How to Grow Scallions

How to Grow Scallions
Green onions will develop a small bulb. For tender tops, harvest before the bulb gets much larger than these. Photo: starfish75 / staockexchange (http://www.freeimages.com/photo/520787)

Overview and Description

Although we use the terms scallions, green onions and spring onions interchangeably to mean any onion harvested before the bulb forms, I have heard them categorized as:

  • Green Onions - regular onions harvested before they form a bulb
  • Spring Onions - regular onions harvested when the bulb is smaller than a quarter
  • Scallions - varieties that never form a bulb

It's a fine point and an unscientific one.

There is a specific allium species, Allium fistulosum, that is a clump forming perennial that never grows into a bulb. These generally have the best flavor, but growing them as perennials can require a bit more care. I personally grow the perennial varieties, but use them as annuals. Scallions grow so fast, I simply succession plant.

Actually, you can re-root scallions from the grocery store. You may even have luck regrowing the ones you've used for cooking, if you leave a couple of inches of stem attached to the roots. You don't even have to plant them in the garden. Scallions will happily grow in a glass of water. When something is this ridiculously easy to grow, you might as well take every opportunity.

  • Leaves: Scallions have hollow, blade-like leaves that fold around each other at the base of the plant.
  • Flowers: The flowers grow on individual stems and start off covered in a papery sheath. The growing flower head will eventually split the sheath open. The round flower heads are globes of individual flowers.

    Latin Name

    Allium fistulosum or immature Allium cepa

    Common Names

    scallions, green onions, spring onions, bunching onions

    Hardiness Zones

    Perennial scallions are listed as hardy in USDA Zones 3 - 9. Other types are biennial, although a cold spell can make them think they have gone through winter, forcing them to go to seed their first year.

    Exposure

    These are leafy vegetables that can handle some partial shade, but they will do best and remain healthiest in full sun. Just keep in mind that they like regular water, so don't plant them in hot, dry soil.

    You can start seed indoors about 5 -6 weeks before your last frost date or wait a couple of weeks and direct sow in the garden. Either way, sow the seed about 12 in. deep and somewhat thickly (4 - 8 seeds per cell). Germination can be slow and poor. The most important thing scallion seed needs is constant moisture, which makes starting the seeds indoors, where you can keep an eye on the, a good choice.

    If you start them indoors, you can begin to harden them off as soon as the roots fill out the cell pack enough so that when you gently tug on them, they don't budge.

    In USDA Hardiness Zones 7 and above, you can begin direct sowing in September, for winter and spring harvesting.

    Planting Out: Plant your seedlings in a sunny spot. As with onions, scallions have a very shallow root system, so you may need to water them all season. However don't let them sit in wet soil. It should be moist, but well-draining.

    Thin seedlings to about 1 ft. apart. You can eat any plants you thin. To have a continual harvest, succession plant every 3 - 4 weeks.

    Along with keeping the plants watered, give them some supplemental fertilizer monthly. Something high in nitrogen, like fish emulsion, would keep them green and growing. The only other maintenance would be keeping the area weed free.

    If you are growing perennial scallions, apply a thick layer of mulch in late fall and remove it in spring, when the soil has warmed. You will get an earlier crop that way.

    Pest and Problems

    Most scallions are virtually problem free. If you do start noticing problems, rotating the next crop to a different area of the garden should help.

    Harvesting

    Scallions are tender and mild when they are young. You can start harvesting as soon as the plants reach about 5 - 6 in. tall and as wide as a pencil. Harvest the whole plant by pulling it out.

    If you planted perennial varieties, it is recommend you not harvest at all the first year, except for the thinnings.

    After that, you can lift the clump, divide the roots (you may need to use a knife) and re-pant 1 or more of the divisions. I have not had the patience to do this, so I can't speak from experience. It seems easier to me to just seed more.

    Suggested Varieties

    Honestly, I haven't had a bad variety. If you harvest often, they are always crunchy-tender and flavorful.

    • 'Evergreen White Bunching' - A perennial variety that is nice for a winter crop in a cold frame. (60 days)
    • 'Guardsman' - falls somewhere between a scallion and a spring onion. (50 days)
    • 'Nabechan' - a Japanese variety prized for its flavor (60 days)
    • 'Red Beard' - quick and easy to grow. Purple-red stalks. (50 days)
    • 'Tokyo Long White' - another flavorful perennial variety. (75 - 90 days)