Best Onion Varieties to Grow in the UK – Complete Guide

Choosing the best onion varieties to grow in the UK can make a huge difference to your harvest. Whether you want hardy overwintering onions, reliable spring onion sets, colourful red onions, impressive giant bulbs or onions that will store through winter, there’s a variety to suit almost every gardener.

Onions are one of the vegetables I think every allotment gardener should consider growing.

They’re used in so many everyday meals, don’t require huge amounts of growing space and can provide a really useful harvest from a relatively small vegetable bed.

But when you look through a garden centre or seed catalogue, you’ll quickly discover that there’s much more to onion growing than simply buying a bag of sets.

You’ve got yellow onions, red onions and white onions.

There are varieties specially suited to autumn planting, others intended for spring, and some that are particularly good for growing from seed.

Then you’ve got onions selected for producing enormous bulbs and varieties known for keeping well in storage.

Here at Gardening with Ben, I always think choosing the correct variety is one of the most important steps in growing a successful crop.

An onion that performs beautifully when planted in September might not be the right choice for ordinary spring planting.

Likewise, an onion grown specifically for its size might not be the best variety if you want bulbs that can be stored for several months.

And if you’ve got heavy clay soil or an exposed allotment in northern England, the growing conditions need consideration too.

In this complete guide, I’ll explain the best onion varieties for UK gardens and allotments.

We’ll look at autumn onions, spring onion sets, red and white varieties, large onions, storage onions and some excellent choices for beginners.

I’ll also explain when to plant them, what makes each variety worth growing and how to choose a mixture that can keep your kitchen supplied with homegrown onions.

So let’s find the right onion varieties for your garden!

What Makes a Good Onion Variety for UK Gardens?

Before choosing which onions to grow, it’s worth thinking about what you actually want from the harvest.

Some gardeners want onions as early as possible.

Others are more interested in producing a large maincrop that can be stored and used during autumn and winter.

You might prefer red onions because you use them in salads and homemade chutney.

Or perhaps you’d love the challenge of growing an enormous exhibition onion.

The most important things to consider are planting season, reliability, storage life, bulb size, flavour and resistance to bolting.

Autumn or Spring Planting?

Autumn varieties are selected to grow through winter.

Spring varieties are normally planted after the coldest weather has passed.

Storage or Fresh Eating?

Some varieties are particularly suitable for long-term storage.

Others are best enjoyed relatively soon after harvesting.

Red, Yellow or White?

Colour affects appearance and often flavour, although individual varieties can differ considerably.

Sets or Seeds?

Some varieties are widely available as sets, while others are primarily sold as seed.

Is Bolting Resistance Important?

Yes, particularly when growing onions from sets.

Bolting means the plant produces a flower stem, which can affect bulb quality and storage.

Gardening with Ben tip: Rather than buying one variety every year, try growing a small selection and see which performs best in your own allotment soil.

1. Sturon – Best All-Round Yellow Onion

Sturon is one of the most useful onions to consider for a UK allotment.

It’s a traditional yellow-skinned variety with good flavour and excellent storage qualities.

The Royal Horticultural Society lists Sturon among its recommended onion varieties and recognises it as a reliable crop.

When Should You Plant Sturon?

Spring is the normal planting season for sets.

March and April are particularly suitable months when the soil is workable.

Sturon can also be grown from seed.

What Does It Look Like?

It produces attractive golden-brown bulbs with pale flesh.

What Is It Best Used For?

Sturon is an excellent everyday cooking onion.

It’s useful for soups, casseroles, curries, sauces and homemade onion gravy.

Does It Store Well?

Yes, with correct curing and suitable storage conditions.

Who Should Grow It?

I’d recommend Sturon to beginners and experienced gardeners who want a dependable maincrop onion.

If I were choosing just one traditional yellow onion for storage, Sturon would be near the top of my list.

2. Centurion – Best for Earlier Spring Harvesting

Centurion is another excellent variety.

It’s a yellow onion known for producing good-quality bulbs and cropping relatively early.

The RHS recognises Centurion for its bronze-brown skin, pale flesh and useful storage qualities.

When Should You Plant Centurion?

Plant suitable sets during spring.

Is Centurion Earlier Than Sturon?

Centurion is generally recognised as an early-cropping variety, although harvest dates depend on conditions.

What Are the Bulbs Like?

They have attractive brown skins and pale flesh.

Can You Store Them?

Yes.

Is Centurion Good for Beginners?

Absolutely.

It’s a useful choice if you want a reliable yellow onion that can be grown using the straightforward set-planting method.

What Would I Use It For?

Everything from soups and roasted vegetables to homemade chutney and cooking sauces.

3. Red Baron – Best Red Onion for General Growing

If you want red onions, Red Baron is a fantastic variety to consider.

It produces attractive dark red bulbs with a strong flavour.

The RHS recommends Red Baron and notes that it crops during mid to late summer and stores well.

When Should You Plant Red Baron?

It’s commonly grown from spring-planted sets or seed.

Can You Grow It from Seed?

Yes.

What Does It Taste Like?

Red Baron has a relatively strong flavour compared with some mild salad varieties.

What Is It Best Used For?

It’s particularly useful for roasting, salads, sandwiches, pickled red onions and homemade red onion chutney.

Does It Store Well?

Yes, when mature bulbs are properly cured and kept in good conditions.

Is It Worth Growing?

Definitely.

I’d recommend growing at least one red onion variety alongside your yellow onions.

It gives you more colour and flexibility in the kitchen.

4. Hercules – Best for Growing Larger Onions from Sets

Hercules is worth considering if you want good-sized onions.

It’s recognised by the RHS for producing large bulbs with a strong flavour and good resistance to bolting.

When Should You Plant Hercules?

It’s commonly sold as a spring-planting variety.

Will It Produce Giant Onions?

It can produce large bulbs, but growing enormous exhibition onions is a separate challenge.

Is Spacing Important?

Absolutely.

Allow enough room for the bulbs to develop.

Can You Overfeed It?

Yes.

Excessive nitrogen isn’t a guarantee of bigger onions and can affect crop maturity.

What Is It Best Used For?

General cooking where you want large, useful bulbs.

Who Should Grow It?

Gardeners who want a larger onion without necessarily entering an exhibition competition.

5. Rumba – Best Reliable General-Purpose Onion

Rumba is another variety worth having on your shortlist.

The RHS recommends it for producing medium-sized yellow onions that grow and store well.

Is It Good for UK Weather?

It’s suitable for normal UK growing conditions when planted appropriately.

When Should You Plant It?

Generally during the spring planting period.

What Size Are the Bulbs?

Usually medium-sized.

What Can You Use It For?

Rumba is a practical kitchen onion for soups, stews, casseroles and sauces.

Does It Store Well?

Yes, one of its useful characteristics is storage quality.

Why Would I Choose It?

If you want a dependable all-rounder rather than the biggest bulb or an unusual colour, Rumba is well worth trying.

6. Stuttgarter – Best Traditional Beginner Variety

Stuttgarter, sometimes sold as Stuttgarter Giant, is a familiar yellow onion often grown from sets.

It’s known for relatively flattened bulbs and a mild flavour.

The RHS school gardening guidance includes it among suitable spring-planted varieties.

When Should You Plant It?

During spring.

Is It Easy to Grow?

It’s widely considered a good choice for beginners.

What Shape Are the Bulbs?

They tend to be flatter than some rounded onion varieties.

Does It Store Well?

It has useful keeping qualities when properly cured.

What Is It Good For?

General everyday cooking.

If you’re starting out with onion sets, Stuttgarter is another variety to compare with Sturon.

7. Radar – Best Hardy Autumn Onion

Radar is one of the best-known overwintering onion varieties in the UK.

It’s normally sold as autumn onion sets.

The RHS school gardening guidance identifies Radar as a yellow onion with good resistance to bolting.

When Should You Plant Radar?

September and October are the main planting months.

Can You Plant It in November?

In suitable well-drained conditions, late planting may be possible, but earlier establishment is preferable.

Can It Survive Winter?

Radar is selected for overwintering, although severe conditions and waterlogging can still cause losses.

When Will It Harvest?

Often June or July.

What Is It Best Used For?

Fresh early-season cooking.

Is Radar a Good Choice for Northern England?

It can be, provided you have a reasonably sheltered, well-drained growing area.

For a Yorkshire allotment, I’d pay particular attention to drainage before planting any autumn onions.

8. Senshyu Yellow – Best Traditional Japanese Overwintering Onion

Senshyu Yellow is another popular overwintering variety.

It’s frequently described as a Japanese onion and is grown for an earlier harvest the following year.

The bulbs have yellow skins and a relatively mild, sweet flavour.

When Should You Plant Senshyu Yellow?

During autumn, generally September or October.

Is It Suitable for Beginners?

Yes, if the soil conditions are suitable.

Can You Harvest It Young?

Yes.

Some young plants can be harvested early for fresh use, although doing so reduces the number of mature bulbs.

When Will Mature Bulbs Be Ready?

Usually June or July.

Does It Store for Months?

Storage life varies, but many overwintering onions are best used sooner than established maincrop storage varieties.

Why Grow It?

It’s a useful choice if you’re trying to extend the homegrown onion harvesting season.

9. Electric – Best Autumn Red Onion

Electric is a red onion variety commonly sold for autumn planting.

It produces attractive red-skinned bulbs and is particularly useful if you enjoy colourful onions in the kitchen.

When Should You Plant Electric?

Usually September or October.

Is It Suitable for Overwintering?

Yes, when grown in appropriate conditions.

When Will It Harvest?

Normally early summer.

What Is It Best Used For?

Salads, roasting, fresh cooking and pickling.

Should You Grow It Instead of Red Baron?

Not necessarily.

Electric is a useful autumn red onion, while Red Baron is a well-known spring-growing variety.

Growing both can spread your red onion harvest.

What Would I Recommend?

Try a short autumn row of Electric and a spring row of Red Baron.

That would provide an interesting comparison.

10. Marshalls Red Fen – Another Excellent Autumn Red Onion

Marshalls Red Fen is a red onion recognised by the RHS.

It’s notable because suitable sets can be planted in autumn, and the bulbs have good flavour and storage qualities.

What Makes It Different?

It’s another option for gardeners who want overwintering red onions.

Does It Store Well?

The RHS specifically identifies useful storage qualities.

Is It Better Than Electric?

Not necessarily.

Both are worth comparing, and local growing conditions can influence the results.

When Should You Plant It?

Use its recommended autumn planting window.

What Is It Best Used For?

Everyday red onion recipes, including roasting, chutney and cooking.

11. Shakespeare – Another Autumn Yellow Onion to Consider

Shakespeare is another variety sold as overwintering onion sets.

It produces brownish-yellow bulbs and is grown for harvesting the following summer.

When Should You Plant Shakespeare?

During autumn, following the packet instructions.

What Is Its Main Advantage?

It’s another opportunity to grow onions through winter.

Can It Be Used for Storage?

Suppliers describe useful keeping qualities, but actual storage depends on maturity, curing and conditions.

Is It Suitable for Wet Clay?

Not if the ground remains waterlogged.

Should You Try It?

Yes, especially if you want to compare several overwintering varieties.

Growing a small trial row can help you discover what works best on your allotment.

12. Ailsa Craig – Best for Large Mild Onions

Ailsa Craig is a traditional onion variety well known among growers interested in larger bulbs.

The RHS lists Ailsa Craig among varieties suitable for exhibition onions weighing over 250 g.

Is It Grown from Seed?

Usually, yes.

When Should You Sow It?

Start indoors during winter or early spring according to the seed packet.

Is It Suitable for Beginners?

It’s possible, but producing very large bulbs requires careful growing conditions.

What Is the Flavour Like?

Ailsa Craig is generally known as a comparatively mild onion.

Does It Store Well?

It’s usually grown for size and fresh use rather than being chosen as the longest-keeping storage onion.

What Is It Best For?

Large slicing onions, cooking and growing competitions.

13. The Kelsae – Best for Giant Exhibition Onions

If you’ve ever wanted to grow an enormous onion, The Kelsae is a variety worth investigating.

The RHS lists The Kelsae among recommended large exhibition onion varieties.

However, giant onions require more care than a straightforward crop grown from sets.

Should You Start from Seed?

Yes.

When Should You Sow?

Early indoor sowing is common, following specialist seed-growing instructions.

Does It Need Good Light?

Absolutely.

Starting early without enough light can produce weak seedlings.

Will Every Onion Become Enormous?

No.

Large bulb potential depends on variety, growing season, soil, spacing and care.

Does It Store Well?

Giant exhibition types aren’t generally the first choice for long-term kitchen storage.

Would I Recommend It?

If you enjoy growing challenges, definitely try a few plants alongside your ordinary maincrop onions.

Which Are the Best Onion Varieties for Autumn Planting?

If you’re looking specifically for autumn onions, my suggested shortlist would be:

• Radar for yellow overwintering onions.
• Senshyu Yellow for an early, mild-flavoured crop.
• Electric for red onions.
• Marshalls Red Fen for another red option.
• Shakespeare for an alternative yellow overwintering variety.

The most important thing is buying sets specifically intended for autumn planting.

Planting normal spring onion sets in September isn’t the same as choosing a suitable overwintering cultivar.

For most UK gardeners, September and October are the main planting months.

If your soil becomes extremely wet during winter, consider raised beds or establishing sets in modules.

Which Are the Best Onion Varieties for Spring Planting?

For spring onion sets, I’d focus on varieties such as Sturon, Centurion, Red Baron, Hercules, Rumba and Stuttgarter.

These give you a useful choice of colours, bulb sizes and storage qualities.

Spring onion sets are normally planted during March and April when the soil is suitable.

If you’re a beginner, Sturon and Centurion are particularly straightforward options.

For red onions, Red Baron is an excellent addition.

And if you’d like to grow larger bulbs, Hercules is worth trying.

Best Onion Varieties for Winter Storage

If you want homegrown onions that will keep well beyond the summer harvest, variety choice matters.

Sturon, Centurion, Red Baron and Rumba are all recognised by the RHS as having good storage qualities.

However, choosing a suitable variety is only part of the process.

You also need to allow the bulbs to mature properly.

Wait for the foliage to yellow and fall naturally.

Lift the onions carefully without bruising them.

Then dry and cure the bulbs until the outer skins are papery and the necks are thoroughly dry.

Store healthy bulbs in a cool, dry, ventilated location.

Check them regularly for signs of decay.

Don’t expect damaged bulbs to keep as well as healthy ones.

Best Onion Varieties for Heavy Clay Soil

This is an important consideration for allotment gardeners in northern England.

Onions can grow in fertile clay soil, but they don’t like prolonged waterlogging.

The variety alone won’t solve drainage problems.

If your soil remains saturated through winter, autumn sets may struggle regardless of how hardy they’re described as being.

What Would I Grow?

In difficult winter soil, I’d prioritise reliable spring varieties such as Sturon, Centurion or Red Baron.

Spring planting allows you to wait until the worst winter wet has passed.

Can Raised Beds Help?

Yes, where they improve drainage.

Can You Start Sets in Modules?

Absolutely.

Are Autumn Onions Impossible on Clay?

No.

If your clay soil drains adequately, suitable overwintering varieties can still do well.

What’s My Recommendation?

Assess the soil first, then choose the variety and planting season.

Best Onion Varieties for Growing in Pots

You can grow many ordinary bulb onion varieties in sufficiently large containers.

The RHS recommends pots at least 45 cm wide and deep.

Choose a sunny position and ensure the container drains properly.

For a straightforward container crop, I’d consider Sturon, Red Baron or another reliable standard bulb onion.

Avoid overcrowding the pot.

Although onions don’t have extremely deep roots, they still need space and nutrients to develop useful bulbs.

Check moisture regularly because containers can dry out faster in warm weather.

And if you’re growing on a patio, remember that very large exhibition onions need more space and attention than ordinary kitchen onions.

How to Choose Between Red, Yellow and White Onions

Yellow onions are incredibly versatile.

They’re suitable for soups, casseroles, roasting, onion gravy and many other cooked dishes.

Red onions are particularly attractive in salads, sandwiches and chutneys.

They also roast beautifully.

White onions offer another choice of appearance and flavour, although the characteristics vary between cultivars.

Don’t assume every red onion is mild or every yellow onion is strong.

The individual variety makes a difference.

My advice would be to grow a combination of colours if you have enough space.

That way, you’ll have more options in the kitchen.

Growing Onion Varieties from Seeds or Sets

Another decision is whether to start with onion sets or seeds.

Sets are usually easiest for beginners.

They’re small immature bulbs that you plant directly into the ground.

Seeds require more early care, particularly when started indoors during January or February.

However, seeds usually provide a wider choice of varieties.

They’re also useful if you want to try specialist or exhibition onions.

Are Sets Better for a Maincrop?

They’re certainly convenient.

Are Seeds Better for Giant Onions?

Specialist large-bulb varieties are often grown from seed.

Can Both Produce Good Onions?

Absolutely.

What Would I Recommend?

Grow your maincrop from reliable sets if you want a simple method.

Then experiment with a few varieties from seed.

When to Harvest Different Onion Varieties

Harvesting dates depend on planting season, variety and weather.

Autumn-planted onions are generally ready during June or July.

Spring-planted sets and seed-grown maincrop onions usually mature between July and early autumn.

Don’t rely entirely on the calendar.

Instead, look at the plants.

As onions approach maturity, their leaves begin yellowing and falling naturally.

The bulbs should be well developed and have their characteristic mature appearance.

Carefully lift them and allow suitable storage varieties to cure.

Avoid bending onion leaves over artificially because this isn’t recommended by the RHS.

Ten Common Mistakes When Choosing Onion Varieties

1. Buying Spring Sets for Autumn Planting

Always check the intended planting season.

2. Choosing Only One Variety

Growing several varieties can extend harvests and provide different uses.

3. Expecting Every Onion to Store Well

Storage qualities vary considerably.

4. Buying Giant Onion Seed for Easy Storage

Large exhibition onions aren’t always the best storage choice.

5. Ignoring Bolting Resistance

Choose varieties suited to your conditions.

6. Planting Autumn Sets into Waterlogged Ground

Even hardy onions can rot in saturated soil.

7. Choosing Varieties Unsuitable for UK Day Length

Select cultivars recommended for UK growing conditions.

8. Overcrowding Large-Bulb Varieties

Give plants enough room.

9. Forgetting About Kitchen Use

Grow varieties you’ll actually enjoy eating.

10. Assuming the Same Variety Performs Identically Everywhere

Soil, rainfall, temperature and growing methods all affect results.

Frequently Asked Questions About Onion Varieties

What is the best onion variety to grow in the UK?

Sturon is an excellent all-round choice, but the best variety depends on planting season and intended use.

What is the best onion for beginners?

Sturon, Centurion and Stuttgarter are useful spring-set choices.

What is the best autumn onion variety?

Radar and Senshyu Yellow are well-known overwintering options.

What is the best spring onion-set variety for full-sized bulbs?

Sturon or Centurion are good choices.

Which red onion is best to grow?

Red Baron is a reliable spring-growing option, while Electric is suitable for autumn planting.

What onion stores the longest?

Storage depends on conditions, but Sturon, Centurion, Red Baron and Rumba are known for good keeping qualities.

Which onion variety produces the biggest bulbs?

Ailsa Craig and The Kelsae are recognised large-bulb exhibition varieties.

Are Radar onions good for winter?

Yes, they’re specifically grown as overwintering onions.

Are Senshyu Yellow onions suitable for autumn?

Yes.

Can you plant Red Baron in October?

Red Baron is generally treated as a spring-growing variety. Choose a red onion specifically sold for overwintering, such as Electric or Marshalls Red Fen, for autumn planting.

Does Electric produce red onions?

Yes.

Can you grow Sturon from seed?

Yes.

Does Hercules produce large onions?

Yes, it’s known for relatively large bulbs.

Are yellow onions easier to grow than red onions?

Not necessarily. Variety choice and growing conditions matter more than skin colour alone.

Can onions grow in clay soil?

Yes, provided drainage is adequate.

Which onions are best for a Yorkshire allotment?

Reliable spring varieties such as Sturon, Centurion and Red Baron are sensible starting points. Hardy autumn varieties can also grow well in suitable drainage conditions.

Are autumn onions harvested earlier?

Usually, yes.

Can you grow onions in raised beds?

Yes.

Can you grow onions in pots?

Yes, in sufficiently large containers.

Is it worth growing several onion varieties?

Absolutely. Different varieties provide different harvest times, colours, flavours and storage qualities.

Final Thoughts: My Favourite Onion Varieties to Recommend

So, which onion varieties should you grow in the UK?

For me, it makes sense to grow a mixture rather than relying on one type.

If you want a reliable yellow onion for everyday cooking and storage, Sturon is an excellent place to start.

Centurion is another useful choice, especially if you want a relatively early-cropping spring onion.

For red onions, Red Baron is hard to overlook.

It produces attractive bulbs that are fantastic in salads, roasting dishes and homemade chutney.

If you’re planning an autumn crop, Radar and Senshyu Yellow are two of the best-known options.

And if you enjoy red onions, Electric is worth adding to your overwintering collection.

For gardeners interested in growing larger bulbs, Hercules is a useful choice from sets.

And if you’re looking for a challenge, why not try growing Ailsa Craig or The Kelsae from seed?

One of the things I love about allotment gardening is experimenting.

You might discover that one variety performs particularly well in your soil while another struggles.

And you won’t necessarily know until you’ve tried it.

If you’ve got enough room, grow a short row of two or three different onions.

Record the planting dates.

Compare how they grow.

Look at the size of the harvest.

And see which varieties keep best after drying.

Over time, you’ll discover which onions are most reliable for your own allotment.

But whatever you choose, remember that healthy soil, suitable planting dates, correct spacing and regular care are just as important as the variety itself.

And when harvest time arrives, you’ll have all those lovely onions ready for the kitchen.

Perfect for French onion soup, homemade onion gravy, red onion chutney, roasted onions and plenty of other fantastic recipes.

Keep smiling, keep shining, keep gardening with Ben!