Garlic

Light and exposure

Garlic wants full sun, no compromise. Give it the most open and sunny bed in the garden, away from tall vegetables that would cast shade. The less light it gets, the smaller the heads stay.

Avoid the low corners of the garden where water sits and air circulates poorly after rain. A spot on a slight slope, or a raised, well-aired bed, always gives better results than a damp bottom of the garden.

Watering

This is one of the most frugal crops in the vegetable garden. Once the cloves are in place in autumn, the rainfall of the cold season is more than enough under a temperate climate, and most years you will have nothing to water until growth picks up strongly at the end of winter. Too much water does far more damage than too little.

Only water in the event of a real prolonged drought in spring, when the foliage is growing strongly. As soon as the leaves start to yellow, near harvest, stop all watering: the heads finish ripening in dry conditions, and waterlogged soil at this stage makes them rot in the ground.

Soil and repotting

Drainage is the point that decides everything. Garlic demands a light, loose and above all well-drained soil; it hates heavy, waterlogged ground, where it rots before bulking up. In clay soil, plant on a small ridge ten to fifteen centimetres high so the water drains away and the cloves never sit in water.

When planting, push each clove point up, five centimetres deep, spaced ten to fifteen centimetres apart, in rows thirty centimetres apart. Never add fresh manure: it makes garlic rot and encourages disease. Simply loosened soil, with no fresh manure, suits it very well.

Temperature and humidity

Garlic is perfectly hardy and overwinters outdoors without protection under a temperate climate. Cold is not an enemy, quite the opposite: white and purple garlic need a period of winter cold, vernalisation, to divide properly and form a head with several cloves. Without that cold spell, you often harvest a single bulb, with no cloves.

The real danger is not the temperature, it is the moisture in the soil during the cold months. Heavy soil that stays waterlogged all winter makes the cloves rot before they even get going. The ridge in clay soil and full sun are your best insurance against this risk.

Pruning and upkeep

There is no pruning as such, but one useful task on autumn garlic. In spring, some varieties send up a rigid flower stalk in the centre, the scape. Cut it as soon as it appears: the plant stops feeding the flower and concentrates its energy in the head, which bulks up all the more. These scapes, tender, are actually very good to cook.

Weed regularly around the plants, as garlic tolerates competition from weeds poorly. A light hoeing now and then keeps the soil aerated. Watch the foliage in spring: it is what will warn you of the first signs of disease.

Pests and diseases

Garlic rust is the most common enemy under a mild, damp spring. You spot it by small, bright orange pustules that speckle the leaves. It weakens the plant and reduces head size. You limit it by spacing the plants well so air circulates, avoiding any excess nitrogen and never wetting the foliage.

White rot, a soil fungus, is more serious because it persists in the ground for years. It makes the plants yellow then rot, with a white felting at the base. The only real defence is a long rotation: never replant garlic, onion or leek in the same spot for four to five years. In soil that is too wet, clove rot is also a threat, hence the importance of drainage.

Propagation

Garlic is propagated only by its cloves, there is no sowing. Take a healthy head, detach the cloves one by one just before planting, and keep the largest ones from the outside: those are the ones that will give the finest heads. Each clove planted becomes a whole head.

Always use healthy seed cloves, bought at a garden centre or saved from your own harvest. Avoid supermarket garlic: it is often treated so it won’t sprout, sometimes carries disease, and is poorly suited to your climate. A locally grown seed garlic, replanted year after year from your finest heads, adapts and improves.

Toxicity

Harmless to humans, it is an everyday seasoning. Garlic, however, is toxic to dogs and cats: it destroys their red blood cells and can cause anaemia. Don’t leave peelings or heads within their reach, and never slip any into their bowl.

Month-by-month care calendar

Green Hub tips

• Plant white and purple garlic in autumn, never in spring: without winter cold, it won’t form true heads with several cloves.
• In clayey, damp soil, always plant on a ridge ten to fifteen centimetres high. Garlic rots as soon as it sits in water, and that is the number one risk under a mild, rainy winter.
• Stop all watering as soon as the foliage yellows, close to harvest. The heads finish ripening in the dry; waterlogged soil would make them rot.
• Never replant garlic in the same spot for four to five years, nor onion or leek: white rot settles into the soil for years.