Onion Types

Onions (Allium cepa)

Common onions constitute the vast majority of commercial crops and form single bulbs. They include common, dry bulb onions, and salad and pickling onions.

Bulb shape, color and leaf characteristics vary markedly within this group. In practice they are categorized according to the daylength needed to stimulate bulb development. There are the short ones (12-13 hours) and the intermediate or long (14-16 hours) daylength varieties. 

Types include "Sweet Onions", "Spanish Onions" and "Dutch Onions".

Aggregatum onions form clusters of bulbs and include shallots, which have pods similar to garlic and reddish brown skin surrounding a bulb that has subtle flavors of both garlic and onion.

Shallots have a very high dry matter content - between 16 and 35% - compared to 7-15% for onions.

As with onions there are many different types of garlic with a range of different numbers, sizes, shapes and colors of cloves with a wide spread of cold hardiness characteristics and bulb dormancies.

Leek, Kurrat, Great Headed Garlic and Pearl Onions (Allium ampeloprasum) 

Leeks produce long, concentric leaf sheaths in a flat fan form, and long, white edible pseudostems. They vary according to the potential length and diameter of the pseudostem and rarely bulb. They are largely grown in temperate regions throughout Europe and parts of North America.

Kurrat is characterized by a short pseudostem with edible leaves and is largely restricted to North Africa. These leaves are harvested regularly through the season. 

Great Headed Garlic looks like a large, vigorous garlic plant and produces a flower like those in leeks. It is largely grown in Asia and North Africa. 

Pearl Onions are largely garden crops in Germany and Holland. They are like small leeks but develop to form a cluster of small spherical, white bulbs. 

Japanese Bunching Onion – (Allium fistulosum) While similar to common onions, Japanese bunching onions don’t form dormant bulbs. They are largely grown in China and Japan.

Rakkyo – (Allium chinense) produces small edible grey, white or purple bulbs for pickling. They are largely grown in China and Japan. 

Chives – (Allium schoeniprasum) are grown for their green onion flavored leaves across a wide range of countries, this coldhardy allium forms dense clumps of low growing, narrow plants with hollow leaves. 

Chinese Chives – (Allium tuberosum) Cultivated for its edible garlic flavored leaves and young flowers, Chinese chives are largely grown in East Asia.