Garlic

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.

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.

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.

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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.

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.

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

2019

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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.

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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.

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.

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.

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.

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’.

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