Allium (Onions & Garlic) Bulbs

Produce tasty crops and make great garden companions

Allium is a diverse genus that contains approximately 800 species of bulbous herbs, which include a few common vegetables, such as onions and shallots (A. cepa), garlic (A. sativum), leeks (A. ampeloprasum) and chives (A. schoenoprasumand). These plants produce linear or cylindrical leaves that get about 2 feet tall and have a pungent smell when crushed. The number and size of the leaves determines the size of the bulb. For instance, each leaf of an onion represents one ring on the bulb, the larger the leaf, the larger the ring.

Alliums are sensitive to daylength, with bulb formation beginning when a certain day length is reached. Long-day plants begin bulb initiation when daylength reaches 14-16 hours. They grow best in northern states (latitudes of 37-47°) and typically produce the largest bulbs. Intermediate-day / day-neutral plants begin bulb initiation when daylength reaches 12-14 hours. They grow best in Zones 5 and 6 (latitudes of 32-42°) but produce well in almost any region, regardless of daylight hours, except the Deep South. Short-day plants begin bulb initiation when daylength reaches 10-12 hours and grow best in southern states (latitudes of 25-35°). They will grow in northern states but will not get very large.

Alliums make great companion plants. They repel garden pests, like aphids, slugs, snails, and even deer and rabbits; and some set charming pom-pom flowers that attract pollinators and beneficial insects, which help to produce healthier harvests.

Although alliums can be grown from seed, sets are the easiest and quickest way to grow them. Partially formed bulbets, sets quickly develop into full-size bulbs after planting. Sets tend to produce stronger, more vigorous plants compared to seed, ensuring larger yields.