The Ultimate Guide to Growing Autumn Onions in November

Autumn onions are a fantastic crop to grow, particularly for gardeners looking to extend their growing season into the cooler months. Planting onions in November is a great way to ensure an early harvest by late spring or early summer. These hardy vegetables thrive in the cold, making them an ideal choice for autumn and winter gardening. In this guide, we’ll walk you through everything you need to know about planting and growing autumn onions, including tips on preparation, planting, care, and harvesting.

Why Grow Autumn Onions?

Onions are a versatile and essential ingredient in many kitchens, and growing your own can be incredibly rewarding. Autumn onions, also known as overwintering onions or Japanese onions, are varieties that are sown in the fall and harvested the following summer. They are specifically bred to withstand colder temperatures, meaning they can survive frost and even snow, making them perfect for planting in November.

Some benefits of growing autumn onions include:

• Extended growing season: By planting in November, you take advantage of the cooler months when the soil is still workable, and your onions can establish roots before winter.
• Early harvest: Autumn onions are ready for harvest in June or July, giving you a head start on the growing season.
• Low maintenance: Once established, autumn onions require minimal care and can largely be left to grow on their own through the winter.
• Cold-resistant: These onions are bred to thrive in cold weather, ensuring a reliable crop despite harsh conditions.

Choosing the Right Onion Varieties for Autumn Planting

When growing onions in November, it’s essential to select the right variety. Not all onions are suited for cold weather planting, so choosing the appropriate type will ensure a successful harvest. The most popular varieties for autumn planting include:

1. ‘Senshyu Yellow’: A reliable Japanese onion variety that is known for its hardiness. It produces medium-sized bulbs with a mild, sweet flavor.
2. ‘Radar’: Another excellent choice for autumn planting, ‘Radar’ onions are hardy, producing large, golden bulbs with a robust flavor.
3. ‘Electric Red’: This variety produces attractive red onions with a mild taste. It’s slightly less hardy than some yellow varieties, but still performs well in most climates.
4. ‘Troy’: This is a fast-growing variety that is well-suited for colder temperatures, offering a reliable crop of firm, golden onions.

When selecting onion sets or seeds for autumn planting, make sure to choose varieties labeled specifically for overwintering or autumn planting.

Preparing Your Garden for Autumn Onions

Before planting your autumn onions in November, it’s essential to prepare your garden beds to give your crop the best possible start.

Soil Preparation

Onions prefer well-draining, fertile soil with a pH between 6.0 and 7.0. They thrive in loose, sandy loam but can adapt to various soil types as long as it’s not too compacted. To prepare your soil for onions:

1. Clear the bed: Remove any weeds, rocks, or debris from the planting area. Onions don’t compete well with weeds, so starting with a clean bed is crucial.
2. Improve drainage: If your soil is heavy or clay-like, amend it with organic matter such as compost or well-rotted manure. This will help improve drainage and add essential nutrients.
3. Test your soil: Use a soil test kit to check the pH and nutrient levels. Onions prefer a slightly acidic to neutral soil. If your soil is too acidic, add lime to raise the pH.
4. Fertilize: Before planting, incorporate a balanced fertilizer into the soil, such as a 10-10-10 (Nitrogen-Phosphorus-Potassium) fertilizer. This will provide your onions with the nutrients they need to establish strong roots before winter.

Choosing the Planting Location

Onions need full sunlight to thrive, so choose a location in your garden that receives at least six hours of direct sunlight each day. The more sunlight, the larger your onions will grow. Also, consider rotating your crops. Avoid planting onions in the same spot where you’ve grown onions, garlic, or other alliums in the past two years to prevent disease buildup in the soil.

How to Plant Autumn Onions in November

Once your garden bed is prepared, it’s time to plant your autumn onions. You can plant either onion sets (small bulbs) or seeds, but sets are generally more reliable for novice gardeners and will produce faster results.

Planting Onion Sets

1. Spacing: Plant your onion sets about 4 inches apart in rows that are 12 inches apart. This spacing allows for adequate air circulation and room for the bulbs to grow.
2. Planting depth: Push the onion sets into the soil so that the pointed end is facing upwards. The tip of the bulb should be just below the surface of the soil.
3. Firm the soil: Gently press down the soil around each set to ensure good contact between the bulb and the soil. This helps the onions establish roots quickly.

Planting Onion Seeds

If you prefer to grow onions from seed, follow these steps:

1. Sow seeds: Sow onion seeds about 1/4 inch deep in rows spaced 12 inches apart. Thin the seedlings once they emerge to maintain a spacing of about 4 inches between each plant.
2. Cover the seeds: Lightly cover the seeds with soil and water gently. Keep the soil moist until the seeds germinate, which can take up to 10 days.
3. Protect from birds: Birds are known to peck at freshly planted onions, especially when the shoots first appear. Use netting or row covers to protect your onions from birds.

Caring for Autumn Onions Through Winter

Once planted, autumn onions require minimal care, but a few key steps will ensure a healthy crop.

Watering

While onions don’t require much water during the winter months, it’s essential to keep the soil slightly moist as the bulbs establish roots. Once the cold sets in, natural rainfall should provide enough moisture, but check the soil occasionally to ensure it doesn’t dry out completely. Avoid overwatering, as soggy soil can lead to rot.

Mulching

Adding a layer of mulch, such as straw or compost, around your onions will help regulate soil temperature, retain moisture, and suppress weeds. Mulching also provides extra protection against harsh winter conditions.

Weed Control

Weeds compete with onions for nutrients and water, so keep your onion bed weed-free. Carefully remove any weeds that appear, making sure not to disturb the onion bulbs.

Pest and Disease Management

Autumn onions are generally hardy and resistant to pests, but it’s still essential to monitor your crop. Common onion pests include:

• Onion fly: These flies lay eggs near the base of the plant, and the larvae burrow into the bulbs. Use row covers or fine netting to prevent this pest from reaching your onions.
• Slugs and snails: These pests can nibble on the shoots. Handpick slugs or set up slug traps to keep them away.

In terms of diseases, onions can be susceptible to fungal infections such as downy mildew or white rot. To prevent these diseases, avoid overwatering, ensure proper air circulation, and rotate crops each year.

Harvesting Your Autumn Onions

After a long winter, your onions will be ready for harvest by June or July. You’ll know they’re ready when the green tops begin to yellow and flop over. At this point, the bulbs have reached full size, and you can start lifting them out of the ground.

1. Harvesting: Gently lift the onions from the soil using a garden fork or spade, taking care not to damage the bulbs.
2. Curing: Once harvested, allow the onions to cure in a warm, dry, and well-ventilated area for a couple of weeks. This process helps toughen the skins and prepares them for storage.
3. Storing: After curing, trim the tops and roots, and store your onions in a cool, dry place. Properly cured onions can last for several months, providing you with a homegrown supply of onions well into the fall.

Common Problems When Growing Autumn Onions

While autumn onions are generally easy to grow, you may encounter a few common issues:

• Bolting: Onions can bolt (flower prematurely) if they experience fluctuating temperatures or stress. To reduce the risk, make sure you plant at the right time and avoid disturbing the plants.
• Small bulbs: If your onions produce small bulbs, it could be due to overcrowding, lack of sunlight, or insufficient nutrients. Ensure proper spacing, adequate sun exposure, and regular feeding for optimal growth.
• Rot: Overwatering or poor drainage can lead to bulb rot. Always check your soil’s moisture levels and ensure good drainage.

Conclusion

Growing autumn onions in November is a rewarding and straightforward way to enjoy an early harvest of one of the kitchen’s most essential ingredients. By choosing the right varieties, preparing your soil correctly, and providing basic care through the winter, you can ensure a healthy crop come June or July. With the tips in this guide, you’ll be well on your way to growing delicious, homegrown onions that will enhance your garden and your meals.

So grab your onion sets, prepare your beds, and get planting—your garden will thank you in the spring!

Check out lots more to grow in November here