Garlic 'Allium sativum' is a perennial crop and is grown by methods similar to those used in growing onions.

Fully-grown plants can reach about 50 to 60 cm (about 2 feet) in height and bears underground bulbous root containing about 8-20 bulblets known as cloves.

The whole bulb is encased by several layers of white or mauve-tinged thin papery coverings.

Several cultivar varieties exist from extra-large elephant garlic to small sized solo garlic. You can try Korean, Persian, Russian and Silician to name a few. Italian is one of my favourites, being mild but very flavourful, and Korean, which is medium flavour and large bulbs.

Field garlic or 'Allium oleraceum' is a wild, tall variety commonly grown in the United Kingdom. Unlike an onion, garlic flowers are sterile and therefore do not produce seeds. New plants generally are grown from implanting the individual sections of the bulb.

Here is a great article from Canadian Gardening on How to grow and harvest Garlic...

Growing garlic
With its heart-healthy benefits and powerful flavour, garlic more than deserves its place in your plot -

It's a mystery to me why there isn't more Canadian-grown garlic. A close relative of onions, leeks and shallots, garlic is no harder to cultivate. Thriving across the land in any moderately fertile, well-drained soil, garlic rewards the careful gardener with plump bulbs from midsummer well into winter.

Although it's a perennial bulb, garlic is grown as a hardy annual—hardy because the cloves are planted in the fall and must survive the winter; annual because it is harvested during its first year of growth.

There are three secrets to growing garlic: the first two — planting and picking — have to do with timing; the third is all about careful drying.

Unlike other vegetables, garlic (Allium sativum) goes into the ground in late summer or early fall, any time from mid-September to mid-October. When you order garlic to plant, you receive full intact bulbs, no different from the garlic that sits on your kitchen counter for cooking.

You then split the bulbs into individual cloves for planting; each clove you plant can yield a full bulb— or head— the following summer. Unless they are tiny, size is of little consequence; as you separate cloves, try to keep the protective papery husk around each one.

Planting tips Garlic is best planted in full sun, in a bed about a metre wide. The soil should be well drained, and dug to a depth of at least 20 centimetres, then raked to a smooth, level surface.

Draw out furrows of about four to six centimetres deep across the bed with the corner of a hoe. Leave 20 centimetres between the rows. Push single cloves into the furrows, about 15 centimetres apart, until the tips are barely visible, then draw in the ridges of soil from the furrows over the planted cloves to a depth of five centimetres.

Planted early, garlic may show a few points of green growth the same fall. In regions where snow cover comes and goes, mulch the garlic bed just before the first hard freeze. A layer of dry leaves (10 centimetres) is enough to keep the earth from freezing and thawing repeatedly.

Very early the following spring, garlic's broad blue-green leaves begin to grow solidly and by the end of May will reach a surprising height. (One visitor, looking at our garlic patch in May, wondered how we'd managed to get the "corn" so far along.)

Insects aren't interested in garlic plants, and spring rains are often enough to see them through to maturity.

A double yield: Garlic scapes in June

In mid-June, curly green pigtails emerge from the centre of each plant. These are the scapes, hard stalks topped with tiny bulbils.

All experts agree that it's best to nip garlic in the bud, as it were, snapping off the scapes after they have made a loop or two, to send more energy to the developing bulbs.

The scapes' tender tops (as opposed to the hard fibrous bottom portion) are loaded with flavour.

Peel and thinly slice them and add to a pesto, stew or frittata.

Havesting bulbs

Careless harvesting can ruin a fine crop of garlic, however, and timing is all-important.
Left in the ground, the bulbs grow overly large, and can split their papery casing. Garlic is harvest-ready usually sometime in July or early August, when the lowest three or four leaves have died back; that is, when the plant is about half green, and the rest is withered and brown.

Loosen the earth with a trowel or spade to release the plants.

Storing garlic

Careful drying means good long-term storage. An hour or two in the sun does no harm, but after that lay the bulbs (tops and all) in a single layer — a propped-up window screen works well here — in a dry, shaded spot, such as an airy garden shed, carport or barn;

It's best if the bulbs don't get wet.
In 10 to 14 days, they should be completely dry. Then, using secateurs, trim tops back a few centimetres from the bulbs, and gently rub the bulbs to remove dirt and loose skin.

Store the bulbs at room temperature or lower, somewhere not too humid (and not in the fridge).

Homegrown garlic is good stuff, miles away from pallid imports, and you'll be reaching for it often — for both flavour and health.

This article was available from: Growing Garlic By Patrick Lima, for Canadian Gardening