How to plant onions?

Onions are versatile and flavorful vegetables, widely used in a variety of culinary dishes.

If you're thinking about growing your own onions, there are some important considerations to keep in mind.

In this guide, we’ll share helpful tips on how to plant, grow, and harvest onions to ensure a successful harvest.

Should I grow onions from seeds or sets?

When starting to grow onions, you have two main options: planting from seeds or use onion sets.

Planting onion seedlings, i.e. sets, is generally preferable as they establish more quickly and are easier to plant.

Onion sets are small onions that mature in about 14 weeks.

They have a higher success rate compared to planting seeds or transplants.

Additionally, the sets can tolerate light freezing.

When choosing onion sets, opt for those with bulbs approximately 2 inches in diameter, as larger ones tend to produce stiff necks and may go to seed.

However, growing onions from seeds is also feasible and may be necessary in colder regions.

Onions grown from seed require soil temperatures of at least 50°F (10°C) to germinate, which means they should be started indoors about 6 weeks before transplanting into the garden.

If you decide to try this method, check out our specific tips for growing onions from seeds.

Practice crop rotation with onions

It is important to practice crop rotation when planting onions.

Avoid planting them in the same place in your garden year after year, as this can encourage the spread of diseases that affect the crop.

Crop rotation is an effective practice for maintaining soil health and reducing the spread of pests and diseases.

By rotating planting areas, you help ensure healthy growth for your onions.

Growing Onions: From Planting to Harvest

Now that you understand planting options and the importance of crop rotation, let's explore the process of planting and growing onions.

Sowing Seeds in the Garden

When planting onions from seed, you will need to follow a few essential steps to ensure success:

• Select a sunny location: Choose a spot in your garden where the onions will receive full sunlight.

They need a lot of solar energy to grow and develop good-sized bulbs.

• Prepare the soil: In the fall or early spring, mix aged manure or compost into the soil to improve its texture.

Be sure to remove rocks and debris, as well-drained, loose soil is essential for healthy onion growth.

• Determine the right time for planting: In spring, plant onions outdoors as soon as the soil can be worked, which is usually in late March or April, when temperatures should not drop below -2°C.

• Prepare the seeds or sets: If using seeds, sow them in trays or containers filled with moist soil and place them in a warm, well-lit area.

Keep the soil moist and once the seedlings are about 6 inches tall they are ready to transplant.

If using sets, select those with bulbs approximately 2 inches in diameter.

• Plant the onions: To plant onion sets, bury them 2 to 6 inches apart, gently pressing them about 1 to 2 inches deep into the loose soil.

Make sure to place the bulbs with the tip facing up.

If transplanting seedlings, space plants 4 to 5 inches apart and rows 12 to 18 inches apart.

Avoid burying onions too deeply as this can affect the development of the bulbs.

• Additional care: To help retain soil moisture and control weed growth, cover the space between rows with straw.

Remove any onions that begin to send out flower stalks, as this indicates that the bulbs have stopped growing.

These onions do not keep well, but can be used in recipes in the next few days.

Growing Onions: From Growing to Harvesting

Once your onions are planted, it is important to provide them with proper care as they grow until harvest.

Here are some guidelines to help you through this process:

• Provide nutrients: Onions are plants that require constant nutrition to produce large bulbs.

When planting, add nitrogen fertilizer to the soil.

Many organic gardeners also add about an inch of compost to the bottom of each row before planting.

• Follow the growth: As the onions grow, monitor their development.

During the growing season, water regularly to keep the soil moist, but avoid waterlogging.

Remember that onions do not like soggy soil.

Final Considerations

Growing onions at home can be a rewarding and tasty experience, offering the satisfaction of eating fresh vegetables straight from your garden. Here are some important things to consider as you go along:

• Choosing the Planting Method: Deciding between seeds and sets is crucial. Sets are generally easier and faster for beginners, while seeds may be more suitable in cold climates.
• Soil Preparation and Planting Site: Selecting a sunny location and preparing the soil properly are essential for success. Well-drained soil, free of rocks and enriched with compost, will provide the onions with the ideal environment to grow healthily.
• Crop Rotation: Crop rotation is a key practice for preventing disease and maintaining soil health. By rotating your planting areas, you help ensure vigorous growth of your onions and reduce the risk of infestation.
• Care During Growth: Keeping the soil moist, but not soggy, is essential for onions to thrive. Remove any onions that begin to flower and use them quickly.
• Nutrients and Fertilization: A steady supply of nutrients, such as nitrogen fertilizer, helps promote large, healthy bulbs. Incorporating a layer of compost during planting can improve soil fertility.

By following these guidelines, you will be well prepared to grow onions in your own garden, enjoying the many benefits of a successful homegrown harvest.