Growing Garlic in Scotland: The Complete Guide

Allium sativum

Everything you need to grow garlic in Scotland, from cloves pushed into autumn soil to bulbs drying in the July sun. We have done the research so you don't have to.

Garlic wants a cold winter. It is one of the few crops on this site where that sentence is a statement of fact rather than a problem to solve. Most varieties need one to two months below 10°C to form bulbs properly, a process called vernalisation. A Scottish winter delivers that cold as reliably as rain, and a milder southern winter that falls short leaves the cloves undivided and the bulb poor. What other growers chase with variety choice and timing, we get from the climate itself.

Hardneck or softneck

The single most useful decision on this page is not which variety to buy. It is which type, because the two are different enough to change what you harvest and how long it lasts.

• Hardneck garlic produces bulbs with fewer, larger cloves and a stronger, more complex flavour. It stores for about four to six months. It is more prone to bolting, sending up a curly green flower stem in late spring. Cut that stem off as soon as it appears, because the energy it would use to flower is energy the bulb does not get. Picked young, while still in bud, the scape is tender and worth cooking with.
• Softneck garlic has smaller cloves packed in more layers, a milder flavour, and a far longer storage life. An autumn-planted softneck keeps through to the following winter. Softneck is also less likely to bolt. It only does so in poor growing conditions like drought or high temperatures, which in most Scottish summers are rare.

For flavour, grow hardneck. For a crop that sees you through winter into spring, grow softneck. A row of each costs little more than one row of either and gives you the best of both.

Varieties

Every variety below carries the RHS Award of Garden Merit, a UK-wide award, not a Scottish one, since nobody trials garlic for Scottish gardens. The hardneck-or-softneck choice above matters more than which named variety you pick.

Also worth considering

The softneck AGM varieties are the practical choice for a Scottish kitchen. A bulb that is still sound in January has earned its space in the ground, and the storage difference between hardneck and softneck is the single biggest factor in whether you actually use what you grow. That said, do grow some hardneck too. The flavour is worth it, and the scapes are a bonus crop that cost nothing.

Soil and site

Garlic wants an open, sunny position and free-draining soil. This is the requirement that decides whether your crop survives the winter. If water sits on the bed through the wet months, the cloves will rot rather than root. On heavy ground, start the cloves in modules in autumn and plant them out in spring, or grow in containers.

Garlic dislikes acid soil below pH 6.5. This matters in Scotland because our soils are naturally acidic and plenty of gardens sit below that mark. Teagasc allium guidance puts the growth restriction at 5.8. Below that, the crop struggles. A cheap soil test before planting tells you in minutes whether you need to lime, and if you do, apply it in autumn or winter a few weeks before the cloves go in.

Dig in about two bucketfuls of well-rotted compost or manure per square metre before planting. Do not use fresh manure. Weed the bed thoroughly. Garlic cannot shade out competition, and every weed that germinates will take light and water the cloves need.

Planting

Plant cloves from mid-autumn to early winter. The exact month matters less than getting them in before the ground freezes. Break the bulb into individual cloves just before planting, not days in advance, because the cloves dry out.

Push each clove into the soil pointed end up, about 2.5cm deep, so the tip sits just below the surface. In light soil you can go a little deeper, which tends to produce larger bulbs. On heavy soil keep it shallow. Space them 15cm apart with rows about 30cm apart. Planted upside down, a clove will still try to grow but it wastes energy sorting itself out and the bulb will be smaller.

Birds sometimes pull newly planted cloves out of the ground. Protect with netting or fleece until the cloves have rooted in.

On heavy or wet soil: start cloves in modules in autumn instead. Fill a modular tray with compost, insert one clove per module so the tip is covered by about 2.5cm, and keep them in an unheated greenhouse or cold frame over winter. The compost should stay slightly moist, never wet. Plant out in spring at the same spacing.

In containers: garlic grows well in pots. Use a container at least 25cm deep, filled with peat-free multipurpose compost. Space the cloves as you would in the ground. Compost in pots dries out faster than soil, so check regularly in spring.

Watering and weeding

Garlic needs watering during dry spells in spring and early summer. That is when the bulbs are swelling and the crop is made. Stop watering once the leaves start to yellow, because wet bulbs at that stage encourage rot. Water the soil, not the leaves, to reduce the risk of fungal problems. In a typical Scottish spring you may not need to water at all, but a dry spell during bulb fill is worth reaching for the watering can.

Weeding is the job that makes the difference. Garlic cannot shade out competition and its thin upright leaves cast almost no cover. Hand-weed close to the plants. A hoe risks damaging the developing bulbs just below the surface. A clean bed through spring is the sign of bulbs worth lifting.

White rot, the one that stays

White rot is the serious allium disease, and it is the reason rotation matters. The first sign is yellowing leaves that wilt and die back. Lift the plant and you will find a white fluffy fungus at the base with tiny black dots. There is no treatment.

The defence is prevention. Keep garlic, onions, leeks and shallots off the same ground for four to five years. Never accept allium plants or soil from other gardens. Do not move tools or soil from a bed where you have seen it to a clean one. If you have never seen white rot in your garden, the most useful thing you can do is keep it that way.

Harvesting and storing

Autumn-planted garlic is ready from late spring to early summer. Spring-planted from mid-summer to early autumn. The signal is the leaves: once they turn yellow, lift the bulbs carefully with a fork. Do not delay. Bulbs lifted late split open and their storage life shortens sharply. Handle gently, because bruising also cuts into how long they will keep.

Dry the bulbs in a single layer in the sun for two to four weeks. A well-ventilated greenhouse is ideal, but keep the temperature below about 30°C. In wet weather, use a dry, well-ventilated shed instead. Once the foliage is papery and rustling, cut it off and store the bulbs somewhere cool and dry, ideally at 5 to 10°C.

Hardneck garlic keeps for about four to six months. Softneck keeps far longer. An autumn-planted softneck will still be good the following winter, which in a Scottish kitchen is doing real work. Check through the bulbs every few weeks and use any that are softening. Keep the biggest, healthiest bulbs back for next year's planting stock.

Common problems

• Cloves rotting over winter. The soil is too wet or too heavy. Plant on a slight ridge, choose the best-drained spot you have, or start in modules.
• Onion white rot. White fluffy fungus at the base, no treatment, rotation is the only defence.
• Rust. Bright orange raised spots on the leaves. The fungus spreads most readily at 10 to 18°C, with August to October the worst months. Frost knocks it back, and it is not soil-borne. It survives only on living green tissue. Good spacing and airflow reduce the risk. It is usually disfiguring rather than fatal, and the bulbs are still fine to use.
• Bulbs not dividing into cloves. The winter was too mild and the cloves did not get enough cold. A single round bulb is perfectly edible, or you can replant it the following autumn and it will usually divide.
• Split bulbs. You harvested too late. Lift as soon as the leaves yellow.
• Green cloves. The cloves were planted too shallow. They are fine to eat but will not store well.
• Top sets. Small cloves forming on the stem instead of in the ground. Usually caused by changeable spring weather. Use them as you would normal garlic cloves.

Common questions

Sources