Allium sativum, Amaryllidaceae family
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!
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.
- 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
Garlic cloves plantedBulbs ready to harvestAutumnEarly summerWinterEarly to midsummer, smaller harvest
- 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!
Pattern of growth
There are small variations according to the two main types.
The two types of garlic
Hardnecks 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.
Softnecks 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.
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.
- 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.
I don’t mention soil a lot in these lessons 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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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’.
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.
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.