Onions are the unsung heroes of the kitchen, adding depth and flavor to a wide range of dishes. They are my absolute favorite ingredient and an essential addition to any home garden. If you’re an onion lover, you’ve probably daydreamed about cultivating your own supply of fresh, sweet onions. In this article, we’ll take you through the basics to plant onions from onion sets. There are no secrets or hidden tricks—just a few simple steps and a lot of love for onions.

Onion Plant Overview

Onions are a versatile and essential ingredient in many culinary creations. They come in various varieties, each with its own unique flavor profile, from sweet to pungent. Onions can be successfully grown both indoors and outdoors, making them an excellent addition to your garden or even a container on your windowsill.

What You Need

Indoor Growing:

  • A sunny windowsill or a grow light.
  • Containers or pots with good drainage.
  • Quality potting soil.
  • Onion sets or seedlings.

Outdoor Growing:

  • A sunny garden spot with well-draining soil.
  • Garden tools like a hoe and rake.
  • Compost or rotted manure.
  • Onion sets or seedlings.

How to Plant An Onion

Indoor Cultivation:

  1. Choose a sunny windowsill or provide artificial light for your onion plants.
  2. Plant onion sets or seedlings in containers with good drainage, using quality potting soil.
  3. Ensure the sets or seedlings are about 4 inches apart.
  4. Water your onions regularly, keeping the soil consistently moist but not waterlogged.

Outdoor Cultivation:

  1. Find a sunny garden spot with well-draining soil.
  2. Dig a trench about 8 inches deep, and use a rake to smooth the soil.
  3. Create rows with a hoe, ensuring they are not too deep.
  4. Mix compost or rotted manure into the soil.
  5. Plant onion sets or seedlings in rows, spacing them at least 4 inches apart.
  6. Keep the soil consistently moist but not waterlogged.

Tips for Successful Growth

  • Onions thrive in sunny locations, so choose a spot that receives direct sunlight.
  • Keep the soil consistently moist but not waterlogged.
  • Fertilize with compost or rotted manure to promote healthy onion growth.
  • Plant in early spring with the stem portion pointing up.
  • Allow room for onions to mature by spacing them at least 4 inches apart.

Harvesting Techniques

Harvest your onions when you notice the tops have dried out. Gently pull them out of the ground, being careful not to remove the entire stem. Place harvested onions in a shaded area for a few days to cure, then trim the roots and stems before storage.

To use the onions you’ve grown to make another onion, you can follow a process called “bulbing up.” Here’s how you can do it:

1. Select Onion Bulbs:

  • Choose healthy, fully matured onions from your harvest. These onions should have well-dried tops and a firm, dry outer skin.

2. Prepare the Bulbs:

  • Trim the roots and any remaining stems from the harvested onions.

3. Curing:

  • Place the selected onion bulbs in a cool, dry, and well-ventilated area for a few weeks. This process, known as curing, allows the onions to further dry and harden their outer layers, which is essential for storage and successful replanting.

4. Storage:

  • After curing, store the onion bulbs in a cool, dry place with good air circulation. This can be in a mesh bag, crate, or any container that allows air to flow around the onions.

5. Replanting:

  • When the next planting season arrives, you can replant the cured onion bulbs. Choose a sunny location in your garden or containers if you’re growing them indoors.
  • Space the bulbs appropriately, ensuring they have room to grow. Plant them with the root end down and the green stem end facing up.

6. Care and Maintenance:

  • Water your newly planted onion bulbs regularly, ensuring the soil is consistently moist but not waterlogged.
  • Fertilize with compost or organic fertilizer to support their growth.

Over time, the onion bulbs you replant will grow into mature onion plants, producing a fresh crop of onions. This process allows you to continue the cycle of growing your own onions season after season. Onions are biennial plants, so they will produce seeds and new bulbs in the second year of their life cycle, which can be saved and replanted for future harvests.

Additional Resources

For more information on onion cultivation, visit the following resources:

Check out our other How-To’s for vegetables here!