Learn how to grow green onions and enjoy fresh onion flavor all year round. Green onions can be grown in two different ways, to help you have a continual harvest. Green onions can also be preserved, by freezing or dehydrating, if you have an abundance.
Onions are a staple in many foods, many cultures, and many areas of the world. Onions provide flavor in food, and have herbal qualities like being antimicrobial, and great for immune boosting. They’re a staple in Grandma’s chicken soup, with roast beef, as French onion soup, and even in salads.
What are green onions
Green onions are a member of the allium family of plants. This family includes chives, scallions, leeks, garlic, bulb onions, ramps, and even Egyptian walking onions. With many of our standard onions, like shallots, yellow onions, and walla walla onions, we use the bulb, or root portion. With green onions the most commonly used portion is the leaves, same as chives and Egyptian walking onions actually.
Green onions are largely a spring onion, and are harvested while the bulb is small. They are quicker to grow, outdoors, than typical bulb onions. They are also suitable for container growing, small spaces, and new gardeners.
Where to Plant:
If you’re growing green onions outdoors, you’ll want a nice spot of ground in full sun. Since you use the stalks of the onions, you can grow green onions in nitrogen rich ground, where you wouldn’t want to grow regular onions. Nitrogen promotes leaf and stalk growth, so it’ll help the green onions.
If you want to grow green onions indoors it’s a bit simpler. My favorite method involves a jar, and a sunny windowsill or grow light. That’s it!
When to plant:
Green onions are best planted in early spring, at the same time as your peas, lettuce, and radishes. This will depend on your last frost date, and your growing zone. Basically, as soon as the soil can be worked and is no longer frozen, get those seeds in the ground. You can also plant a second crop of green onions in the fall, usually around August, for a pre-winter harvest. Green onions take 50-60 days from germination to maturity.
Plant seeds in moist soil, scallion seeds or green onion seeds need a bit of light to germinate. So cover the seeds very lightly with dirt, or with a light layer of straw.
For indoor, jar, growing of green onions you can plant them at any time. I find the best time is usually right after I’ve bought a bunch, or a few bunches, of green onions from the supermarket. As long as the bunch has root ends, you can take the root end, with about 1/2 inch of space, and re-grow more green onion leaves from it.
How to plant green onions
For in-ground planting, the technique depends on your gardening technique. If you plant in rows, space rows one to two feet apart, and thinly seed them. If you use square foot gardening, plant seeds or seedlings about 2 inches apart in your squares.
You will want well drained soil, and if using a container, a well draining container. Too much soil moisture can contribute to root rot in the onions. Onions naturally have a shallow root system, so shallower containers can work better than deeper ones for onions.
For container gardening, use the square foot method for seeding or transplanting and plant the onions about 2 inches apart. Or thinly sprinkle the seeds over the surface of the container, and once germinated, thin the seedlings to two inches apart.
For the jar method, you will need a holder to hold the onion root bases in. A mesh basket works fine. Place 6 or so onion bases in the basket, and fill the jar with clean water.
How to grow green onions
Once you sow the onion seeds, germination will take 7-14 days. Onions have little need for fertilizer, but you can apply a balanced commercial one, or lightly top dress with composted manure or finished compost. Once the onions have germinated and been thinned, mulch the bed and the space between rows to preserve moisture. This also helps suppress weeds.
If working with a container, a layer of mulch can also help preserve moisture in the pot. I like placing containers so that they get full early morning, and late evening sun. But, don’t get the high afternoon sun, as it drys out containers very quickly.
With the jar method of growing, simply fill the jar with clean water. Change the water once every 3-5 days. When the onions have grown to a decent length, you can take scissors and give them a haircut. Then use the cut onions in your favorite green onion recipes.
When and how to harvest the crop
With outdoor onions, once they’ve been growing for about 60 days they can be harvested. Now, green onions in the garden, or in containers, will be harvested by pulling them up by the roots. Then, washing them, and trimming them before cool storage. Remember, green onions do not bulb up, and the stem will be about the same thickness as the root part.
With the jar method of how to grow green onions, once they reach six inches in height you can simply cut off the green part to harvest it. This way you can avoid grocery store onions in mid-winter, and one set of onion root bases can be trimmed or harvested 4-5 times before the growth slows down.The jar method of indoor green onion growing also avoids pest challenges, slugs, and other common pests from the garden.
Why regrow green onions?
There are several vegetables that can be grown, or re-grown from kitchen scraps. The tops of carrots can be planted to let you harvest carrot greens. Romain lettuce can be rooted, and grow a new partial head of lettuce. Even celery can have leaves re-grown. Scallions, or green onions, are one of the easiest kitchen scrap vegetables to re-grow.
Most grocery store green onions are still green onion plants. They still have some of their roots. Those roots will re-grow, and the easiest way to do it is in a jar of water. You’ll get lots of green shoots and green leaves from just six onions this way. And, you don’t have to buy any green onion seeds either, or worry about onion maggots.
How to regrow green onions
When you buy a clump of green onions from the grocery store, trim off the root end with about 1 inch of white. Use your green onions as usual in your soups and cooking.
Take a clean, pint sized, wide-mouth mason jar and place a support inside it. A hydroponic basket with a few pebbles works. There are special inserts for these size jars specifically made for onions now, they’re 3D printed. I’ve also just set the onion ends in a shallow bowl of water, with a few rubber bands across the bowl to hold them up. This only works if you don’t have a cat that likes knocking bowls over, though.
Add your water and your green onion root ends. Then, place the roots in a sunny spot. I like putting my jar under a grow light. However a sunny windowsill will also work well. Wait a few days and the onions should begin to lengthen, at least the green part. There won’t necessarily be new growth tips, but the greens will grow.
Change the water in your jar, or bowl, every few days. This depends on the temperature of your house. If you have a cool house, every four or five days should be good for water changes. If you have a warm house, every third day may be better. There is no need to wrap the jar, or to try to protect the roots from light. Though, if you want to wrap the jar to prevent algae growth you can. S
Once the onions are around six inches long you can take scissors and cut them back to about 1-1.5 inches high. Let them re-grow again. Since no plant food is being added to the water, the onion’s growth will slow down after 3-4 harvests. To keep the growth vigorous, you can add some hydroponic plant food, follow the kratky method if you’re growing in a jar. Or, you can take the 4 or so harvests, and then buy a fresh bunch of green onions and re-start your jar for another series of green onions.
New to growing baby green indoors?
Check out the Fill Your Salad Bowl workshop and learn how to use 3 different growing methods, at home, so you can fill your salad bowl with super food, nutrient dense, greens every single day. These are greens you can use in your salad bowl, greens you can add to soups, stews, and pasta dishes, and even greens you can use in a stir fry.
In this mini workshop you will learn how to fill a salad bowl every day with food you grow yourself.
- Even if you don’t have any land.
- Even if there is 3 feet of snow covering your garden
- Even if you’ve killed house plants in the past.
- Even if you think you have a black thumb.
Have a look at what’s covered in this workshop and see if its a good fit for you, by clicking/tapping the blue button below.