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When to Plant Green Onions? (How to Choose the Best Month)

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Green onions, also known as scallions, can be planted from seeds, started indoors and transplanted, or grown from onion sets. Knowing when and how to plant them is key to success.

Green onion seeds germinate when the soil temperature reaches about 45 degrees Fahrenheit, so the planting time depends on the weather of the area in which you live. But, by starting seeds indoors and transplanting seedlings or by planting onion sets, they can be planted later when the weather is warmer. 

Onion seedlings and onion sets can be planted outdoors when the weather is still cool, but not cold, and they produce best at 55 to 75 degrees Fahrenheit. In many parts of the country, green onions can be planted twice a year, spring and fall.

Below is a hardiness map of the United States, with average annual temperatures included:

Arbor Day Foundation Hardiness Map
Courtesy Arbor Day Foundation

For more in-depth and specific information about when to plant green onions in your particular planting zone, see the USDA Plant Hardiness Zone Map.

The USDA (United States Department of Agriculture) establishes and monitors plant hardiness zones depending on weather patterns over a certain period of time to aid growers, whether they are farmers, foresters, or just part-time gardeners in selecting and caring for plants that will perform the best in each particular region of the United States. The most recent Plant Hardiness Map issued by the USDA was in 2012 based on weather patterns from 1976 through 2005. 

Green onions grow best in plant hardiness zones 6 – 9, but are able to adapt to different growing zones. In fact, some varieties are cold hardy to -10 degrees Fahrenheit.

When To Plant Green Onions?

Starting Seeds IndoorsStart seeds indoors about 8 – 10 weeks before transplanting them in the garden right after the average last frost date. Onion seeds need temperatures of at least 50°F (10°C) to germinate properly. 
Transplanting Seedlings OutdoorsThe best time for planting onion seedlings outdoors is in the spring, right after the last frost. Place them about an inch deep in the soil, at least half an inch apart, in rows 1½ – 2 feet apart.
Planting Seeds OutdoorsPlant green onion seeds outdoors in the spring as soon as the ground can be worked.
For a fall crop, plant the seeds in late summer for harvest in late fall, early winter.
Planting Onion SetsPlant onion sets in the spring when the danger of frost is past, in March or April in most areas. It is best to time your planting so that outdoor temperatures no longer reach below 28 degrees Fahrenheit.Onions planted in the fall normally grow larger bulbs to harvest in the spring and need at least 4 to 6 weeks of warm temperatures so that the root system becomes established before winter. They remain dormant during the winter, but begin to grow as temperatures rise in the spring.

Notes on Planting Green Onions:

  • Plant seeds outdoors in early spring as soon as the soil can be worked and then again in the early fall. 
  • Green onion seeds need a soil temperature of a minimum of 45 degrees to germinate, although warmer is better.
  • In many locations, planting time for onion sets will be in April or May, depending on the climate.
  • You can plant onion sets as late as May 18th in most areas to still give your green onions 100 days of optimum growing time.
  • Green onion plants grow best when the temperature is between 68 and 78 degrees.
  • Green onions can thrive in humid conditions with good drainage to prevent rot and other diseases.
  • Green onions can be planted in spring and fall in most areas, and in the deep south can grow year-round.
  • Green onions require full sun and regular watering.
  • Add fertilizer with nutrients that are needed for your particular soil. The best way to determine your soil’s requirements is to have your soil tested by your local Ag Center. 
  • Always practice crop rotation.
  • Harvest green onions as they reach a usable size.
  • Dig up bunches of green onions when the stalks either die or produce flowers, trim and dry them, and separate the individual bulbs for onion sets to be planted during the next growing season.
Young woman in the garden with green onions

In Which Season Can Green Onions Be Grown?

  • In all except the coldest climates, green onions can be grown at least twice per year, spring and fall. 
  • In the coldest climates, they can be planted in the spring and harvested in late summer.
  • In very warm climates like the Gulf Coast region of the United States, green onions can be grown year-round.

Can I Plant Green Onions in April?

In most parts of the country, green onions can be planted in April from onion seedlings started indoors and from onion sets. And, in the extreme northern part of the country and in Canada, green onion seeds can be planted in April.

Can I Plant Green Onions in February?

In most areas, February would be the best time to start green onions indoors for transplanting later when the weather is warmer and the danger of frost has passed. And, in many areas where the climate is not extremely cold, February would be the best time to plant seeds directly into the garden outdoors for a late spring/early summer harvest.

Which Soil Is Best For Growing Green Onions?

While green onions will grow in a number of different soils, they prefer a fluffy, well-balanced, and loamy soil with a pH of between 6.0 and 7.0. The best soils are sandy loam, loams, and clay loam.

If your soil is poor, you can add a fertilizer with a 1-2-2 ratio such as 5-10-10, which means it contains 5% nitrogen, 10% phosphorus, and 10% potassium. To be more precise in adding the nutrients your soil needs, have your soil tested by your local AG Center.

Green onions have shallow roots, so the soil should be amended in the top 6 inches so that the plants can access the nutrients.

How Deep Do You Plant Onions?

Green onion seeds should be planted ¼ to ½ inch deep, and be sure to keep them moist, but not wet. 

Green onion seedlings. If starting green onions from seeds, when the plants are ready to transplant, dig a furrow 2 inches deep. Loosen the soil around the plants and gently dig them up. Trim the roots to ½  inch and the tops to 4 inches and plant them ½ inch deep, 2 – 4 inches apart.

Green onion sets should be planted 1 inch deep, 1 – 2 inches apart, in rows 12 inches apart

When to Harvest Green Onions

Green-Onions-in-a-Basket

Green onions can be harvested as soon as they reach a usable size, usually when the green stalk is at least as large as a pencil.

After green onions have gone to seed or when the green stem turns brown and dies, they can be dug up to dry for onion sets to plant in your next garden.

How Do You Select Green Onions?

Green onions are sold in bunches that will last in the refrigerator for up to two weeks. The stalks of the green onions should be firm and crisp, with bright green tops and white bulbs. 

If you are picking green onions, choose onions that are firm and crisp with vibrant colors.

Should Green Onions Be Washed Right After Being Harvested?

Green onions that you buy will more than likely already be relatively clean. When you are picking them yourself, however, they will need to be cleaned before storing them in the refrigerator.

To harvest them, gently loosen the dirt around the bunch and then hold the onions as close to the ground as possible and pull up the entire bunch. Remove as much of the dirt from the roots as possible, then separate the individual onions and trim the roots to just below the base of the bulb.

The green onions can then be wrapped in a piece of paper towel and placed in a plastic bag and stored in the refrigerator for up to 2 weeks. The green onions should be washed thoroughly and trimmed right before using.

How Can Green Onions Be Preserved?

Chopped Frozen Green Onions

Green onions can be preserved by either freezing, drying, or pickling them. Here is an overview of all three methods of preservation.

Freezing Green Onions

Green onions can be washed, dried, sliced, and spread in a single layer on a baking pan until completely frozen, and then poured into an airtight container like a freezer box or bag and stored in the freezer for up to 6 months, possibly longer depending on the container they are stored in.

Drying Green Onions

Green onions can be dried by one of three methods: Dehydrating, Oven Drying, or Air Drying.  

Dehydrating: 

  1. Wash the green onions and remove any layers that are broken or split.
  2. Remove the roots from the onions.
  3. Slice the green onions to the thickness that you prefer.
  4. Spread evenly over a dehydrator tray.
  5. Set the dehydrator at 125 degrees Fahrenheit.
  6. Process for 3 to 5 hours or until completely dry.
  7. Check to be sure the green onions are done. They are done when they break or crush easily. If they bend, they are not dried and should be processed longer.
  8. When cool, store in an airtight container like a Mason jar.

Oven Drying:

  1. To dry green onions in the oven, prepare the onions using steps 1 – 3 above. 
  2. Spread them in a thin layer on a baking sheet covered with waxed or parchment paper or aluminum foil. 
  3. Bake at 140 degrees Fahrenheit (or the lowest oven setting) until they are completely dry. Prop the oven door open just a crack during the baking process to allow for evaporation.
  4. Stir the onions every 30 – 45 minutes during the processing time. 
  5. Check them for doneness every 5 – 10 minutes.
  6. When completely cool, store in an airtight container like a Mason jar.

Air Drying:

  1. Prepare the onions using steps 1 – 3 above.
  2. Spread them in a thin layer on a baking sheet lined with waxed or parchment paper or aluminum foil.
  3. Set the pan of onions in a dry area free from drafts and stir occasionally until dry.
  4. The length of time this process takes will depend on the temperature and humidity in the house.
  5. Store dried green onions in an airtight container like a Mason jar. 

Pro Tip: Substitute dried green onions for raw green onions at the rate of 1 Tbsp dried green onions for 1/4 cup raw green onions.

Pickled Onions

Pickled onions are delicious as a quick snack or as part of a meal with corned beef, sausage, or meatloaf, and they are easy to prepare and make an excellent addition to your food supply pantry.

Here is a simple pickled onion recipe for you to try:

Ingredients:

  • 2½ pounds Green Onions, trimmed and cut into 3-inch lengths
  • 3 cups White Vinegar
  • 3 cups Water
  • 1½ Tablespoons Salt
  • 1 teaspoon Black Peppercorns
  • 1 teaspoon Celery Seeds
  • 1 teaspoon Mustard Seeds
  • 4 Whole Allspice Berries
  • 4 Pint Canning Jars with Lids and Rings

Directions:

  1. Prepare a boiling water bath.
  2. Prepare jars and sterilize for 10 minutes.
  3. Combine peppercorns, celery seeds, mustard seeds, and allspice berries in a small bowl and divide equally among the prepared and sterilized canning jars.
  4. Wash, trim, and pack the onions into the canning jars.
  5. Combine the salt, vinegar, and water in a saucepan and bring to a boil over high heat.
  6. Pour the hot liquid over the onions, leaving a ½ inch headspace.
  7. Wipe the jar rims and threads with a clean, wet cloth and affix lids and rings.
  8. Bring the water in the boiling water bath back to a full rolling boil and lower the jars into the boiling water bath, making sure the water level in the pot covers the tops of the jars by at least 1½ to 2 inches. Add water to the pot as necessary.
  9. Process the green onions for 15 minutes.
  10. Remove the jars to a prepared area and let stand, undisturbed, for 24 hours.
  11. Check the seal on the jars, wash and dry jars, label, and store in a cool, dry area.
  12. For the best flavor, wait at least 4-6 weeks before opening the pickled green onions.

How Long Do Green Onions Last?

  • Fresh green onions can stay good for 4 to 5 days if left unwashed and stored in a cool, dry area.
  • Fresh green onions can stay good for up to 2 weeks in the refrigerator if stored properly.
  • Green onions can be stored in the freezer for up to 6 months, possibly longer depending on the container they are stored in.

How Do You Prepare Onion Sets?

  1. When green onions have multiplied and then flowered and gone to seed, dig up the bunches of green onions, leaving the roots of the bunches intact.
  2. Remove as much of the dirt from the onions as possible in the garden.
  3. Trim the stems of the onions, leaving the roots with approximately 2 inches of onion. (Green stems can be used or stored for later use.)
  4. Spread the onions on a prepared surface, a box, a tray, or a baking pan, and store in a cool dry area to dry.
  5. When the next growing season comes around, separate the dried onion sets and plant either in pots or directly into the garden.

Are Green Onions The Same As Other Onions? 

Many people think that green onions are just regular onions that are picked before they are mature. However, green onions, which are the same as scallions, are a different type of onion that has a milder flavor and do not grow a large bulb like other onions.

How Can You Serve Green Onions?

Potato Soup with Green Onions

Green onions can be served with all types of food and are especially good served in the following ways:

  • Thinly sliced to garnish such foods as soups, stews, grilled meat, dips, potato and other salads, and deviled eggs.
  • Add green onions whole along with celery sticks and carrot strips to charcuterie trays.
  • Add larger slices to stir-fries and casseroles.
  • Chop and add to green salads.
  • Slice thinly and add to scrambled eggs and omelets.
  • Sliced as an ingredient in chicken, egg, and tuna salads.
  • Sliced as a topping for baked potatoes instead of chives.

What Is The Nutritional Value Of Green Onions?

According to the USDA, one medium raw green onion contains the following nutrients:

NutrientAmount Per One Medium Green Onion
Calories4.8 grams
Protein0.3 grams
Fat0.0 grams
Carbohydrates (Sugar)1.1 grams (0.4 grams)
Fiber0.4 grams
Calcium1% daily value
Iron1% daily value
Vitamin K34% daily value for women
Sodium2.4 milligrams
Vitamin C4% daily value

Because green onions have the benefits of onions as well as green, leafy vegetables, they are an excellent source of vitamin K, and one medium green onion provides 34% of the daily value of vitamin K for women. Plus, they are a good source of vitamins A, C, and folate.

Are There Possible Negative Effects to Eating Greens?

Eating raw green onions are known to cause gastrointestinal issues for many people including heartburn, nausea, vomiting, and abdominal discomfort.

Final Thoughts

My family in the southeastern part of the United States has always grown green onions twice each year, spring and fall. We leave some of the bunches from each crop in the garden to go to seed to save and dry to be used as “onion sets” for the next growing season.  As a matter of fact, green onions can be left in the garden all year round to continue to grow and multiply.

Even those of you who don’t actually garden might be interested to know that green onions grow well in pots and would provide an “edible garden” inside your home or on a porch that would provide you with a supply of fresh green onions year-round.

Thanks for stoppin’ by!

Jelly Grandma

For more, don’t miss Garden Vegetables Planting and Harvest Times (With Charts).

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