This article was last updated by on

Ultimate Guide to Growing Bunching Onions in Container

Bunching Onions are more feeble in taste than bulb onions, and you can use them in salads or mix them with vegetables.

However, unlike regular Onions, you can grow Bunching Onions close to one another and prevent bulb formation. 

For growing Bunching Onions in containers, procure 6-12 inches deep plastic, terracotta, ceramic pots, or a large seed tray with drainage holes. Plant the seeds about 1/4th inch deep and 1 inch apart in groups in well-draining soil.

Stand by to learn growing Bunching Onions in containers and follow some tips about caring for them properly.

Reasons to Grow Bunching Onions in Containers

You can also grow the Bunching Onions in garden beds, where they will sprout in a bunch and multiply to form clumps.

Containers are preferable as Bunching Onions have a delicate, thin, and fibrous root system 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.

Here are some additional favors you can bring out for growing Bunching Onions in containers.

  • The small area in the containers helps hold the nutrients in the soil so that the short roots of onions can easily grab them.
  • Estimating the amount of water and fertilizer is easy in small planters than in the open ground.
  • Bunching onions are perennials that beget new leaves each season, so harvesting them from a small patch rather than garden-fresh is painless.
  • Bunching onions refrain from forming large underground bulbs like other onion varieties. So, they rarely require vast belowground soil space.

What is the Best Time to Grow Bunching Onions?

Planting onion stem divisions has no fixed season, but winter (December-January) is the supreme time to cultivate them for prolonged 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.

If you grow Bunching Onions from seeds, you may harvest them in late spring to early summer (May-June) after 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.

It may take 2-4 months to see harvestable onion clumps in your garden.

However, to encourage onion growth, you can cut their foliage after they reach about 30 centimeters, and they will retain new foliage in 1-3 weeks.

Requirements For Growing Bunching Onions in Containers

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.

Best Container for Bunching Onions

For outstanding crop growth, choose pliant containers for the onions.

Several alternatives include clay, terracotta, plastic, and even ceramic pots.

But, the containers must be around 6-12 inches deep with a fair number of drainage holes and considerable brim 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"

Best Soil for Bunching Onions

Use a well-draining, sandy, loamy, organically rich, and water-retaining soil low in pH (between 5.5 and 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.

Grab 1 part compost (cow dung), 2 parts normal garden soil, 3 parts sand, and 3 parts filler (decayed veggies, coffee grounds, or coconut fiber) and blend them in a container.

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

Growing Bunching Onions in Containers

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

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

1. Growing Bunching Onions from Seeds

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

Another choice is to harvest fresh seeds from the plants. You can do it with a patch of flowering Bunching Onions.

Tips for Harvesting the Bunching Onion Seeds

To collect the seeds, you can follow these simple steps.

  • The flower heads turn brown and papery from late spring to early summer, with black, shield-shaped seeds peeping from the top.
  • Using clean pruners, cut the flower heads from the base and separate them 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 transplanting in spring.

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

  • Wear protective gloves and take pots 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 a distance of 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 15-20°C.
  • 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.

You can also grow the plants directly in the ground after winter. To do this, 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.

Transplanting the Seedlings

Bunching Onions require transplanting to halt the danger of root crowding in planters.

Bunching Onions require slightly wide space for their roots to roam freely in the soil with each growth.

You can begin transplanting when the ground temperature reaches around 15-20°C.

  • 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 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.
  • 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. Growing 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 Onion 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 catch up with the growth.
  • Water the plants after the transplant to evenly moisten their roots.
  • Also, apply some more mulch to cover the topsoil.

Harvesting Bunching Onions

You can learn the harvesting time of the Bunching Onion if leaves become slender and later arch and flop over on the ground. 

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 a clump. 
  • Consider watering next time when the soil dries up to an index finger knuckle depth by giving a “finger depth test.”
  • Start feeding the plants with a high-nitrogen liquid fertilizer about three weeks after planting and continue the application once every 2-3 weeks.
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.
  • In winter, place a straw or leaf mulch over the topsoil to warm the roots. Remove it once the temperature becomes feasible in spring or summer.
  • Invest in Pyrethrin to deter any obvious pest or disease infestation and trim off yellow or brown foliage.

You can also continue growing the Bunching Onions indoors after germination under grow lights for 10-12 hours daily in winter until spring.

From Editorial Team


Bunching Onions grow in USDA zones 3-9, where direct sun can furnish the plant.

Choose the right container with considerable depth and drainage holes.

On top of that, proffer the seedlings with nurturing of proper soil.

Leave a Reply

Your email address will not be published. Required fields are marked *

You May Also Like