Green Onion Growth Stages

Understanding green onion’s life cycle will help you be a better gardener. What growth stages does it go through?

Green onions are one of the most used vegetables when cooking. Its tender stalks and leaves are harvested for its mildly sweet onion flavor.

Green onions are perennial plants and are grown more for their edible greens and stems than for their bulbs.

This vegetable matures quickly and can be harvested in 60 – 80 days. Although they can grow to be 3 feet tall, they are usually harvested when they are a foot tall.

It’s crucial to understand the lifecycle of green onions if you’re planning to include green onions in your vegetable garden. In this article, we’ll shed some light on this vegetable’s growth stages and share care instructions so that you can maximize its growth.


Germination can begin anywhere between 7 – 14 days.

The first sign of germination is the emergence of the radicle, which anchors the seed to the soil. The radicle begins absorbing moisture and nutrients from the soil to help the plant develop.

The cotyledon emerges next, and the growing seedling undergoes the “loop stage,” in which the cotyledon grows upward and forms a loop while the seed coat remains underground. The cotyledon serves as the young plant’s primary source of nutrition before its true leaves appear.

When the green onion’s first true leaf emerges, it resembles a miniature version of the mature plant’s flat, green leaf. True leaves can undergo photosynthesis and generate food for the growing plant.

The cotyledons will start to deteriorate as the true leaves continue to grow.

onion leaves staring to grow


At this stage, the small green onion plant begins to build its root system. The seedling produces more roots and a few more adult leaves before initiating rapid vegetative growth.

During the vegetative development stage, the green onion plant gradually goes from having a few thin leaves to having around 10.

At this stage, the plant resembles a typical green onion and can be harvested, although the flavor will be milder than that of mature onions.

growing onion leaves planted in rows


After 70 – 90 days, green onions are fully mature and ready to harvest. Green onions reach optimal growth right before they reach maturity — when the bulbs are just starting to develop and the tops are the width of a pencil.

Green onions can still be picked after that, but mature green onions have a spicier flavor.

Instead of cutting the top leaves and leaving the roots in the soil, it’s best to pull the whole plant and replant it with seeds. Harvests from old roots are often thinner and less abundant.

spring onions ready to harvest


Green onions bloom in their second year of life; this is an excellent time to collect seeds.

After the vegetative growth stage, each plant grows one or more flowering stalks that produce clusters of small flowers.

Self-pollination is common among green onion plants; however, cross-pollination may occur and is encouraged.

As the soil’s temperature rises, the plant starts to bolt, which means it suddenly sprouts a flowering stalk.

Once the stalk has fully matured, flower buds form and white or purple flowers bloom. The flowers turn light gray and open, displaying black seeds. Once the blossom has dried fully, the seeds will fall out.

Dried seeds can be kept for a few years or until you’re ready to plant new green onions.

a plant with blooming flower
Alaine Connolly
Alaine has been working way too hard in horticulture since 1992, beautifying golf courses, resorts, and hotels. She is a part time landscape designer who works full time caring for a 28,000 square foot public garden. At home, she maintains her own 400 square feet plot. Alaine lives in northern Illinois - zone 5b.
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