Green onions, aka scallions or bunching onions, make a great flavor addition and garnish for just about any dish, and once you start growing your own at home, you’ll wonder why you ever bought the little bunches from the grocery store! They’re easy to grow, and a great option for gardeners with any amount of space, from just a pot on a windowsill to a whole backyard full of garden beds. Here’s a guide to growing your own green onions at home.
How to Grow Green Onions
Green onions are a hardy, low-maintenance crop that mainly needs plenty of sun, and rich, well-draining soil. Make sure to amend your garden bed with an inch or two of compost before planting, or use a high-quality potting mix if you’re growing in a container.
When to Plant Green Onions
You can plant green onions indoors 8-10 weeks before your last frost to get a jump on the season, or direct-seed them outdoors throughout the summer and into early fall. They’ll do best in cool temperatures, but a little afternoon shade can help them take some summer heat. Most varieties are frost-tolerant, but none will tolerate long periods of below-freezing temperatures, so some type of season extension, such as row cover or a cold frame, is a must for most gardeners who want to harvest green onions into winter.
How to Plant Green Onions
Onions have tiny, threadlike, delicate sprouts that can be easily knocked over, so whether you’re starting them in trays indoors, or directly in the garden, a good trick is to plant them in small clumps rather than spread out in a row. That way, the seedlings support each other as they grow. To plant using this technique, make each planting hole about 1/4 inch deep, and drop about 6-8 seeds in. Space your clumps about 6 inches apart. If you’re starting your seeds indoors in a plug tray, plant several seeds per plug, and transplant the whole clump together once the seedlings have filled up the space. You can transplant green onions outside about 2-4 weeks before your last frost. If you’re direct-seeding, make sure temperatures are at least in the 50s F, to ensure good germination.
Maintaining Your Green Onion Crop
Overall, green onions are a low-maintenance crop! Some people like to hill up the soil around their scallions as they grow to get more white stem and less greens, but that’s just a matter of preference. Soil moisture is an important consideration though, since green onions have shallow root systems. Pay close attention and make sure to water as soon as the top half-inch or so of soil is dry. But, be careful not to leave the soil waterlogged for too long. It should be consistently moist, not soggy. Applying a liquid fertilizer like fish emulsion occasionally can give your green onions a boost. Green onions tend not to be bothered by too many pests, and a three-year crop rotation is good prevention for most of the diseases and insects that affect them. Snails and slugs can do a number on young plants however, so try to water in the morning and avoid leaving the soil surface wet overnight. Beer traps are a great non-toxic way to reduce slug and snail numbers if they are a problem in your garden.
When and How to Harvest Green Onions
Green onions can really be harvested at just about any stage (some people even grow them as microgreens!) Most gardeners begin harvesting their scallions when the stalks reach pencil thickness or more. If you’re growing your onions in clumps, pull up just one or two onions from each group at a time, to allow the others more space to grow. Many green onion varieties will get quite large if left in the ground long enough, up to 18 inches tall and a couple inches in diameter! If you only want the greens on the other hand, just clip them off about an inch or two above the soil line, and leave the roots in the ground. They’ll re-sprout more greens! If you see your plants putting up a central stalk with a bud on the end, that means they’re beginning to bolt (flower), and you should harvest them right away. (And eat the flower stalk, or “scape” too - they’re tasty, just like garlic scapes!) Green onions won’t taste very good after flowering, and will die soon after. Consistent watering and a little shade in the heat of summer will hold off bolting for as long as possible.
Tips for Growing Green Onions in a Container
Green onions are great for growing in a container, since their roots don’t grow very deep, and the plants can be harvested at any size. Make sure your pot or grow bag is at least six inches deep, and has good drainage. Choose a quality soil mix that is high in organic matter. And, if you’re container gardening indoors, make sure you either have a south-facing window with plenty of sunlight, or a good grow lamp.
How to Store Green Onions
One good way to store your green onions is upright in a glass of water in the fridge. They may even keep growing a tiny bit! Just cover the roots with water, don’t submerge them past the white stem part. Green onions also keep well chopped up and refrigerated in an airtight container. No matter how you choose to store them, the rule of thumb is to make sure leaves are not soggy from washing when they go in the fridge. Stored properly, green onions will last in the refrigerator for about a week.
The Best Green Onion Varieties to Grow
This popular scallion variety grows to 12-15” in height and is prized for its long tender white stems. A good all-purpose choice, as it can be grown in spring or fall or overwintered, and is great for cut-and-come-again production.
This Japanese green onion is particularly cold-hardy and great for overwintering.
Some bunching onions have beautiful red stems! Crimson Forest is a popular variety known for its vibrant color and mild flavor.
If you’re ready to try growing your own scallions at home, look for “Bunching Onion” seeds in our collection of onion varieties. Or, explore the different types of onions you can grow in your garden by reading up on perennial onions, and learning about short day versus long day bulbing onions on our blog!