Vegetable Gardening and Onions

Onions grow underground and can grow during colder weather than most vegetables.

Many people with vegetable gardens grow onions because of their many culinary uses, cold weather tolerance, health benefits and long shelf life. Onions come in different types, with different sizes, colors and flavors. They contain no fat, are low in calories, provide dietary fiber and have several vitamins, including vitamins C and B6. Research also shows that onions contain chemicals that lower blood pressure and cholesterol, according to the National Onion Association.

Growth

The part of the onion you usually eat grows underground as a bulb. You can also harvest and eat immature onion stalks, called green onions. Onions can grow from seeds, transplants from gardening stores or nurseries or from onion bulbs that grew from seed during the previous year. Onion bulbs either produce new underground onion bulbs as they grow or produce new small bulbs on stalks above ground.

Types

Onions come in "long day" and "short day" varieties. Long day varieties only start to grow bulbs instead of stalks after daylight reaches a duration of 14 to 16 hours, while short day varieties start growing bulbs instead of stalks when daylight lasts from 10 to 12 hours. Long day onions grow better in the Northern U.S., while short day onions grow best in the Southern U.S. Onions also vary by color, size and flavor. For example, Walla Walla onions are large and have a sweet flavor, red onions are smaller with a slightly stronger flavor, and yellow onions are medium-sized with a very pungent flavor.

Planting

In relatively warm areas, plant short season onions during mid- to late-October, according to Texas A&M University. You will have green onions ready in a couple months or large onion roots ready for harvest in the spring. In cooler northern climates, plant onion bulbs during the spring after the last frost. Onions prefer soil with good drainage and at least moderate amounts of nutrients. The National Gardening Association suggests either tilling compost or manure into the soil or using a balanced fertilizer before planting.

Care and Harvesting

The University of Illinois Extension recommends weeding the garden where onions grow. Weeds take moisture and nutrients out of the soil, resulting in less nourishment for the onion plants. Green onions are ready for harvest after they reach 6 inches tall. Harvest onion bulbs when their green tops start to fall over.

References

• University of Minnesota Extension: Growing Onions
• Texas A&M University Horticulture: Onion Planting
• Alabama Cooperative Extension System: Growing Onions
• University of Illinois Extension: Onion
• National Gardening Association: Onion Essentials

Resources

• National Onion Association: About Onions--Onion Nutrition