Green Onions in Zone 6B — Northeast

Green onions are a must-grow in any Northeast garden. Their fresh, mild flavor elevates everything from summer salads to grilled dishes, and nothing beats the convenience of snipping a few from your garden right when you need them. Plus, the cool nights we often get here in the Northeast seem to make them even sweeter.

Our short growing season and occasional late frosts can be a challenge, but with a little planning, you can enjoy a steady supply of green onions from mid-May all the way through late October. With our 183-day growing season, you'll be harvesting these tasty treats in no time.

You can transplant green onion seedlings outdoors starting in mid-March through mid-April. Just be sure to harden them off first by gradually exposing them to outdoor conditions for about a week. This will help them adjust to the cooler temperatures and stronger sunlight.

Space your transplants about 2-3 inches apart in rows. Keep an eye on the weather forecast, as late frosts are always a possibility here in the Northeast. If a frost threatens, cover your seedlings with frost blankets or cloches to protect them.

Direct sowing is the easiest way to grow green onions in our region. You can start sowing seeds as early as mid-March and continue through early August for a continuous harvest. Green onions are very easy to direct sow.

Prepare your soil by loosening it and removing any rocks or debris. Green onions aren't too picky, but they'll appreciate a little compost mixed in. Sow seeds about ½ inch deep and 2-3 inches apart. Keep the soil consistently moist until the seedlings emerge. You can even plant the root ends of store-bought green onions for a quick start!

Green onions need consistent moisture to thrive, especially here in the Northeast where our summers can be moderately humid. Aim to keep the soil evenly moist, but not soggy. Remember, their shallow roots dry out quickly.

During the spring and fall, when temperatures are cooler and rainfall is more frequent, you may only need to water once or twice a week. In the heat of summer, especially during dry spells, you might need to water every other day. Stick your finger about two inches deep into the soil – if it feels dry, it's time to water. Aim for about an inch of water per week, either from rainfall or irrigation. It's best to water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our humid climate.

If the leaves start to yellow or wilt, it's a sign that the plants are either underwatered or overwatered. Check the soil moisture to determine the cause. A light layer of mulch, like straw or shredded leaves, can help retain moisture and suppress weeds, which is especially helpful in our variable Northeast climate.

You can expect your first harvest of green onions starting in mid-May, about 60 days after sowing. You can continue harvesting all the way through late October. The stalks should be about pencil-thick.

You can either pull up the entire plant or cut the green tops off about an inch above the soil line. If you cut them, they'll usually regrow for another harvest or two. As the first frost approaches in mid- October, harvest any remaining green onions or cover them with a thick layer of mulch for a slightly extended harvest.

Here are some common problems you might encounter growing green onions in the Northeast:

• 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. The larvae then burrow into the roots.
• How to fix/prevent it: Use row covers to prevent the adult flies from laying eggs. Rotate your crops each year. Introduce beneficial nematodes to the soil.
• Thrips
• What it looks like: Tiny, slender insects on the leaves, causing silvery streaks and distorted growth.
• What causes it: Thrips thrive in warm, dry conditions, but can still be a problem in our Northeast summers.
• 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 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 your crops each year. Plant resistant varieties if available.

Northeast Specific Challenges: Our moderate summer heat, moderate-to-humid humidity, and even rainfall can create favorable conditions for downy mildew and pink root. Be sure to provide good air circulation and avoid overhead watering. The rocky New England soil can also make it difficult for the roots to penetrate, so be sure to amend your soil with plenty of compost.

Companion planting can really boost your green onion crop here in the Northeast. Carrots are great companions because they deter onion flies, while the onions deter carrot root flies. Lettuce benefits from the pest-repelling properties of green onions.

Tomatoes and peppers also do well near green onions, as the onions can help repel aphids and other pests. Beets are another good choice, as they don't compete for the same nutrients. Avoid planting green onions near beans or peas, as they can inhibit each other's growth.