to harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This prevents shock.

Space your transplants 2-3 inches apart in rows. Keep an eye on the Midwest weather forecast for any late frosts; cover your seedlings if necessary to protect them.

Direct sowing is the easiest way to grow green onions in the Midwest. You can sow seeds directly into your garden from late March through early August, giving you multiple chances for a continuous harvest.

Prepare your soil by loosening it and adding compost. Green onions aren't too picky, but they prefer well-draining soil. Sow seeds about ½ inch deep and 2-3 inches apart. Keep the soil consistently moist until the seedlings emerge. You can also plant the root ends of store-bought green onions – just stick them in the ground and watch them grow!

Green onions need consistent moisture to thrive, especially in our Midwest summers. While we often get good rainfall, those summer heat spells can dry things out quickly. Aim to keep the soil evenly moist, but not waterlogged.

A good rule of thumb is to water deeply about once a week, providing about 1 inch of water. Use the finger test: stick your finger about 2 inches into the soil. If it feels dry, it's time to water. During hotter periods, you might need to water more frequently. Water at the base of the plants rather than overhead to prevent fungal diseases, as our humidity can be a factor.

Signs of underwatering include yellowing leaves and stunted growth. Overwatering can lead to root rot, so watch for wilting or mushy stalks. A light layer of mulch, like straw or shredded leaves, can help retain moisture and regulate soil temperature.

You can expect your first harvest of green onions starting in late May and continuing through late October in the Midwest. They're typically ready to harvest about 60 days after planting, when the stalks are pencil-thick.

You can either pull up the entire plant or cut the green onion about an inch above the soil line. If you cut them, they'll often regrow for a second harvest. To encourage continued production, harvest regularly.

As the first frost approaches in mid- October, harvest any remaining green onions. You can chop and freeze them for later use, or even try overwintering some in a protected area with heavy mulch for an early spring harvest next year.

Here are some common problems Midwest gardeners face with green onions:

• 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 are attracted to the smell of onions and lay their eggs near the base of the plants. Our variable spring weather can sometimes lead to early infestations.
• How to fix/prevent it: Use row covers to prevent the adult flies from laying eggs. Apply beneficial nematodes to the soil. Remove and destroy any infested plants.
• Thrips
• What it looks like: Silvery or white streaks on the leaves, distorted growth, and tiny, slender insects visible on the plant.
• What causes it: Thrips thrive in hot, dry conditions and suck the sap from the leaves. Summer heat spells can exacerbate thrip problems.
• How to fix/prevent it: Spray plants with a strong stream of water to dislodge the thrips. Use insecticidal soap or neem oil. Encourage beneficial insects like ladybugs and lacewings.
• 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 red, and the plant's growth is stunted.
• What causes it: A soilborne fungus that thrives in warm, wet conditions. Our wet summers can increase the risk of pink root.
• How to fix/prevent it: Improve soil drainage by adding compost. Rotate crops to avoid planting onions in the same spot year after year. Solarize the soil in the summer to kill the fungus.

Midwest Specific Challenges: The moderate-to-hot summers and moderate-to-humid humidity, combined with periods of heavy rainfall, create conditions that can favor both pests and diseases in green onions. Be vigilant about monitoring your plants and taking preventative measures to keep them healthy.

Green onions play well with many other garden veggies. Carrots benefit from green onions because the onion's scent deters carrot root flies. Lettuce thrives near green onions because they help repel aphids. Tomatoes and peppers also appreciate the pest-repelling properties of green onions. Beets are also good companions, as green onions can help deter leaf miners.

Avoid planting green onions near beans or peas, as they can inhibit each other's growth. The alliums in green onions can stunt the growth of legumes.