RHS Growing Guides
How to grow garlic
Our detailed growing guide will help you with each step in successfully growing Garlic.
Getting Started
A member of the onion family, this staple of Mediterranean cooking is simple to grow in a warm sunny site with well-drained soil. It’s grown from cloves, which are best planted in late autumn, and is ready to harvest the following summer.
Garlic is usually planted in autumn, for harvesting in early summer
Simply keep weeds at bay and water in dry spells, and you’ll be harvesting your own garlic from early summer onwards, depending on the variety. Garlic stores well for several months, so you can grow plenty to use as needed, and benefit from garlic’s many health-boosting properties.
Month by Month
Jobs to do now
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Choosing
There are two main types of garlic – hardneck and softneck.
Hardneck garlic:
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Produces bulbs with fewer, larger cloves
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Has a stronger, more interesting flavour
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Stores only until mid-winter
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Prone to bolting (flowering), which can lead to a smaller bulb that won’t store
Softneck garlic:
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Produces smaller, more tightly packed cloves
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Stores for longer – if planted in autumn it will keep well into the following winter, if planted in spring it will keep until the middle of the following spring
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Unlikely to bolt, except in poor growing conditions
Within these two categories, there are many varieties to choose from, with different harvesting times, storage lengths, bulb sizes and flavours. Look in particular for varieties with an RHS Award of Garden Merit (AGM), which shows they performed well in growing trials.
Elephant garlic
Elephant garlic (Allium ampeloprasum) is often sold as garlic, but is actually more closely related to leeks. It produces a big bulb with a small number of very large cloves, which have a mild flavour. It needs a long, warm growing season to produce a good crop and is best planted in October.
The cloves sometimes don’t divide, producing just a slightly larger single-clove (solo) bulb. Early planting often reduces the occurrence of solo bulbs. You can either eat solo bulbs or re-plant them the following autumn – they will usually go on to produce a multi-clove bulb.
Different garlic varieties offer variations in flavour, harvesting time, bulb size and colour
What and where to buy
Named garlic varieties are widely available in autumn and spring, in garden centres and online, with several specialist suppliers offering a particularly wide choice. Planting garlic bought in a supermarket isn’t recommended and may lead to a disappointing crop, as it could be a variety that needs a warmer climate or be infected with a virus.
Recommended Varieties
A soft neck variety with pure white bulbs. Has a strong flavour but light, elegant aroma which makes it ideal for a variety...
A well known and reliable soft neck variety. Large white bulbs with a fairly mild, but still rich flavour.
Originally from Lautrec in France, this is a classic hard necked variety. White skinned bulbs with deep pinky-purple cloves.
Preparing the Ground
Raised beds are a good option for garlic, as they tend to provide well-drained conditions
Prior to planting, remove any weeds, then improve the soil’s structure, moisture retention and nutrient levels by digging in organic matter. Apply about two bucketfuls of well-rotted (not fresh) manure or garden compost every square metre/yard. You can also add a high potassium general fertiliser, such as Vitax Q4, at a rate of one handful per square metre/yard. If organic matter was not applied, double the amount of fertiliser.
To reduce the need for weeding later, you could cover the soil with weed-suppressing membrane, then plant the cloves through slits.
Planting
Planting in the ground
Garlic is usually planted in late autumn or early winter, as it needs a period of cold – most varieties need one to two months at 0–10°C (32–50°F) for good bulb development. However, a few varieties are suitable for planting in early spring.
Once you’ve prepared your planting site (see above), carefully split your garlic bulbs into individual cloves. Be sure to plant them the right way up, with the flat end downwards and the pointed end upwards. Space the cloves 15cm (6in) apart, with the tip 2.5cm (1in) below the soil surface. In light soil, deeper planting can produce larger bulbs, but don’t plant deeply in heavy soil. Space rows 30cm (1ft) apart.
Birds will often pull up newly planted cloves, so cover with horticultural fleece until well rooted in.
Planting in modules
If your soil is heavy and/or wet over winter, start garlic off in modules in autumn, keeping them in a cold frame or unheated greenhouse over winter, then plant them out in spring.
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Partly fill a modular tray with peat-free multi-purpose or soil-based compost
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Insert one clove into each module and cover with more compost
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Place in a cool location protected from excess rain and the harshest winter weather – a well-ventilated cold frame is ideal
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Keep the compost moist but not wet
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Plant out in spring, into prepared ground (see above), 15cm (6in) apart
Plant Care
Garlic needs little maintenance, apart from watering in dry spells and weeding to prevent overcrowding. Also snip off any flower stems that start to form.
Watering
To improve bulb size, water garlic during dry spells in spring and early summer. However, don’t water once the bulbs are large and well formed, as this could encourage rotting – yellowing foliage is a sign that the bulbs are reaching this stage of maturity. Try to avoid overhead watering, as it can encourage fungal problems.
Weeding
Garlic needs full sun, so weed regularly to ensure plants don’t get shaded. This is best done by hand, as hoeing risks damaging the developing bulbs. Alternatively, to reduce the need for weeding, consider planting through weed-suppressing membrane or lay a mulch, such as cardboard, between rows.
Removing flowers
Remove any flower stems as soon as they start to form, otherwise the plant’s energy will go into producing the flower (bolting) rather than swelling the bulb. It also means the bulb won’t store well.
If picked young, while still in bud, these ‘scapes’ are delicious sautéed, barbecued or roasted.
Harvesting
Harvest garlic as soon as the leaves have turned yellow
Garlic bulbs are ready to harvest once the leaves have turned yellow. Autumn-planted garlic is ready in early summer and spring-planted from mid-summer to early autumn. Try not to delay harvesting, as the bulbs open up and store less well if lifted late. Carefully dig up the bulbs with a fork. Handle them gently, as bruising also reduces their storage potential.
Garlic can be used fresh, or dried and stored for several months.
Storing
To prepare garlic bulbs for storing, dry them off thoroughly in a single layer in the sun, ideally under a cloche or in a greenhouse. Ventilate well and avoid excessive heat (above 30°C/86°F). Alternatively, place them in a dry, well-ventilated shed.
Drying takes two to four weeks, depending on the weather. If you spot any mould, you can speed up the process using a fan heater, but this is not usually necessary. Once the foliage is dry and rustling, cut it off and store the bulbs in a cool, dry place at 5–10°C (41–50°F), where further drying will take place.
Garlic can usually be stored for several months. Softneck varieties store for longer than hardnecks.
Problems
Garlic is usually trouble-free in good growing conditions. However, it can potentially be affected by similar problems to onions and leeks (see Common problems, below). The following issues, related to growing conditions or harvesting, could also arise:
- Cloves forming on the stem – this is usually due to adverse weather, such as fluctuating temperatures in spring. Called top sets, the cloves can be used in the normal way
- Flowering (bolting) – hardneck garlic readily produces flower stems, which should be removed as soon as they appear and can be used in stir-fries. Softneck garlic occasionally produces flower stems due to poor growing conditions, such as high temperatures or drought
- Split bulbs – the crop was harvested late
- Green cloves – usually due to shallow planting or late harvesting. They can be used as normal, but are unlikely to store well
Get involved
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