How to Grow Garlic and Onions Together – Complete UK Guide

Growing garlic and onions together is a fantastic way to make use of your vegetable beds during autumn and winter, and both crops can produce excellent harvests when planted correctly.

But can you really plant garlic and onions in the same raised bed?

Will they grow well together, or will one crop compete with the other?

And what about feeding, watering, spacing and the pests and diseases that affect both vegetables?

These are questions worth asking before you start planting.

Here at Gardening with Ben, I enjoy growing garlic, elephant garlic, onions and shallots on the allotment.

They’re some of my favourite crops to plant during autumn because they allow me to get the following year’s harvest underway while many of the summer vegetables are coming to an end.

And one of the things I particularly like about growing onions and garlic is how manageable they are.

You don’t need enormous growing beds or complicated equipment.

You simply need healthy planting material, suitable soil and enough room for each bulb to develop.

Garlic and onions also have similar growing requirements.

Both prefer sunny positions, fertile soil and good drainage.

This makes them suitable for growing alongside each other in an allotment bed or raised bed.

However, there’s something important to remember.

Garlic and onions belong to the same plant family, which means they can suffer from many of the same pests and diseases.

Growing them together can be convenient, but it doesn’t mean they’ll automatically protect one another.

In this complete UK guide, I’ll explain exactly how to grow garlic and onions together, including when to plant them, how deep each crop should go and how far apart they need to be.

We’ll also look at autumn versus spring planting, watering, feeding, raised beds, crop rotation and harvesting.

Whether you’re growing these vegetables for the first time or planning your autumn allotment jobs, this guide will help you make the most of your growing space.

Can You Grow Garlic and Onions Together?

Yes!

Garlic and onions can grow successfully in the same vegetable bed.

They’re closely related crops with broadly similar growing requirements.

Both generally prefer:

• Full sun.
• Fertile soil.
• Good drainage.
• A relatively weed-free growing area.
• Adequate moisture during active growth.
• Balanced nutrition.
• Sufficient spacing for bulbs to develop.

This means you don’t need entirely different growing conditions for each crop.

However, you should still treat them as two individual vegetables with their own planting requirements.

Is It Better to Mix Them or Grow Them in Separate Rows?

Both approaches can work.

You could alternate blocks of garlic and onions within one raised bed.

Alternatively, you could grow garlic in one half and onions in the other.

For most gardeners, I would recommend clearly labelled rows or blocks.

This makes it easier to remember which varieties you’ve planted and to harvest them at the appropriate time.

Will Garlic Stop Onion Pests?

Not reliably.

Some companion-planting advice suggests that strong-smelling alliums deter certain pests.

However, garlic and onions share several pests, so planting them together isn’t a proven method for protecting either crop.

Are There Any Disadvantages?

Yes.

If serious allium pests or diseases develop, both crops may be affected.

That’s why healthy planting stock, good hygiene and appropriate crop rotation are particularly important.

Why Garlic and Onions Make Good Growing Neighbours

Although they don’t provide guaranteed pest protection, garlic and onions can be convenient crops to grow alongside one another.

1. They Prefer Similar Soil

Both grow best in fertile, well-drained soil.

You don’t need one crop in wet soil and the other in dry soil.

2. Both Need Plenty of Sunlight

A sunny vegetable bed can provide suitable growing conditions for both.

3. They Suit Organised Planting

Garlic cloves and onion sets can be positioned in neat, evenly spaced rows.

4. They Can Both Be Planted in Autumn

Suitable autumn onion sets and many garlic varieties can be planted during the same season.

5. They Are Relatively Easy to Maintain

Once established, both crops need regular checks rather than constant attention.

6. They Can Be Grown in Raised Beds

Raised beds can be especially helpful where winter drainage is a concern.

7. They Can Provide Summer Harvests

Many autumn-planted onions and garlic varieties are harvested during summer.

However, their actual harvest dates can differ.

Gardening with Ben tip: If you’re growing onions and garlic together, keep them in labelled rows rather than mixing everything randomly. It makes looking after the crops and harvesting them much easier.

Are Garlic and Onions Companion Plants?

Garlic and onions are sometimes described as companion plants.

However, it’s useful to understand what companion planting actually means.

Companion planting involves growing different plants near one another in the hope of gaining benefits such as pest deterrence, improved use of space or better growing conditions.

Some combinations have useful supporting evidence.

Others are mainly based on gardening tradition.

Do Garlic and Onions Help Each Other Grow?

There isn’t strong evidence that garlic increases the growth of onions, or that onions automatically improve garlic yields, simply because they’re planted together.

They have compatible growing requirements, which is useful.

But compatibility isn’t the same as a special companion-planting benefit.

Does Garlic Repel Onion Fly?

Don’t rely on it.

Onion fly can attack onions and other alliums, including garlic.

Does Growing Garlic with Onions Prevent White Rot?

No.

Onion white rot can affect both crops.

Should You Avoid Growing Them Together?

Not necessarily.

If your soil is healthy, you’ve bought suitable planting material and you can manage both crops properly, growing them in the same bed can be perfectly reasonable.

The important thing is understanding the shared risks.

When Should You Plant Garlic and Onions Together in the UK?

October is an excellent month to plant suitable autumn garlic and overwintering onion sets together.

However, not every garlic variety or onion variety is intended for autumn planting.

Always check the instructions supplied with your planting material.

Planting in September

Some overwintering onion sets can be planted from September.

Certain garlic varieties may also have an early autumn planting window.

However, October is more typical for many garlic varieties.

Planting in October

October is a particularly good month.

Many autumn garlic varieties can be planted, while suitable overwintering onions can also be established.

Planting in November

November can still be suitable for both crops, depending on the varieties and soil conditions.

Avoid planting into saturated or frozen ground.

Can You Plant Both in December?

Some garlic varieties can be planted during December.

However, autumn onion-set planting is usually best completed earlier, according to the variety’s instructions.

Don’t assume that the same planting window applies to both crops.

What About Spring?

Ordinary spring onion sets are commonly planted during early to mid-spring.

Some garlic varieties are also suitable for late-winter or early-spring planting.

You can therefore grow spring-planted onions and suitable garlic together, but their planting times may not be identical.

Autumn Onion Sets vs Spring Onion Sets

This distinction is particularly important.

Onions sold as sets are small immature bulbs intended for planting.

There are two main seasonal groups sold to UK gardeners.

Autumn Onion Sets

These are selected for overwintering.

They can generally be planted during early or mid-autumn, depending on the variety.

They establish before winter and continue growing as conditions improve.

Spring Onion Sets

These are usually planted during spring.

They grow during the warmer months and are harvested later in the year.

Can You Plant Spring Onion Sets in October?

It’s not recommended unless the supplier specifically says the variety is suitable for autumn planting.

Varieties differ in cold tolerance and their likelihood of bolting.

Which Are Better to Grow with Autumn Garlic?

Choose varieties sold specifically as overwintering or autumn onion sets.

What Are the Best Onions to Grow with Garlic?

The best varieties are those suited to your planting date and growing conditions.

When choosing autumn onions, look for named overwintering varieties from reputable suppliers.

Examples commonly sold for autumn planting include:

‘Senshyu Yellow’

A traditional overwintering onion variety.

It’s often chosen for autumn planting and an early summer harvest.

‘Radar’

A popular autumn onion-set variety grown by many UK gardeners.

‘Electric’

A red onion variety that is commonly offered as autumn planting sets.

‘Shakespeare’

Another overwintering onion-set variety worth considering.

Does the Variety Really Matter?

Yes.

Not every onion variety responds to winter conditions in the same way.

Some are more likely to bolt after exposure to certain temperature conditions.

Buy autumn onion sets for autumn planting and follow the supplier’s recommended dates.

What Garlic Varieties Can You Plant with Onions?

Several named garlic varieties are suitable for UK cultivation.

Examples include:

‘Solent Wight’

A softneck garlic valued for its storage qualities.

‘Germidour’

A popular softneck garlic that can produce attractive bulbs.

‘Cristo’

A softneck garlic commonly offered by UK gardening suppliers.

‘Arno’

A softneck variety known for its keeping qualities.

What About Hardneck Garlic?

Hardneck garlic can also be grown alongside onions.

However, some varieties produce flowering stems called scapes.

These may require additional attention if bulb size is your priority.

Can You Grow Elephant Garlic with Onions?

Yes, but elephant garlic requires considerably more space than ordinary garlic.

Allow around 25–30 cm between elephant garlic plants as a starting point and keep enough distance from surrounding onions.

What Soil Do Garlic and Onions Prefer?

Both crops perform best in fertile, well-drained soil.

This is particularly important for autumn planting because the plants will remain outdoors during wet British winter weather.

Do They Like Clay Soil?

They can grow in clay soil if drainage is adequate.

However, heavy soil that remains waterlogged for prolonged periods can cause bulbs to rot.

Do Garlic and Onions Need Rich Soil?

Both benefit from sufficient nutrients.

However, the soil doesn’t need to be overloaded with fertiliser.

Can You Use Homemade Compost?

Yes.

Mature garden compost can improve soil structure and moisture retention.

Should You Add Fresh Manure?

Avoid adding fresh manure immediately before planting bulbs and cloves.

Use suitable, well-rotted organic matter instead.

Do They Like Full Sun?

Yes.

Choose a position that receives plenty of sunlight.

Too much shade may reduce bulb development.

How to Prepare a Bed for Growing Garlic and Onions Together

Before planting, spend a little time preparing the growing area.

Step 1: Remove Previous Crops

Clear away finished summer vegetables and unwanted plant material.

Step 2: Remove Persistent Weeds

Pay particular attention to bindweed, couch grass and other established weeds.

Step 3: Check the Soil

Avoid planting into heavily compacted or saturated ground.

Step 4: Improve Soil Structure

Add mature compost if the soil requires improvement.

Step 5: Check Drainage

After rainfall, water should be able to drain away.

Step 6: Rake the Surface

Produce a reasonably even planting area.

Step 7: Mark the Rows

Plan which rows will contain garlic and which will contain onions.

Step 8: Leave Room for Harvesting

Remember that you may harvest the two crops at different times.

Organised rows make this much easier.

How to Grow Garlic and Onions Together – Step-by-Step

Here’s a straightforward method for planting autumn garlic and overwintering onion sets into the same UK vegetable bed.

Step 1: Choose the Right Planting Material

Buy healthy garlic intended for planting.

Choose onion sets specifically recommended for autumn planting.

Step 2: Prepare the Soil

Use a sunny, fertile and well-drained growing area.

Step 3: Decide on Your Layout

You could plant two rows of garlic followed by two rows of onions.

Alternatively, divide the bed into two separate blocks.

Step 4: Separate the Garlic Bulbs

Break the garlic bulbs into individual cloves.

Keep the protective skins around the cloves intact where possible.

Step 5: Mark the Garlic Positions

Aim for approximately 15 cm between ordinary garlic cloves.

Allow sufficient space between rows.

Step 6: Plant the Garlic Cloves

Place each clove with its pointed end upwards.

The flat basal plate should face downwards.

Step 7: Cover the Garlic Correctly

Position the tip of each clove approximately 2.5 cm below the soil surface, unless the variety’s instructions say otherwise.

Step 8: Mark the Onion Rows

For onion sets, aim for approximately 10–15 cm between sets.

Wider spacing is useful if you want larger bulbs.

Step 9: Plant the Onion Sets

Push each set gently into prepared soil.

Position the pointed end upwards.

Step 10: Leave the Onion Tips Showing

Unlike ordinary garlic cloves, onion sets are commonly planted with their pointed tips just visible above the soil surface.

Step 11: Firm the Soil

Gently firm around the onions and garlic.

Avoid compacting the bed excessively.

Step 12: Water if Necessary

If the soil is dry, water gently.

If the ground is already moist, extra watering may not be required.

Step 13: Label Both Crops

Include the variety names and planting dates.

Step 14: Protect Against Birds

Birds sometimes pull newly planted onion sets from the soil.

Temporary horticultural fleece or securely installed wildlife-safe protection can help until roots establish.

Step 15: Monitor Growth

Keep the bed free from weeds and inspect drainage throughout winter.

How Deep Do You Plant Garlic and Onion Sets?

Although both are alliums, they aren’t planted at exactly the same depth.

Crop	General planting depth
Ordinary garlic	Pointed tip approximately 2.5 cm below the soil surface
Autumn onion sets	Pointed tip just visible above the soil surface
Elephant garlic	Follow supplier instructions; generally deeper overall than ordinary onion sets

Why Are the Depths Different?

Garlic cloves and onion sets differ in size and growing structure.

Garlic cloves are normally planted completely beneath the soil.

Onion sets are commonly planted more shallowly.

Should You Cover Onion Tips?

Avoid burying ordinary onion sets deeply unless specifically directed by the supplier.

What Happens If You Plant Garlic Too Shallowly?

Cloves may become exposed or be disturbed before roots establish.

Can You Use a Dibber?

Yes.

A dibber makes it easier to create consistent planting positions.

How Far Apart Should Garlic and Onions Be Planted?

Spacing matters because each plant needs room to develop its bulb.

Garlic Spacing

Approximately 15 cm between cloves and around 30 cm between rows is a useful general guide.

Onion Spacing

Approximately 10–15 cm between onion sets and 20–30 cm between rows is commonly recommended.

How Much Space Between a Garlic Row and an Onion Row?

Allow approximately 25–30 cm as a practical starting point.

This helps reduce overcrowding and leaves room for foliage.

Can You Alternate Individual Garlic and Onion Plants?

You can, but it makes harvesting and crop identification more complicated.

For beginners, separate rows or blocks are usually easier.

What If You Want Large Onions?

Use the wider end of the recommended spacing range.

What If You’re Growing Elephant Garlic?

Allow additional room because elephant garlic produces larger plants.

Growing Garlic and Onions Together in Raised Beds

Raised beds are particularly useful for growing autumn alliums.

They can help improve soil structure, drainage and accessibility.

What Size Raised Bed Is Best?

A bed approximately 1.2 metres wide can work well because you can reach the centre from either side.

The length depends on the available space.

Can You Grow Both Crops in a 1.2 m × 2.4 m Bed?

Yes.

For example, you could divide the length into a garlic section and an onion section.

Alternatively, plant a small number of organised rows of each.

Is It Better to Separate the Crops?

Not necessarily.

However, keeping each crop in its own clearly labelled block makes harvesting simpler.

What Soil Mix Should You Use?

Choose a suitable mixture of quality topsoil and mature organic matter.

The bed should retain adequate moisture while draining freely.

Do Raised Beds Need Watering?

Yes.

Raised beds can dry out more quickly than ordinary garden soil during warm weather.

Check moisture regularly in spring and early summer.

Can You Grow Garlic and Onions Together in Pots?

Yes, although the container must be large enough.

For most gardeners, separate containers are easier to manage.

However, a very large trough or planter can accommodate both crops.

What Container Size Should You Use?

Choose a deep container with plenty of growing space and reliable drainage.

A large trough around 40–50 cm wide or more can be suitable for a small mixed planting, depending on its overall length.

What Compost Works Best?

Use a good-quality peat-free potting compost suitable for vegetables.

A suitable soil-based compost can help maintain structure in large containers.

How Closely Can You Plant?

Don’t reduce spacing excessively just because you’re using a container.

Allow sufficient room for bulbs and foliage.

Will Containers Need More Water?

Often, yes.

Compost can dry out faster than soil in an allotment bed.

Can Pots Stay Outside During Winter?

Suitable autumn garlic and overwintering onion varieties can generally stay outdoors.

Maintain good drainage and shelter containers during severe weather where appropriate.

How to Water Garlic and Onions Growing Together

Because both crops grow in similar conditions, watering them together is generally straightforward.

However, avoid treating every season the same.

Autumn

Natural rainfall is often sufficient.

Water new plantings if the soil is dry.

Winter

Avoid watering already wet soil.

Check that rainfall isn’t collecting around the bulbs.

Early Spring

Both crops begin growing more strongly as temperatures and daylight increase.

Check soil moisture during dry spells.

Late Spring

Healthy foliage is important for bulb development.

Avoid prolonged drought.

Early Summer

Garlic and onions may approach maturity at different times.

Adjust watering according to the condition of each crop.

Before Harvest

As bulbs ripen and foliage naturally dies back, reduce unnecessary watering.

What If Garlic Is Ready Before the Onions?

This is one reason separate blocks can be useful.

You can reduce watering around maturing garlic while continuing to care for onions that are still actively growing.

Gardening with Ben tip: Don’t water a mixed garlic and onion bed simply because one crop needs attention. Check which plants are still actively growing and which are beginning to mature.

What Is the Best Feed for Garlic and Onions?

Garlic and onions both need adequate nutrients to produce healthy foliage and bulbs.

However, you don’t need to constantly apply fertiliser.

Feeding at Planting Time

If the soil is already fertile and contains suitable mature compost, extra feeding may not be necessary immediately.

Feeding During Spring

If soil fertility is low, a suitable balanced fertiliser can support active growth.

Can You Use Onion and Garlic Feed?

Yes.

A fertiliser designed for allium crops may be appropriate for both onions and garlic.

Follow the manufacturer’s instructions.

Can You Use Chicken Manure Pellets?

Yes, but avoid overapplication.

Chicken manure pellets supply nutrients, including nitrogen.

Too much nitrogen can encourage excessive soft growth and may affect crop quality.

Is Tomato Feed Suitable?

Some gardeners use potassium-rich liquid feeds, but tomato feed isn’t automatically necessary.

Balanced nutrition is more important.

When Should You Stop Feeding?

Avoid unnecessary high-nitrogen feeding as bulbs approach maturity.

Should Both Crops Be Fed at Exactly the Same Time?

Not necessarily.

Their development may differ, particularly if you’re growing different varieties.

Assess the plants and soil before feeding.

How to Care for Garlic and Onions During Winter

Autumn-planted garlic and suitable overwintering onions are generally hardy.

However, winter care is still important.

Monitor Drainage

Waterlogged soil can cause roots or bulbs to deteriorate.

Check for Bird Damage

Newly planted onion sets can be pulled from the ground.

Remove Weeds

Weeds may continue growing during mild weather.

Avoid Excessive Watering

Natural rainfall is usually sufficient during winter.

Don’t Worry About Slow Growth

Both crops naturally grow more slowly in cold weather.

Watch for Pest Damage

Some allium pests remain relevant during autumn and early winter.

Inspect plants for unusual distortion or rotting.

Can Garlic and Onions Get the Same Pests and Diseases?

Yes.

This is the biggest disadvantage of growing them together.

Garlic and onions belong to the allium family, along with leeks, shallots and chives.

Several important pests and diseases can affect all of these crops.

Onion White Rot

Onion white rot is a serious soil-borne fungal disease.

It can cause:

• Yellowing foliage.
• Wilting.
• Root decay.
• Rotting bulbs.
• White fungal growth around the base of affected plants.
• Tiny black resting structures in advanced infections.

Why Is White Rot So Serious?

The fungus can remain in the soil for many years.

It’s particularly important to avoid introducing it into previously healthy growing areas.

Will Planting Garlic Next to Onions Prevent White Rot?

No.

Both can be infected.

What Should You Do If You Suspect White Rot?

Avoid moving potentially contaminated soil or planting material.

Don’t save affected bulbs for replanting.

Seek reliable identification and follow current disease-management advice.

Allium Leaf Miner

Allium leaf miner can attack garlic, onions, shallots, leeks and chives.

Its larvae feed inside plant tissues.

Affected leaves may become distorted, and damage can lead to secondary rots.

When Is Allium Leaf Miner Active?

In Britain, adult activity is often important during spring and again during late summer and autumn.

Can Insect-Proof Mesh Help?

Yes.

Fine insect-proof mesh can protect crops when installed before adults begin laying eggs.

However, ensure that pests aren’t already emerging from soil beneath the cover.

Onion Fly

Onion fly larvae can damage underground parts of onions and related crops.

Rust

Garlic and related alliums can develop rust, producing orange-brown pustules on leaves.

What Is the Best Protection?

Start with healthy planting material.

Maintain good drainage and sensible spacing.

Inspect plants regularly.

Use appropriate crop rotation.

Avoid moving contaminated soil between beds.

Why Crop Rotation Matters When Growing Garlic and Onions

Crop rotation means changing the location of related crops between growing seasons.

It’s a useful part of good allotment management.

Are Garlic and Onions in the Same Crop Rotation Group?

Yes.

Garlic, onions, shallots and leeks belong in the same allium rotation group.

Can You Grow Onions Where Garlic Grew Last Year?

It’s generally better not to treat these as different crops for rotation purposes.

They share pests and diseases, so changing from garlic to onions doesn’t provide a meaningful break from growing alliums.

How Long Should You Leave Between Allium Crops?

A three- or four-year rotation is a useful planning approach where space allows.

However, this isn’t a guaranteed disease-prevention period.

What About Onion White Rot?

This is particularly important.

Onion white rot can persist in soil for at least 15 years under some conditions.

An ordinary three- or four-year rotation won’t reliably eliminate it.

What Crops Can Follow Garlic and Onions?

Depending on your rotation plan, you might grow:

• Peas.
• Broad beans.
• Brassicas.
• Salad crops.
• Other vegetables from different crop groups.

The important thing is considering the entire history of the bed.

What If Your Garden Is Very Small?

Crop rotation becomes more difficult in limited spaces.

Focus on healthy planting material, good hygiene and avoiding known contaminated soil.

You may also consider suitable clean containers or growing areas where practical.

When Are Garlic and Onions Ready to Harvest?

Although they can be planted around the same time, their harvesting dates may differ.

When Is Garlic Ready?

Many autumn-planted garlic varieties are harvested during June or July.

Some mature earlier or later.

When Are Autumn Onions Ready?

Overwintering onions are commonly harvested during June or July.

Again, the actual date depends on variety and conditions.

How Do You Tell Garlic Is Ready?

Several lower leaves begin naturally turning yellow or brown.

Carefully lift a sample bulb to inspect its maturity.

How Do You Tell Onions Are Ready?

The foliage often begins yellowing and falling over naturally as bulbs mature.

Check whether the bulbs are firm and appropriately developed.

Should You Harvest Both Crops on the Same Day?

No.

Harvest each crop when it’s ready.

Don’t leave mature garlic underground simply because the onions haven’t finished growing.

Can You Remove One Crop Without Damaging the Other?

Yes, provided you’ve left enough spacing and work carefully.

Use a hand fork or garden fork to loosen the soil around the mature bulbs.

Avoid damaging neighbouring roots.

How to Harvest Garlic and Onions Correctly

The basic lifting process is similar, but you should keep varieties and crops separate.

Step 1: Check Maturity

Inspect the foliage and bulbs before lifting the whole crop.

Step 2: Choose Suitable Weather

Dry weather makes harvesting and initial drying easier.

Step 3: Loosen the Soil

Use a garden fork carefully.

Step 4: Lift the Bulbs

Avoid pulling hard on the foliage.

Step 5: Brush Away Loose Soil

Don’t bruise or damage the bulbs.

Step 6: Separate Garlic and Onions

Keep the two crops in labelled groups.

Step 7: Inspect for Problems

Set aside damaged or diseased bulbs.

Step 8: Cure Appropriately

Move the crops to suitable drying conditions.

Step 9: Store Correctly

After proper curing, keep healthy bulbs in cool, dry and well-ventilated storage.

Don’t assume garlic and onions will keep for exactly the same length of time.

Can You Store Garlic and Onions Together?

Both crops generally benefit from dry, well-ventilated conditions after curing.

However, their ideal storage life and requirements vary by variety.

Garlic Storage

Properly cured garlic is generally kept somewhere cool, dry and well ventilated.

Onion Storage

Storage onions need thorough curing and a suitable dry, airy location.

Can They Be in the Same Shed?

Yes, if conditions are appropriate.

Should You Store Them in Plastic Bags?

No.

Sealed plastic can trap moisture and encourage deterioration.

Should You Store Damaged Bulbs?

Use damaged but otherwise sound bulbs promptly where safe.

Discard any with significant rot or suspicious disease symptoms.

What Can You Plant After Harvesting Garlic and Onions?

If you harvest your autumn garlic and onions during early summer, you may have an opportunity to grow another crop.

This is a fantastic way to keep allotment beds productive.

Lettuce

Suitable summer and autumn varieties can provide fresh salads.

Rocket

Rocket is useful for relatively quick harvests.

Radishes

Many varieties grow quickly.

Pak Choi

Late-summer sowing is often useful.

Spinach

Late-summer or early-autumn sowing can work well.

Winter Salad Leaves

Hardy salad crops may keep the growing space useful into the colder months.

Should You Plant More Garlic Immediately?

You wouldn’t normally replant autumn garlic immediately after the summer harvest.

And because the bed has already grown alliums, think about crop rotation before deciding what to plant next.

Ten Common Mistakes When Growing Garlic and Onions Together

1. Using Ordinary Spring Onion Sets in Autumn

Choose varieties specifically recommended for overwintering.

2. Planting Both Crops at the Same Depth

Garlic cloves and onion sets normally have different planting depths.

3. Planting Everything Too Close Together

Allow adequate spacing for bulbs to develop.

4. Choosing Waterlogged Soil

Both crops require good drainage.

5. Planting in Too Much Shade

Garlic and onions generally grow best in full sun.

6. Forgetting to Label the Rows

Different crops and varieties may mature at different times.

7. Overfeeding with Nitrogen

Too much fertiliser doesn’t guarantee large bulbs.

8. Ignoring Shared Pests and Diseases

Both crops are vulnerable to several of the same allium problems.

9. Assuming Garlic and Onions Are Different Crop Rotation Groups

They belong to the same allium group.

10. Harvesting Both Crops at the Same Time Regardless of Maturity

Harvest each when the bulbs are ready.

Month-by-Month UK Garlic and Onion Growing Calendar

Month	Garlic jobs	Onion jobs
January	Check drainage and winter growth	Inspect overwintering sets
February	Plant suitable spring garlic	Prepare for spring onion sets
March	Remove weeds and monitor growth	Plant suitable spring onion sets
April	Check moisture and feeding	Maintain healthy leaf growth
May	Monitor scapes and bulb development	Water during dry spells
June	Check early garlic harvest readiness	Check overwintering onions for maturity
July	Harvest and cure mature bulbs	Harvest mature onions
August	Assess storage and plan varieties	Order suitable overwintering sets
September	Prepare soil and buy planting garlic	Plant suitable autumn onion sets
October	Plant autumn garlic	Continue autumn onion planting
November	Continue suitable garlic planting	Complete recommended autumn planting
December	Check drainage and protect young cloves	Inspect overwintering crops

These dates vary depending on variety, local climate and weather.

Frequently Asked Questions About Growing Garlic and Onions Together

Can you plant garlic and onions together?

Yes. Garlic and onions can grow successfully in the same vegetable bed when given suitable spacing, sunlight and drainage.

Are garlic and onions good companion plants?

They have compatible growing needs, but there isn’t strong evidence that planting them together automatically improves yields or prevents pests.

Can garlic and onions grow in the same raised bed?

Yes. Raised beds can provide excellent conditions for both crops.

Can you plant garlic and onion sets in October?

Yes, provided you choose garlic and overwintering onion varieties suitable for October planting.

Can you plant garlic and onions together in November?

Often yes, depending on the varieties and soil conditions.

Should garlic and onions be planted at the same depth?

No. Garlic cloves are generally fully covered, while onion sets are commonly planted with their tips just visible.

How far apart should garlic and onions be planted?

Allow approximately 15 cm between ordinary garlic cloves and 10–15 cm between onion sets.

How far apart should garlic and onion rows be?

Around 25–30 cm between different rows is a practical starting point.

Do garlic and onions need full sun?

Yes. Both generally perform best in sunny positions.

Can garlic and onions grow in clay soil?

Yes, provided the soil drains adequately.

Do garlic and onions need the same fertiliser?

They have similar nutrient needs, and an appropriate balanced allium fertiliser can be suitable for both.

Can you use chicken manure pellets on garlic and onions?

Yes, but avoid excessive nitrogen and follow the product instructions.

How often should you water garlic and onions?

Water according to soil moisture and weather, particularly during dry spring conditions.

Do onions protect garlic from pests?

Not reliably. Several pests can attack both crops.

Does garlic protect onions from onion fly?

Don’t rely on garlic planting as a method of onion fly prevention.

Can garlic and onions both get white rot?

Yes. Onion white rot is a serious disease affecting both crops.

Can you grow onions after garlic in the same soil?

It’s generally better to rotate away from alliums because onions and garlic share pests and diseases.

Are onions and garlic in the same crop rotation group?

Yes. They’re both alliums.

Can you grow shallots alongside garlic and onions?

Yes, with suitable spacing and growing conditions, but shallots share many of the same pest and disease risks.

Can you grow elephant garlic beside onions?

Yes, but elephant garlic needs considerably more room.

When should garlic and autumn onions be harvested?

Many autumn-planted garlic and overwintering onion varieties are harvested during June or July.

Can garlic and onions be harvested together?

Only if both crops are mature. Otherwise, harvest them separately.

Can you store garlic and onions together?

They can be kept in the same suitable dry, ventilated storage area after curing, though their storage lives vary.

What can you plant after harvesting garlic and onions?

Suitable follow-on crops include lettuce, rocket, radishes and seasonal salad vegetables.

Final Thoughts: Is Growing Garlic and Onions Together Worth Trying?

Growing garlic and onions together can be a fantastic option for UK gardeners, particularly if you’re making use of your allotment beds during autumn.

Both crops enjoy similar growing conditions.

They prefer sunny positions, fertile soil and good drainage, and suitable varieties can be planted during the same season.

That makes it easy to organise your autumn planting.

However, the most important thing to remember is that garlic and onions belong to the same plant family.

They can suffer from many of the same pests and diseases, so planting them together isn’t a way to prevent allium problems.

You still need healthy planting stock, good soil hygiene and sensible crop rotation.

If you’re growing these crops for the first time, I’d recommend keeping them in clearly labelled rows or separate sections of one raised bed.

That will make planting, feeding, watering and harvesting easier.

And don’t forget that garlic cloves and onion sets are planted at different depths.

Once your crops are established, keep the bed reasonably weed-free, monitor soil moisture and check the plants throughout spring.

Then, when summer arrives, harvest each crop at the appropriate stage.

After curing and storing your bulbs properly, you’ll have delicious home-grown onions and garlic ready to use in the kitchen.

There’s something incredibly rewarding about knowing that the onions and garlic you’re cooking with started as small sets and cloves planted months earlier.

So if you’ve got some space in your vegetable garden or allotment this autumn, why not try growing garlic and onions together?

Keep smiling, keep shining, keep gardening with Ben!