How to Grow Green Onions—Plus, Tips for Regrowing Them From Scraps

Green onions are great for topping salads, stir-fries, and other meals, and the best part is that you can easily grow these versatile vegetables in your home garden. Plant green onions in a container if you have a smaller space, or add them directly to your garden bed from seeds or seedlings. You can even regrow store-bought green onions on a sunny windowsill. To understand how to grow green onions, we spoke to expert gardeners who shared their tips for planting, harvesting, and more. 

When to Plant Green Onions

Green onions can be planted outdoors in mid-spring once the ground is workable and the threat of frost has passed, says Adam Weiss, gardener and founder of Pike Lane Gardens. You can also start green onions from seed indoors in early spring and transplant them outside eight to 10 weeks later. To determine the exact planting window for your area, you must know your USDA gardening zone, which tells you the last frost date in your region.

How and Where to Plant Green Onions

Before sowing your seeds, find an area in your garden with well-aerated, well-draining soil that receives at least eight hours of full sun. If starting seeds indoors, use seed starting mix and place the seeds by a sunny window or use grow lights. 

1. Sow seeds 1/4-inch to a 1/2-inch deep, spacing the rows 12 to 18 inches apart.
2. Cover the seeds lightly with soil. Water deeply.
3. Once the seedlings emerge, thin them out so there is one plant per inch.
   

How to Care for Green Onions 

Green onions are easy to care for. Just follow these simple tips for a thriving crop.

Sunlight

Green onions require at least eight hours of direct sunlight for maximum growth. They tolerate some shade but grow faster in an area with more sunlight. 

Soil

For the best results, plant green onions in soil with plenty of drainage. Opt for rich, sandy, loam soil with a slightly acidic to neutral pH level. Add organic matter, such as compost, to the soil to boost plant growth.

Water

Green onions need 1 inch of water per week to prevent the soil and roots from drying out. But be careful not to overwater green onions, as this may cause root rot. 

Temperature

Green onions grow well between 55 to 75 degrees Fahrenheit. Avoid growing green onions in extreme heat or cold, as both will kill your crop. 

Fertilizer

Work a balanced fertilizer, such as 10-10-10, into the soil before planting. Sidedress with additional fertilizer about four to five weeks after planting. 

Mulch

Make sure to mulch around the base of the seedlings. Weiss suggests adding 1/2 an inch of mulch around the plant for moisture retention, soil temperature control, and weed control.

How to Harvest and Store Green Onions

Harvest green onions once the stems are about 1/4 to 3/4 of an inch thick. Harvest the bulb by pulling it from the soil, washing it, and using as needed. Use a trowel to loosen the soil around the bulb if needed. Store the excess in the refrigerator to keep the green onions fresh for longer.

How to Regrow Green Onions From Scraps

To regrow or propagate green onions, slice off the end of the bulb, keeping the roots attached. Put the root end down in a small glass jar filled with water, leaving the top part of the onion above the waterline, says Sara Rubens, certified garden coach and founder of Seed to Sanctuary. “Then place it on a sunny windowsill, and the onion will continue to grow,” she says. Replace the water every few days to keep it fresh. Green shoots should grow from the top of the onion in a few days. 

Growing Green Onions in Containers 

Green onions grow well in containers. Plant them in 1-inch-deep (or deeper) pots filled with well-draining soil, says Rubens. Water the green onions frequently, as containers dry out quicker than in-ground beds.

There is typically no need to repot green onions. “Generally, green onions do not like to be repotted, as their roots will get disturbed,” Rubens says. Instead, choose a container on the larger side to avoid needing to relocate your green onion as it grows.

Common Problems

Green onions are susceptible to a few issues, regardless of how well you care for them. For instance, several common garden pests may invade your green onions, including aphids, thrips, cutworms, and leaf miners, says Weiss, “Heavy rain, poor soil, and improper spacing can increase the likelihood of pests,” he adds.

To prevent pests, you can use proactive best practices such as mulching and checking your plants regularly. “I never go more than two days without checking for pests so that I can proactively manage and treat any potential problems," Weiss says.