Garlic

Allium sativum, Amaryllidaceae family

Garlic originated somewhere between the Middle East and Central Asia, thousands of years ago.

Introduction

Garlic originated somewhere between the Middle East and Central Asia, thousands of years ago. Now it’s found in cuisine worldwide, although it is not as widespread as onions. In fact, 80% of the world’s garlic is grown in China.

It’s closely related to onions, leeks, chives etc., and has many close relatives in wild or non-cultivated forms. Wild garlic, also called ramsons or wood garlic, is Allium ursinum. When I planted garlic in my Newmarket garden in 1983, my father was horrified because he assumed it was wild garlic!

An impressive garlic harvest at summer solstice

Wild garlic likes shady and moist conditions, and is often found near riverbanks. It has pretty white flowers, similar to garlic chives (Allium tuberosa). The leaves make fantastic pesto.

Ornamental garlic, also called Tulbhagia and ‘society garlic’, is in the same Amaryllidaceae family. It originated in South Africa and decorates gardens in temperate climates. The purple flowers in early summer are best cut off and composted once flowering finishes, because they can become a prolific weed if you allow them to drop their seeds.

Garlic withstands cold temperatures well; 19th March under a blanket of snow – these plants were unaffected

Checking for maturity in early June – peeling a slightly immature, yet edible and tasty garlic

A harvest of elephant garlic on the right, and normal garlic on the left

Harvest period

Days from seed to first harvest, sown/planted in September and harvested in June: 260
Sown/planted in January, harvested early to mid-July: 180

Best climate is cool to warm, not too wet, and there must be frost in winter to enable bulbs to differentiate into cloves.

Why grow them

My customers tell me that Homeacres garlic is often more pungent than the garlic of commerce. A little goes a long way, and raw garlic is excellent for the health.

Garlic stores so easily. From just one sowing, and one resulting harvest, you can enjoy it for almost the whole year.

The sulphurous compounds, which give such a potent flavour, are probably a defence mechanism used by the plants to prevent them from being eaten. This is why crushed garlic can be a useful pest deterrent, against slugs for example.

When I show garlic on social media, the posts attract many comments and questions. People are keen to grow it, not least because:

It’s easy to grow and store.
You don’t need much to bring fantastic flavour and health into your life.
You can grow a worthwhile amount in containers.
Your harvest is your seed for planting a few months later!

Early April – at six months old, these garlic plants are on the small side

Another crop of garlic in early April, looking okay overall, but a few plants are showing yellow leaves and weak stems

1st June – these immature Early Purple garlic plants are showing strong growth, although there’s too much rust on the leaves

Pattern of growth

There are small variations according to the two main types.

The two types of garlic

Hardnecks

‍These make slightly smaller bulbs than softnecks, with larger and fewer cloves in each one. The cloves are easier to peel than those of softnecks.

Harvest is two to three weeks later than that of softnecks, and they can store until early spring.

Hardneck garlic grows a flower stem by mid-spring, and if you leave it to grow it will flower beautifully by early summer. The stem is also called a scape, and is delicious when harvested as a tender stem, before the flower bud on top has swollen much.

To eat scapes, just snap off the main length of stems in mid-spring when still tender. They are tasty roasted or sautéed. The plants then continue to grow without any flower stem, resulting in slightly larger bulbs.

Early October – softneck on the left and hardneck on the right

Softnecks

These make mostly larger bulbs, and with more differentiation into cloves of variable size.

They mature in early summer mostly and store for up to 11 months, depending on the variety and storage location.

Softnecks never make a flower stem.

By 10th May, the garlic is showing strong growth compared to growth shown in the photo above

The same bed of garlic after we pulled half of it on 11th June, before the second harvest on 13th June; this was originally planted in September

One hour after harvest on 13th June – you can see that the roots have been left on and cleaned

Video

A variation

A third type is not garlic! It’s often called ‘elephant garlic’ and is a way to impress your friends. It’s actually a leek in bulb form (Allium ampeloprasum) and tastes excellent when roasted. The cloves are four to five times heavier than even the larger softneck varieties.

The flavour is mild, not pungent, and the texture is creamy.
Harvest in mid rather than early summer.

Plant in early autumn, from the large cloves of your harvest. You can also plant small ‘bulbils’, see the photo below, which adds a year to the harvest. Bulbils grow into cloves in year one, thence to bulbs in year two.

Elephant garlic makes a flower stem, just like hardneck garlic. You can harvest it in late spring as a scape.

Three stages of elephant garlic – mature bulb, one solve of a mature bulb, and a bulbil that was attached to a clove

Planting a clove of full-size elephant garlic using a dibber

Mid-June – see how elephant garlic leaves look like leeks; see also onions, sorrel, parsnips, carrots and artichokes

Varieties

Flavour-wise, I like Solent Wight (softneck) which, along with Mersley Wight, stores really well. It grows smaller bulbs than, say Provence Wight.
For an early harvest, even in late May, try Early Purple Wight. Eat it before the end of autumn, because it sprouts in storage by early winter.
A good hardneck for cool climates is Doocot, which originated in Canada and grows especially well in cold conditions (supplier – Really Garlicky Co.).
From your harvest of bulbs, keep the largest ones for seed. Separate these into cloves to re-plant each autumn.

What to expect

First leaves can appear any time from autumn to late winter, depending on the variety.

Don’t worry if you don’t see any leaves until even late winter. Your plants will be developing lots of roots before leaves appear. During spring you will be amazed at the speed of growth.

If, by mid-spring you are not impressed by strong, dark green leaves, you could top dress the bed with some more compost, for moisture retention as much as nutrients.

Garlic really goes for it in the spring, and any extra compost applied in April will also help the growth of your succession planting, for example beetroot after the garlic harvest.

The soil

I don’t mention soil a lot in these guides because I assume you are no dig. It makes garlic and all vegetable so easy to grow – see the comparison photos below from Inverness in North Scotland, latitude 58° North.

If you are dig and till, you will need to do extra cultivation and, above all, weeding.

NO DIG garlic in Inverness, growing in no dig beds on 26th May, after being planted in December; this shows how hardy the plants are

DIG In late May – this garlic was planted in October after rotavating manure into the soil

30th May – my polytunnel garlic is bigger than the plants growing outside; on the right I’ve mulched tomato plants with miscanthus and seaweed

If your soil is heavy and drains slowly, beds slightly raised with compost make a difference. They do not need to be more than 7 cm/3 in high, nor do they need wooden sides, as I show in the photos below.

Flooding around my newly planted no dig garlic bed in November, at Lower Farm my previous garden

The same garlic bed is now much drier in April, with no digging or soil tillage

Suitable for containers/shade?

Both are possible, so you can grow garlic in a pot in the shade. Or in the sun!

Use a medium-sized container, say 30 cm/12 in wide – this will be able to grow six plants.
Garlic makes efficient use of precious container space, because part of its growth is during winter.
After, or even before the harvest, you can transplant, say, beetroot, kale and salad.

Sow and propagate

Garlic grows from cloves rather than seeds. Nonetheless, we talk about ‘seed’ garlic and ‘sowing’ garlic. Sometimes we also use the term planting and, for either word, one is putting cloves in the ground, not seeds.

Cloves germinate in three to twelve weeks, depending on when they were sown and winter temperatures.

Sowing time

Autumn is absolutely the best time to sow garlic. Reasons include larger and slightly earlier harvests, plus a better differentiation of bulbs into cloves. Sowing can happen from September.

Spring sowing is possible, but it must be early spring, and only in climates where there is still some cold weather after sowing time. Cold means one or two nights below freezing point. Without the cold, your harvest may be of medium-sized bulbs with exactly one clove in each.

Spreading compost over freshly planted garlic

Preparing cloves to sow

You need to separate cloves for sowing from their bulbs. Use the fingers of both hands to rub downwards on a bulb, which eases off its outer layers of white skin to reveal the cloves around its edge. Just pull them all loose.

The outer cloves are larger and best for sowing, in that they usually grow slightly larger bulbs. Any large cloves are good to sow, and you can expect about ten per bulb, or six to eight for hardneck garlic.

How to sow, and spacing

Use a long, wooden dibber to make a hole 3–4 cm/1.5 in deep for each clove. Pop them in with the wide, hard end downwards and the pointy end upwards. Spacing can be as close as 10 cm/4 in each way.

Fill holes after sowing with fingers, the dibber, or a rake.

For large harvests, space at 10 cm/4 in, in rows across the bed, and with 25 cm/10 in between each row. This makes hoeing easier in spring, if your compost or soil has many weed seeds.

Kate lightly raking the garlic planted in the dibbed holes, so I could then spread compost on top

30th December – emerging shoots of Doocot garlic peeking through the layer of compost; these were sown on 12th November

The same garlic on 17th January, even after frosts of 6 °C/21 °F and an average day’s maximum temperature of 5 ° C/41 °F

Bed prep

Feeding soil life with no dig fits in nicely with sowing garlic in the autumn. Usually you sow after clearing the previous vegetable, together with any weeds, often 10–12 months from when you last spread compost.

Sow garlic as above, but a little less deep.
Then spread 2.5 cm/1 in of compost for the upcoming year, on top of the new planting.

In areas that are new to no dig, use slightly more compost and apply some to paths as well, once weeds have died thanks to the first-year-only mulch of cardboard.

These November beds were planted with garlic and then covered with well-decomposed cow manure

The same beds on 30th May, after a mostly dry spring – garlic at the front and broad beans behind

Harvesting the garlic a little late, on 1st July

Transplant, interplant

Transplant

It’s quicker not to raise transplants because cloves of garlic grow so easily and reliably, without any propagation phase. Also, they go into warm soil in autumn.

If you wish to raise garlic plants, I would use a 7 cm/3 in pot and sow in early autumn, for transplanting six to eight weeks later. This is useful if a previous vegetable is maturing where you want to plant the garlic.

Or you could pop cloves into dibbed holes, between existing vegetable plants.

Interplant

Garlic is ideal for interplanting, in many ways.

Either you can transplant or sow other vegetables between garlic plants, about one month before the garlic harvest – beetroot, carrots, kale and broccoli all work fine as interplants between garlic, in very early summer.
Or you sow garlic at the same time as other new plantings, such as salads for winter leaves. This can be under cover as well as outside.

With a little practice, you can work out combinations that suit your harvest desires. The photos below give you some pointers, such as the lovely combination of garlic and parsley. These two plants not only grow well together but eat well together, often a feature of successful companion planting.

20th April – an interplant of radish between October-sown hardneck garlic in the Small Garden

January – garlic emerging between parsley plants in the polytunnel

Garlic and parsley growing well together in the polytunnel in March

10th July – the Solent Wight garlic on the right is late to harvest, from a late sowing

21st July – the harvest, with interplanted kale about to grow strongly

Garlic under cover

I find that interplanting allows me to grow easy and successful garlic harvests under cover. The garlic uses ‘free space’.

I don’t feel it would be worth using precious polytunnel space to grow only garlic, when of course you can grow it outside. Yet, when grown under cover in a damp climate such as here, garlic grows much bigger, probably thanks to the lack of water on its leaves in spring rainfall. As far as I can tell, this is the main cause of rust on leaves.

The photos below show you how it works. We sow garlic in October, between salads that have just been transplanted. I give no extra space to the garlic, none at all. Hence I call it a free harvest, because it uses existing space, soil goodness and water.

Actually, we do give the garlic some extra water in spring, when bulbs are swelling fast. But it receives no extra compost or feed, and its growing needs fit beautifully with both sets of interplants.

Garlic plants only grow to a small size in winter and early spring, while the salad plants are producing many leaves.
After clearing the salads, we can transplant cucumbers and tomatoes in their normal spacing on both sides, while the garlic continues to grow between them.
We transplant marigolds between the garlic.
About one month after transplanting the tomatoes etc., we harvest the garlic before it’s overshadowed by the new summer plantings.
Sometimes I grow garlic in the same space as the previous year. There is absolutely no four-year rotation, but a one-year rotation is good where possible.

2018

9th May – garlic interplanted between salads in October; the salad plants had cropped all winter; we were about to twist out these lettuce and endive

Later on the same day – we had cleared winter salads and spread compost around the garlic; the tomato strings were also ready for the new planting

11th June – we harvested garlic in the tunnel, from between the tomatoes and marigolds

2019

17th April – interplants of lettuce and garlic at 22 cm/9 in spacing; the Grenoble Red lettuce would continue cropping until June if we had not needed the space before then

By mid-May, we had cleared the lettuce and spread the annual mulch of compost around the garlic

Freshly pulled garlic with trimmed roots and the skins removed, to store in the house as clean bulbs

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Transplant

It’s quicker not to raise transplants because cloves of garlic grow so easily and reliably, without any propagation phase. Also, they go into warm soil in autumn.

Or you could pop cloves into dibbed holes, between existing vegetable plants.

Interplant

Garlic is ideal for interplanting, in many ways.

Either you can transplant or sow other vegetables between garlic plants, about one month before the garlic harvest – beetroot, carrots, kale and broccoli all work fine as interplants between garlic, in very early summer.
Or you sow garlic at the same time as other new plantings, such as salads for winter leaves. This can be under cover as well as outside.

Garlic under cover

I find that interplanting allows me to grow easy and successful garlic harvests under cover. The garlic uses ‘free space’.

Garlic plants only grow to a small size in winter and early spring, while the salad plants are producing many leaves.
After clearing the salads, we can transplant cucumbers and tomatoes in their normal spacing on both sides, while the garlic continues to grow between them.
We transplant marigolds between the garlic.
About one month after transplanting the tomatoes etc., we harvest the garlic before it’s overshadowed by the new summer plantings.
Sometimes I grow garlic in the same space as the previous year. There is absolutely no four-year rotation, but a one-year rotation is good where possible.

2018

2019

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Water

In dry springs, give water. The initial watering may be needed about six weeks before harvest, and then every week until a week or two before harvest. That is all.

In dry climates, and on tilled or sandy soil, you need to water more.

Extra mulch to retain moisture?

This is worthwhile where rainfall is limited. Apply a mulch of hay or straw straight after sowing the garlic.

Leaf removal

It’s not necessary to tidy old leaves, but it can help when rust is a problem in the spring. I find that twisting off lower leaves, which are showing signs of yellow and orange spots of rust, improves the final harvest.

You can safely put these leaves on a compost heap – see below.

Harvest times and methods

How to judge readiness

Whatever the weather, you can expect to harvest garlic in early rather than late summer. The question is whether to harvest in early or late June, and it’s absolutely NOT about waiting for leaves to turn yellow.

If you wait that long, probably until early August, there are two undesirable results:

Bulbs will have lost their outer skins by the time you finally harvest them. The outer cloves are now unprotected by a nice white sheath, there will be soil between them and storage is compromised.
You lose time for second plantings, most of which need to be in the ground before midsummer.

Harvest bulbs to store when leaves are still mostly green. In late spring, check for swelling of bulbs below soil level – you may see and feel cloves protruding, but still under the white outer skin. In this case, harvest is close.

Outdoor harvests here are currently 12–20th June, depending on the preceding weather. In 2020, we harvested outdoor softneck garlic on 11th June, a week after the undercover harvest of 4th June. Both dates were my earliest ever.

Hardnecks and Elephant Garlic are ready to harvest about three weeks later than softneck.

The importance of timing harvests – these were from the same sowing, but the one on the right was harvested two weeks earlier, whilst the other was left in the ground

Harvesting

An early option is to harvest garlic when immature and green, as you would a salad or spring onion, during late spring. At this stage, you can usually pull the garlic out without using a tool.

For the main harvest of bulbs, you may need a trowel to cut the roots under each bulb. Be careful not to damage the bulb itself, which is soft and juicy. Then pull gently upwards, with as little soil disturbance as possible.

Checking to see if the garlic is swelling, just a few days before harvest

13th June, with a garlic harvest from under cover among the tomatoes behind; see how large the garlic has grown, and with little rust

A garlic crop outside on 18th June, from between plantings of climbing beans in this bed

Storing

Harvested garlic is moist and has a green stem. It saves work later when, at harvest time, you peel off the dirty outer skin to reveal a pristine white bulb. Also trim off excess roots and any compost or soil attached to them.

Lay the plants on a pallet or tray, under cover and where there is air movement. Or they could be outside in the sunshine, but not for too many days – this can cause pink discolouration, and intense sunlight can even soften the bulbs.

Once the stem and leaves are mostly dry and yellow, you can plait or bunch them together to hang in the house. They store better in dry warmth, compared to an outdoor shed or garage, for example.

4th June – straight after harvest from the polytunnel, these garlic still have dirt on them

The same garlic an hour later, after cleaning and trimming the roots

Five weeks later on 7th July – we plaited the garlic and hung it in the conservatory, for use any time until mid-spring

Saving seed

It’s absolutely fine to save your own garlic to resow/replant, despite what you may read to the contrary. I have done this for nearly four decades and have never met a problem. I even plant cloves of bulbs that have suffered a fair amount of rust on the leaves.

They grow fine because rust is not transmitted through soil or plants – it tends to happen more in suitable weather conditions, as with late blight on potatoes and tomatoes.

For seed garlic, simply use your finest bulbs. Set them to one side at harvest time, to use for sowing.

Video:Garlic harvest, then preparing quickly for replanting

Potential problems

All the possible problems listed here, apart from garlic rust, are general to other alliums that we grow, such as leek and onion.

Allium leaf miner (Phytomyza gymnostoma)

Allium leaf miners are horrible pests which I hope you don’t suffer. They have been in the UK since about 2002 and, if you garden in the East Midlands and Southeast England, it’s likely that they are present. I have heard they are near to here now.

A cover of mesh from February to early June can help, and again from September to November.

These timings are to protect allium plants from the two generations of egg-laying flies, which are present firstly in early spring and then again during mid to late autumn.

The white maggots look similar to those of leek moth. They can bore into foliage, stems or bulbs for two weeks or so, before turning into brown pupae. Pupation occurs within stems and bulbs, in both summer and winter after the respective hatchings.

From any leaves and plants, the 3mm/0.1 in brown pupae can end up in the soil. They hatch as small flies in the spring.

I would feel safe putting all damaged leaves and plants in the middle of a compost heap, with heat of say 50 °C/122 °F plus, approximately.

Leek moth (Acrolepiopsis assectella)

If you are unlucky and have these in your area, their first hatching in late spring can bore into and eat garlic stems. The caterpillars are small and mostly stay well hidden inside new leaves, right in the middle.

At first, there is no damage visible.

Prevention is through covering garlic with mesh, from early spring.
You may be able to find and extricate the little white caterpillar, by cutting into a damaged plant with a knife.

Early June – I found a leek moth maggot, or caterpillar/worm, in the stem of some garlic whose leaves were looking yellow

Rust (Puccinnia allii)

By the end of April/mid-spring, you could be noticing orange spots on some lower leaves. If these become common, twist off those damaged lower leaves to reduce the spread of rust spores. Leaf removal is the only way I know to reduce it, apart from growing garlic in a polytunnel or greenhouse.

There is always less rust on leaves of garlic under cover compared to those grown outdoors, and, partly for that reason, the harvests in early June are bigger.
Probably there is less rust under cover because it is caused by frequent rain and water on leaves in the spring. Rather like late blight being caused by frequent rain on potato and tomato leaves in the summer.
If it was wet in early spring and rust has spread over all the leaves, making them mostly yellow, harvest earlier than normal.

In 2008 and learning about rust – I should have harvested this garlic two weeks earlier, as the bulb skin was decaying; at least the surrounding carrots were growing nicely

Later the same day, after lifting the garlic bulbs out – they were small and had some decay on their outer skins

Mid-June – some rusty garlic at Homeacres; fortunately this didn’t spread to the spring onions

White rot (Stromatinia cepivora)

This fungus is specific to allium plants. It shares the ‘white rot’ name with beneficial fungi called Phanerochaete chrysosporium, which decompose the lignin in wood and also many toxic chemicals.

Stromatinia exists in soil for five to fifteen years, as dormant sclerotia. They spring to life in temperatures of 15–20 °C/60’s °F, should they detect allium roots nearby. Their longevity makes white rot a persistent problem, once it is present.

Signs of damage are onions and garlic falling over in early summer, sometimes with bright yellow leaves, and all roots dying fast. Leeks suffer too, but more in autumn than summer, because white rot is mostly dormant in soil above a temperature of 20 °C/68 °F.

Check the reputation of seed suppliers.
Do not spread soil from infected areas, and wash tools where appropriate. No dig reduces the spread of white rot – see the quote below.
Leave a gap of three to five years before growing alliums in a bed where there is infected soil. When taking over an allotment, you may have to discover where there is white rot the hard way. It shows only as damage to plants – it is not visible in the soil.
Like clubroot, it’s more likely prevalent where soil has been poorly looked after, on old allotment sites.

An observation from Jayne Arnold, a market grower in central England at Oxtons Organics. She wrote in an email on 20th November 2020, after their third year of being no dig: ‘For the first time in 30+ years we have not had a single leek with white rot. A disease we inherited and which obliged us to practice eight-year rotations, to enable us to grow alliums’.

And finally

Clear

Your ground is clear once you have harvested garlic and pulled any weeds. If you used a trowel to lift bulbs, making the surface lumpy and uneven, best walk on the bed to firm the soil down, then rake lightly to level.

Dibbing holes straight after the garlic harvest – it’s hard work in the dry soil

In high summer, straight after the garlic harvest, we have transplanted broccoli and kale into the no dig dry soil, and watered in just around the roots of each transplant

Ten weeks later on 7th September – strong growth from the brassicas, with chicory and leeks on the right

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Follow with

Good plantings to follow garlic include almost any brassicas. Also beetroot, carrots, dwarf French beans, chard and radicchio, to name just a few possibilities. I often sow carrots or transplant beetroot between rows of garlic.

There is no need to apply any feeds or compost before making these new plantings.
You may also have been able to set them between garlic, as much as four weeks before its harvest.

2nd October, and the second plantings are thriving after we harvested the garlic in late June

Succession planting – with the first and second crops on 6th July; we had transplanted the beetroot 16 days earlier

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