How to grow garlic and best varieties

Flavoursome garlic is an essential ingredient in so many recipes. 

Easy to grow in the garden, it doesn’t take up too much space and it can be started off in the autumn or late winter in the ground or in pots.

The researchers are Which? Gardening magazine grew  lots of varieties at our trial grounds to find the best ones. We also share our tips about how to plant garlic to get great harvests.

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Best garlic varieties

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The difference between softneck and hardneck varieties, plus elephant garlic

Softneck varieties do not usually produce a flower shoot. They generally produce tighter bulbs, keep for longer and contain more cloves than hardneck types.
Hardneck varieties often produce a flower shoot, or ‘scape’, during early summer. The flower head is sterile and doesn’t produce seed. Cut these scapes off to help the bulbs well. When harvested, the bulbs are generally looser and the cloves are arranged around the woody remains of the stalk. Hardneck varieties are said to have a stronger flavour.
Elephant garlic, which we didn’t include in our trial, is not strictly a garlic but is more closely related to leeks. It produces huge bulbs, with a few, very large, mild-tasting cloves.

Can I plant supermarket garlic?

Supermarket garlic is often imported from countries around the world and there is a strong chance it could carry viruses; some of which may be introduced to the UK. These viruses could then be spread by aphids to other growers, including farmers. This is why it's important to always buy garlic bulbs that are sold for planting.

When to plant garlic

Choose a sunny site and fertilise the soil well before planting. Garlic can be planted throughout the winter from October to February, but it’s best to get it in the soil before it becomes frozen or sodden with rain. A period of cold is said to help it. 

Break up the bulb into cloves and plant these about 2-3cm deep, with just the tips protruding from the surface of the soil. If you have problems with birds plucking the cloves out, plant them deeper and firm the soil around the cloves.

Plant cloves 15cm apart in rows that are 20cm apart so you can weed between the young plants easily.

Alternatively you can grow garlic in pots. These can be put in a cold greenhouse if you'd like to avoid rust disease.

Help your plants with a recommended soil improver

Caring for your garlic

Water the garlic during any dry spells, especially during spring when it’s in full growth. You can give plants a boost by scattering food, such as growmore, around them in spring.

Like onions, garlic don’t compete well with other plants, so weed regularly. 

If the plants start to form flower stalks (scapes,) cut them off. They’re good to eat in stir-fries or salads.

Try a Best Buy watering can

How and when to harvest garlic

Harvest in: June to July

Harvest the bulbs in June or July when the leaves turn yellow and start to fall over. The cloves should be fully formed and the skins papery.

Dry the garlic in a sunny spot or indoors and store as plaits or in bags in a cool, dark area.

If you’d like to harvest your garlic earlier, you’ll pick what is known as wet or green garlic. It has a single bulb and a milder flavour, and can be used in cooking much like a leek.

Discover Best Buy garden kneelers

Common growing problems

Rust

Rust is a fungal disease that causes rusty-orange blotches on the leaves. It’s prevalent in warm, moist weather. Severe infections can make the garlic bulbs very small, but this is rare and slight infections will affect only the outer leaves, which can be peeled off, and will usually disappear when the temperature drops in winter. There aren’t any chemical controls, so your best defence is to dispose of any affected leaves, ensure your plants aren’t crowded to improve airflow and grow your garlic in a different spot each year. Alternatively grow it in a cold greenhouse.

Onion fly

Onion fly lays its eggs near the base of the plant. The larvae feed inside the bulb or lower stem just above the bulb of seedlings. When they have finished with one seedling they move on to an adjacent one, so seedlings tend to be killed in patches. In older plants they feed in the bulb and work upwards. Eventually, the lower part of the bulb is so damaged that the resulting pale, wilting foliage is easily pulled off. The outer leaves tend to fall to the ground, while the inner leaves remain vertical, but are soft and no longer crisp. When you look closely at the bulb it is rotting, smelly and can have as many as 30 maggots in it. Even lightly affected plants are unfit for harvesting. Typically, the first sign of onion-fly attack is that the leaves of established plants begin to yellow. Affected seedlings tend to die in patches. These patches can spread along the row.

Where onion flies are a recurring problem, on allotments for example, covering with fleece or insect-proof mesh to protect against the early generation is worthwhile. 

White rot

White rot is caused by a fungus that destroys the roots, killing the plant. It then produces resting bodies that can last for many years in the soil.

Onions, shallots, garlic and leeks all suffer from this disease. Spring onions and overwintered onions seem particularly susceptible. 

Look out for yellow and stunted plants in May and June among your overwintered onions, and later in the other onion-family crops. When you pull up sickly plants, check for a white/grey mould around the base. In advanced cases, you will see black, pinhead-sized, regular spheres. These are the sclerotia, or resting bodies, that will carry the disease from one crop to the next.

When you see white rot, remove the plants and a few inches of surrounding soil. Burn or bin them. This will make sure that you don't add more sclerotia to the soil.

Avoid transplants grown in soil-based compost. Gather and use an attacked crop as soon as you can, as damaged bulbs will be unusable and won't store well. There are no chemicals available to gardeners to control this disease, and there are no resistant varieties.

Leek moth

The young caterpillars of leek moth burrow between the surfaces of the leaf, like a leaf miner, creating brownish-white patches. As they get bigger, they bore down into the shaft of the leek, or the bulb of the onion, causing more substantial damage and allowing in rotting fungi and bacteria. At this stage, the vegetables tend to develop yellow leaves and go slimy. 

The caterpillars are yellow-green with legs at the front and fleshy pro-legs at the back, they have a dark head and dark raised spots with hairs. They grow from 1mm, when newly hatched, to 10mm. As you might expect, leek moth is best known as a pest of leeks, but it can also attack chives, garlic, onions and shallots. There are two generations of caterpillars a year in the UK, in spring and late summer. The first attack is often mild, especially after a cold winter. The second one is the most damaging, and hot summers tend to favour the pest and make the problem worse.

Remove any caterpillars you find and cut back badly damaged foliage. Leeks can often recover and still produce a reasonable crop; onions are less likely to. Undamaged parts of the leeks can still be used. To avoid this problem, cover your leeks with fine insect-proof mesh when you plant them.

How we test garlic

We selected 16 varieties of garlic, including new varieties, old favourites, and a mix of softneck and hardneck types. The researchers for Which? Gardening magazine planted all varieties at our trial site at Capel Manor in north London in autumn in a bed that had been fertilised with chicken manure pellets. We planted them with the tips of the cloves just showing above the soil. 

In early July the following year, we harvested the bulbs and left them to dry in a greenhouse before weighing and assessing the crop. To taste each variety, we roasted them in separate containers with a little light olive oil.