Growing Onions: A Comprehensive Guide for UK Gardeners

Introduction

Onions are a staple in kitchens worldwide and one of the easiest crops to grow in the UK. With their versatility in cooking and long storage life, onions are a must-have for any vegetable garden. Whether you’re growing onions from seeds, sets, or transplants, they can be cultivated successfully with a bit of preparation and care.

This guide will take you through everything you need to know about growing onions, from planting and care tips to harvesting and storing them for maximum freshness.

Allotment and Kitchen Garden Book

Are you starting an allotment or planning on growing your own fruit, vegetables, herbs, and flowers in a kitchen garden? If so we highly recommend the book Allotment Month By Month. This does exactly what it does on the cover to help you with what you should be doing in the allotment and kitchen garden each month. Below you can see the link for Amazon where you can purchase the book directly. This book is extremely popular with all allotment holders as you will read in the reviews:-

Click to check the book on Amazon

You can check out all the allotment and kitchen garden books we recommend here.

Why Grow Onions?

1. Easy to Grow

Onions are a low-maintenance crop, making them ideal for beginner gardeners.

2. Cost-Effective

Growing your own onions saves money compared to buying them regularly from stores.

3. Long Storage Life

Onions can be stored for months when properly cured, providing a year-round supply.

4. Versatility

Onions are a kitchen essential, used in a variety of dishes to enhance flavor.

Types of Onions to Grow

1. Bulbing Onions

Examples: Red onions, yellow onions, white onions.
Best For: General cooking, salads, and roasting.

2. Spring Onions (Scallions)

Examples: White Lisbon, Ishikura.
Best For: Raw salads, garnishes, and quick-growing crops.

3. Shallots

Examples: Golden Gourmet, Red Sun.
Best For: Delicate flavor, pickling, and gourmet dishes.

4. Overwintering Onions

Examples: Senshyu Yellow, Radar.
Best For: Autumn planting for early summer harvest.

When to Plant Onions

1. Spring Planting

Timing: March to April.
Best For: Maincrop onions that mature in summer.

2. Autumn Planting

Timing: September to November.
Best For: Overwintering onions that grow through winter and are ready by early summer.

How to Plant Onions

1. Choosing the Right Location

Light: Full sun for best growth.
Soil: Well-draining, fertile soil with a neutral to slightly acidic pH.

2. Preparing the Soil

Remove weeds and loosen the soil.
Add compost or well-rotted manure to enrich the soil.
Avoid freshly manured soil, as it can lead to bulb rot.

3. Planting Methods

Onion Sets:
- Plant sets 1 inch deep, with the pointed end facing up.
- Space sets 4-6 inches apart in rows spaced 12 inches apart.
Onion Seeds:
- Sow seeds thinly in drills 1 inch deep and 6 inches apart.
- Thin seedlings to 4-6 inches apart once they emerge.

Caring for Onions

1. Watering

Water regularly during dry periods, especially when bulbs are forming.
Avoid overwatering, as this can cause rot.

2. Feeding

Apply a high-potash fertilizer every few weeks during the growing season to support bulb development.

3. Weeding

Keep onion beds weed-free, as weeds compete for nutrients and can stunt growth.

4. Mulching

Apply mulch to retain soil moisture and suppress weeds.

Common Problems and Solutions

1. Onion Fly

Symptoms: Yellowing and wilting leaves; maggots in bulbs.
Solution: Use netting to protect crops and rotate planting areas yearly.

2. Downy Mildew

Symptoms: Yellow spots and a greyish mold on leaves.
Solution: Ensure good air circulation, avoid overhead watering, and remove infected plants.

3. Bolting

Symptoms: Premature flowering, which reduces bulb quality.
Solution: Choose bolt-resistant varieties and water consistently to reduce stress.

Harvesting Onions

1. When to Harvest

Harvest onions when the foliage turns yellow and starts to fall over.
Spring-planted onions are ready in late summer, while overwintering onions are ready in early summer.

2. How to Harvest

Use a fork to gently lift the bulbs from the soil.
Leave them to dry on the soil surface for a few days if the weather is dry, or cure them indoors in a well-ventilated space.

Storing Onions

1. Curing

Allow onions to dry for 2-3 weeks until the skins are papery and the necks are completely dry.

2. Storage Tips

Store cured onions in a cool, dry, and well-ventilated space.
Hang them in nets or place them in a single layer on racks to prevent mold.

Companion Planting for Onions

1. Good Companions

Carrots: Repels onion flies.
Lettuce and Beets: Make good use of space in the garden.

2. Avoid Planting With

Legumes (Beans and Peas): Onions can inhibit their growth.

Benefits of Growing Onions

1. Freshness

Homegrown onions are fresher and more flavorful than store-bought ones.

2. Chemical-Free

Growing your own onions ensures they are free from harmful chemicals and pesticides.

3. Sustainability

Reduces reliance on imported onions, lowering your carbon footprint.

4. Versatility

Onions can be used in a wide range of dishes, from soups and stews to salads and sauces.

Common Questions About Growing Onions

1. Can onions grow in containers?
Yes, onions can be grown in pots with well-draining soil and adequate space for root development.

2. How long do onions take to grow?
Onions take 4-5 months to mature, depending on the variety and planting time.

3. Can I plant onions in heavy clay soil?
Amend clay soil with compost and sand to improve drainage before planting.

4. How do I prevent onions from bolting?
Choose bolt-resistant varieties and keep the soil consistently moist to reduce stress.

5. Do onions need full sun?
Yes, onions require full sun for healthy growth and bulb development.

6. How do I know when onions are ready to harvest?
Harvest when the tops turn yellow and fall over.

7. Can I plant onions with other vegetables?
Yes, onions pair well with carrots, lettuce, and beets, but avoid planting with legumes.

8. Do onions require a lot of water?
Onions need consistent moisture, especially during bulb formation, but avoid waterlogging.

9. Can I grow onions from supermarket bulbs?
It’s better to use certified onion sets or seeds to avoid disease and ensure good yields.

10. How do I store onions after harvest?
Cure them for 2-3 weeks, then store in a cool, dry, and well-ventilated space.

Conclusion

Growing onions is a simple and rewarding experience for gardeners of all levels. With proper care and attention, you can enjoy a bountiful harvest of fresh, flavorful onions that enhance your cooking and store well for months. Whether planted in beds, containers, or allotments, onions are a versatile and valuable addition to any garden.

Gardening With Ben Podcasts

If you love podcasts and are passionate about gardening, why not tune in to Gardening with Ben’s Allotment Podcasts? Packed with tips, inspiration, and plenty of down-to-earth advice, Ben’s podcasts are perfect for anyone looking to get the most out of their garden or allotment.

Whether you’re a seasoned gardener or just starting out, Gardening with Ben covers a wide range of topics to keep you informed and motivated. From seasonal planting guides and pest control tips to creating a wildlife-friendly space, there’s something for everyone. Each episode is filled with Ben’s friendly, relatable charm, making it feel like you’re chatting with a gardening buddy.

Don’t miss out on the latest episode below, where Ben shares his insights on what to plant this month, how to prepare your soil, and creative ways to make the most of the colder seasons. It’s the perfect companion for your next cup of tea or a relaxing moment in your gardening shed.

You can also listen to Gardening with Ben’s podcasts on your favorite platforms, including Spotify, Apple Podcasts, and Amazon Music. Prefer hands-free? Simply ask Alexa, “Play Gardening with Ben,” and you’ll be ready to dig into the latest episode.

So, if you’re looking for gardening inspiration, practical advice, or just a bit of friendly encouragement to get your hands dirty, tune in to Gardening with Ben’s Allotment Podcasts. It’s your perfect gardening companion, wherever you are! 🌱🎧