Tips on Growing Red Onions

While most of the onions used for cooking are yellow onions, the mild, sweet taste and attractive coloring of red onions make them a favorite for salads and colorful garnishing for many recipes. If you’d like to grow your own red onions, it’s easy, fun and economical, since red onions last for months in storage.


How Long Do Red Onions Take to Grow?

Planting red onions uses the same method as yellow onions. They’re biennials, which means they take two years to mature if planted from seeds. The easiest way to plant red onions is to use onion sets. These sets are second year bulbs that you can find at a garden store. Planting red onion sets will give you mature, red onions within three to four months from planting.

How to Plant Red Onions

Before planting your red onions, find a sunny location for your garden and test the soil for pH levels and nutrients. Once you know if your soil needs any adjustments, you can add nutrient-rich organic fertilizer to the garden soil to boost your onion bulb growth. Follow these steps for planting red onions:

  • Prepare the garden soil, removing all stones, weeds, roots and other debris.
  • Smooth out the soil with a stone rake.
  • Add organic fertilizer, if needed. Spread it into the soil with a garden rake.
  • Dig shallow, 1-2 inch furrows into the soil that are spaced about 2-3 feet apart.
  • Place the onion sets into the furrow about 3-4 inches apart.
  • Water the bulbs but not enough to form puddles.

When Are Red Onions Ready to Harvest?

Just like other onion varieties, red onions are ready to harvest when the bulbs grow large enough for you to see the onion tops pushing up from the soil. You’ll also notice that the onion stalks are turning yellow and tipping over. When this happens, your onions are ready to cure and harvest.

How to Cure Red Onions

Curing your red onions is a simple process. All you have to do is pull the bulbs out of the soil and allow them to dry for about two weeks. You can either leave them in your garden to dry, or gather the bulbs and place them in a dry, well-ventilated area. No matter which drying method you choose, make sure the bulbs have plenty of air circulation, so they don’t grow mold or fungus, which leads to rotting.

How to Store Red Onions

Once you cure your red onion bulbs, cut the dried onion stalks about 1 inch from the top of the bulb. Place the bulbs in containers that allow exposure to the air, such as mesh bags, slatted wooden tubs or paper bags with punched holes that allow air circulation. Place the storage containers in a cool, dry place between 32° (0°C) to 50°F (10°C).