Onion Blooms: The Inflorescence

Onion plants produce a flower cluster, or inflorescence, consisting of numerous small flowers.

In our last post, we explored the onion plant’s unique flowering process, where a tall, hollow stalk (scape) emerges from the center, topped with a conical bud enclosed in a protective spathe. Inside the bud, hundreds of tiny flowerets await their turn to bloom.

Slowly the onion’s protective spathe gives way as buds mature, bursting open to reveal the emerging inflorescence. Over 5-6 days, the buds unfurl, standing tall with the empty spathe providing base support (picture 4).

After a few days, the flowers begin to bloom, adding a vibrant touch to the plant.

The onion’s flower cluster, or umbel, is supported by a sturdy stalk called the peduncle or scape. This umbrella-like structure consists of tiny stalks (pedicels) holding hundreds of small flowers (florets), often over 200! The term ‘umbel’ originates from the Latin word ‘umbra’, meaning shade or shadow, reflecting its umbrella-like shape.

Each delicate flower on the inflorescence featured, 6 white petals with green stripes, 6 stamens (anther and filament), and a central pistil (stigma, style, and ovary), all supported by slender pedicels.

What Secrets Lie Within?

When I dissected an onion floret, I was amazed to find a three-celled ovary, each cell containing two ovules. This intricate design reveals the potential for seed production in each delicate flower.

Onion Floret’s Ovary. We didn’t notice the onion floret’s ovary had three cells until we dissected it. This tiny detail reveals the intricate design of the flower.

A. Initial bloom

B. Buds awaiting bloom

C. Full bloom

D. Gradual drying

Onion seeds are usually ready to harvest after the inflorescence dries out, which takes about two to three months.

However, we couldn’t wait that long and collected 2-3 inflorescences after a month. Despite the seeds being slightly damp and brown, we were thrilled to see them.

A month later, we collected the remaining flower clusters and gently crushed each floret to release mature black seeds, marking a successful seed harvest.