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How To Grow Bunching Onions In A Container? [Updated 2024]

Do you know that growing Bunching Onions in a container allows unrestricted subsurface root growth and moisture for the plantlets? 

To grow Bunching Onions in a container, buy 6-12 inches deep plastic, terracotta, ceramic planter, or a deep seedling tray with drainage holes. Then, fill it with well-draining soil and plant the seeds about 1/4th inch deep and 1 inch apart in groups.

Learn how to grow Bunching Onions in containers and follow some tips to prolong their harvest.

Can You Grow Bunching Onions in Containers?

Evergreen Bunching Onions, also called Green Onions or Scallions, are regular onions in their early growth stage with smaller bulbs.

You can grow the Bunching Onions in sizeable containers (plastic, clay, terracotta, or ceramic), where they multiply to form clumps.

Containers are ideal as Bunching Onions have thin fibrous roots that cannot spread to greater depths under the soil.

Image shows thin root system of bunching onions
Bunching Onions have a thin, delicate root system that cannot enter greater soil depths.

However, some additional favors you can gain from growing Bunching Onions in containers are as follows.

  • The small area in the containers holds the nutrients aiding the short roots of onions to grab them.
  • Estimating the amount of water and fertilizer is easy in small planters than in the open ground.
  • Harvesting these perennials from a small container patch rather than the garden is painless.
  • They form small underground bulbs. So, they rarely require vast belowground soil space.

Best Time to Grow Bunching Onions

Winter (December-January) is the accurate time to cultivate Bunching Onions for a lengthy harvest.

Image represents the placement of bunching onion divisions indoors in winter
Start Bunching Onion seeds indoors in pots in winter and transplant them later in warm soil.

After planting Bunching Onion seeds in a pot or container, you can reap them in late spring to early summer (May-June) when the flowers fade to brown.

However, you can also plant the seeds in late summer to get garden-fresh Bunching Onions as fall or spring comes by.

Another way is to start the seeds indoors mid to late winter (5-6 weeks before the last frost).

This way, onions can have long-lasting foliar growth after transplanting them outdoors in spring (March). 

How Long Do Bunching Onions Take to Grow?

Germination may initiate around 1-2 weeks on warm, well-draining soil saturated with moisture.

Image represents the seedlings of bunching onions in a starter tray
Bunching Onions can readily germinate with the right soil temperature and humidity levels.

But, it may take 2-4 months to see well-yielding onion clumps in your garden.

To encourage regrowth, cut their leaves once they reach about 30 centimeters, and they will retain new foliage within 1-3 weeks.

Bunching Onions [Growth Requirements]

You can grow as many onion clumps as possible, but the containers must be spacious enough for the roots to roam freely under the soil.

Likewise, the substrate must blend the correct and appropriate amount of components.

1. Container for Bunching Onions

Several planter alternatives exist, like terracotta, plastic, and ceramic pots.

But, the containers for Bunching Onions must be around 6-12 inches deep with basal drainage holes and considerable width.

Check the table to know which containers you can use to grow Bunching Onions.  

Caribbean Plastic PlantersLight weight with considerable brim width

Drainage holes with detachable plug

Dimensions: 8.25"×8.25"×6.75"
Terracotta PotsDrainage holes with saucers at the base

Lightweight but sturdy

Dimensions: 6.5"×6.5"×6.5"
Sunnydaze Ceramic PotsStrong and durable with glazed finish

Frost-proof and with a drainage hole at the base

Dimensions: 11.75"×6"×9.5"
Seed Starter TrayExtra cup space for larger seedlings

Comes with a humidity dome to preserve the humidity for germinating seeds

Drainage hole present at the bottom of each cup
Flexible Plant Nursery PotsFlexible pots with spacious depth for root growth

Ample amount of drainage holes at the bottom

Dimensions: 6.7"×5.1"×6.9"

2. Soil for Bunching Onions

Use a well-draining, sandy, loamy, fluffy, organically rich, and water-retaining soil with low pH (5.5-7).

Image represents the soil used for growing bunching onions
Bunching onions prefer well-draining, moisture-retentive, and organically rich soil.

The soil must also be fluffy so the roots can willingly grow without hindrance.

Mix 1 part compost (cow dung), 2 parts normal garden soil, 3 parts sand, and 3 parts filler (decaying vegetables, coffee grounds, or coconut fiber).

Add water to mix it thoroughly so that the mixture stays evenly moist, and common household compost is also a good choice.

Check the table below for an idea about some commercial starter mix for the onions.

Seed Starting MixesSpecifications
Sun Gro Horticultural Seed StarterContains a mix of peat moss, perlite, dolomite lime, and organic agent
Espoma Organic Seed Starter MixContains a supreme blend of peat moss, perlite, yucca extract, and lime

Also has ecto and endo-mycorrhizae for root growth
Premier Horticulture Organic Pro Seed StarterContains coconut fiber for optimal root growth and rot protection

Slow release of amended nutrients
Miracle-Gro Seed Starting Potting MixEasy to root cuttings from leaves, stems, and bulbs

Easy to start the seedlings for most veggies
Purple Cow Organic Seed StarterRapid induction of germination

Extra cow compost for faster germination

How to Grow Bunching Onions in A Container?

You can grow Bunching Onions in containers using seeds or stem divisions.

Both methods are easy and reliable, ensuring fresh Green Onions every season.

1. Bunching Onions from Seeds

Seeds may be labeled as “scallion seeds” in your area.

Another choice is to harvest fresh seeds from the plants.

Collecting Bunching Onion Seeds

To collect the seeds, you can follow these steps.

  • The flower heads turn brown and papery during late spring to early summer, with black, shield-shaped seeds.
  • Using sterilized pruners, cut the flower heads from the base and separate the seeds from the husk.
Image represents the dried flowers of bunching onions
Extract the seeds from Bunching Onion flowers after the ivory-white flower heads turn brown and fade.

Sowing Bunching Onion Seeds

Mid to late winter is the perfect time to sow Bunching Onion seeds.

It aids in the early establishment of the seedlings and hardens their roots during the transplanting process in spring.

You can follow these tips when the right time approaches to sow the seeds.

  • Take containers or a 6-12 inches deep seed tray.
  • Fill the pots or trays with the readymade potting soil or fill it with a common starter mix.
  • Using chopsticks, dig up about 1/4th inch deep holes at 1 inch apart.
Image shows the process of sowing the seeds of bunching onions
Bunching onion seeds require humidity, proper soil depth, temperature, and plenty of moisture to germinate right on time.
  • You can plant about 3-5 seeds in each hole and cover lightly with soil.
  • Moist the soil fairly with water and place the containers over a heating pad maintained at around 59-68°F.
  • Cover the containers with plastic wrap to maintain a warm and humid environment.
  • Locate the set-up near an east-facing window.

It will take the seeds about 1-2 weeks to germinate. Give them 4-6 hours of daily sunlight once the seedlings sprout.

For planting Bunching Onion seeds in a large container or ground, place 3-5 seeds in each hole about 9 inches apart or sow individual seeds in each hole about 4-6 inches apart.

After the seedlings sprout new leaves and become 3-4 inches tall, transplant them into the garden soil.

You can check the video below to revise the process of planting and growing Bunching Onions from seeds.

Planting Bunching Onions in Containers/ Ground

Bunching Onions requires transplanting to a bigger pot or warm ground to reduce the danger of root plugging.

They also require slightly wide legroom space for root growth to roam freely in the soil with each step.

You can begin transplanting when the ground temperature reaches around 59-68°F.

  • Border a required garden patch using wooden planks and amend the area with the homemade mix to a foot depth.
  • Prepare rows of soil about 9 inches apart using a gardening trowel.
  • Gently uproot the seedlings from the containers and transplant them along the row length. 
Image represents transplanting the seedlings of bunching onions in ground
Transplant the seedlings of Bunching Onions along the row length on open and warm ground in spring.
  • Then, firm the soil around the onion roots to hold the seedlings in their place.
  • The seedlings need to be 4-6 inches apart in each row.
  • Apply a thick layer of mulch at the topsoil to suppress the weed growth around the seedlings.
  • Water the seedlings when the soil is dry, and harvest after the foliage reaches about a foot long.

After this, the seedlings will focus their energy on showing rapid root development rather than using their energy for foliar growth.

2. Bunching Onions from Divisions

You can start a new Bunching Onion batch by planting onions from their divisions.

Here are the following steps for dividing and replanting your Bunching Onions.

  • Choose the right time in spring or summer when the leaves are about a foot long.
  • Uproot the clumps with your hand and separate the plants at the root ends.
  • Replant it in the same manner as you do for the seedlings, ensuring a sufficient distance between the mature plants.
Image shows fresh harvest of bunching onions
Separate individual Bunching Onion plants from the clump and replant them as divisions.
  • Dividing and replanting will be easy if the seedlings are 3-4 inches tall, as the roots can easily regrow.
  • Water the plants after the transplant to evenly moisten their roots.
  • Also, apply some more mulch to cover the topsoil.

Harvesting Bunching Onions

Bunching Onions are used for soups, fried dishes, stews, etc., fresh after harvest.

When the leaves become slender, they arch and flop over the ground, indicating that the plants are ready to harvest.

Additionally, 3/4th of the plant leaves turn bright green with a darker hue at the leaf tips when the onion meets the harvesting period. 

Image represents harvested bunch of bunching onions
The best time to harvest the Bunching Onions is when their leaves become a foot long.

You can follow the steps below to ensure a successful harvest.

  • Dig the onions from the bottom using a trowel and pull out the clump.
  • After harvest, place the Onions in a tray and wash under the sink water to remove the attached soil.
  • Finally, refrigerate the Onions or use them fresh on any dish you prepare.

Tips to Care for Bunching Onions

Bunching Onions may seem delicate, but they are hardy and drought-tolerant.

However, you can ensure a healthier harvest with minimal care from seedling to maturity.

  • Use 0.016 liters of water for each plant in the clump. Follow-up watering by giving a “finger depth test.”
  • Feed the plants with a high-nitrogen liquid fertilizer about 3 weeks after planting and continue the application once every 2-3 weeks until harvest.
Image represents the process of covering the topsoil with leaf mulch in winter
Mulching the Bunching Onions at the topsoil with leaves helps protect their winter roots.
  • Mulch the topsoil in winter to warm the roots. Remove it once the ground warms become feasible in spring or summer.
  • Invest in neem oil to deter pest or disease infestation and trim off yellow or brown foliage.
  • Continue growing the Bunching Onions indoors under grow lights for 10-12 hours daily in winter.

From Editorial Team


Bunching Onions in a container can easily grow throughout USDA zones 3-9, where the outdoor sunlight can directly furnish the plant.

Also, choose the right container with considerable depth and drainage holes that can retain moisture.

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