Plan the perfect garden with our interactive tool →

How to Grow Red Onions From Bulbs

...
Jenna Winkeller/Demand Media

Red onions can be eaten raw, boiled, broiled, baked, creamed, steamed, fried or pickled. These cool-season vegetables are grown by gardeners either from seeds or from small bulbs. Onions are biennial plants that take two years to complete their life cycle. When planted from seed, the red onion forms and above-ground steam--modified leave --and tiny underground bulbs. The next year, larger bulbs form until the red onions are mature and ready for harvest. Planting small red onion bulbs, known as onion sets, allows gardeners to bypass the first year of growing and harvest mature onions much more quickly.

...
Jenna Winkeller/Demand Media

Loosen the soil to the depth of 6 inches with a shovel two to four weeks before the last frost date. Till the soil until it is loose and ready for planting. Add 2 inches of compost to the soil to ensure good fertility.

...
Jenna Winkeller/Demand Media

Plant the red onion sets 1 inch deep and 2 to 4 inches apart. Cover them with soil, but do not compact the soil. Plant additional rows of onions 12 to 18 inches apart.

...
Jenna Winkeller/Demand Media

Weed the onion patch by hand. Red onions have shallow roots and do not grow well among weeds and grass, which compete for soil nutrients and moisture. Use a garden hoe to eradicate the weeds between the rows.

...
Jenna Winkeller/Demand Media

Water the red onion bulbs each week whenever the weather is dry. Water the soil around the base of the plants until the soil is moist to depth of 2 to 4 inches, depending on the size of the bulbs. Use a 1-inch layer of straw mulch around the red onion bulbs to suppress weed growth and hold in soil moisture.

...
Jenna Winkeller/Demand Media

Feed the red onions three weeks after active growth has started. Place a narrow band of 10-10-10 slow-release fertilizer 2 to 3 inches beside the row of onions. Scratch it into the top 1 inch of soil and water right away to start the fertilizer working. Use about 1 lb. of fertilizer for every 100 square feet of planting space.

...
Jenna Winkeller/Demand Media

Pull every other onion when harvesting for the first time. This allows the red onions left in the garden more room to grow. Harvest the onions on a dry morning. Let the onions dry for the day in the shade. Later, braid the tops together and hang the red onion bunches in a cool, dry area with good air circulation.

Tip

Separate the red onion sets by size. Make two piles: onions smaller than a nickel and larger than a nickel. The larger bulbs tend to bolt before growing into full-sized onion bulbs. It is best to harvest these bulbs early as green onions.

Warning

Purple blotch and Botrytis leaf blight are two plant diseases that infect red onion plants. These diseases are caused by wet leaves. Water the red onions early in the day so the leaves will dry before night. Remove the infected plant parts when the plants are dry.

Related Articles

How to Harvest Red Potatoes
How to Harvest Red Potatoes
How to Plant and Care for Texas Supersweet Onions
How to Plant and Care for Texas Supersweet Onions
When to Plant Red Potatoes in Mississippi
When to Plant Red Potatoes in Mississippi
How to Plant Onion Sets
How to Plant Onion Sets
How to Plant Onion Bulbs in the Spring
How to Plant Onion Bulbs in the Spring
How Long Does it Take Red Radishes to Grow?
How Long Does it Take Red Radishes to Grow?
How to Grow Onions From Bulbs
How to Grow Onions From Bulbs
How to Care for Red Yucca Plants
How to Care for Red Yucca Plants
Onion Plants
Onion Plants
How to Plant Onions in Colorado
How to Plant Onions in Colorado
How to Transplant Allium
How to Transplant Allium
How to Grow Pearl Onions
How to Grow Pearl Onions
How to Plant & Grow Walla Walla Onions
How to Plant & Grow Walla Walla Onions
How to Plant Onion Sets in Florida
How to Plant Onion Sets in Florida
List of Onion Varieties
List of Onion Varieties
How to Make Grass Grow in Red Dirt
How to Make Grass Grow in Red Dirt
How to Transplant Amaryllis
How to Transplant Amaryllis
Growing & Harvesting Red Kidney Beans
Growing & Harvesting Red Kidney Beans
Garden Guides
×