Garlic goes into the ground as individual cloves, not as whole bulbs. Once planted, each sound clove has the potential to grow into a new bulb. The method is straightforward, but the position, season and orientation of the clove all matter. Garlic dislikes wet, compacted ground, and many varieties need a spell of cold weather to form well-developed bulbs.
For a UK garden, autumn planting is common. It allows roots to establish before spring growth begins. Some cultivars are suitable for planting in late winter or early spring, so check what the supplier says rather than assuming supermarket garlic will behave like planting stock.
Buy garlic intended for planting
Look for named seed garlic from a gardening supplier. A bulb at the supermarket is intended for eating; it may have been stored or treated in ways that affect growing, and you may not know what cultivar you are buying.
There are two broad types. Softneck garlic is often suited to storage and can produce plenty of cloves. Hardneck types make a stiff flower stalk, called a scape, and some are particularly well suited to colder conditions. Within each type there are differences in growing season and keeping quality.
Pick firm, healthy bulbs without mould, damp patches or shrivelled cloves. Break a bulb apart shortly before planting, keeping the papery skins around the cloves. You don't need to peel each clove as though preparing it for the saucepan.
Decide when to plant
Most garlic is planted from mid-autumn to early winter. According to the RHS, many varieties benefit from one to two months at approximately 0–10°C, which helps normal bulb formation. That is one reason an autumn start can work well in Britain.
Spring planting isn't automatically a failure. It is better to choose a variety sold specifically for that purpose and plant as soon as the soil is workable. Later planting generally leaves less time for a big bulb to develop.
Avoid forcing cloves into frozen or waterlogged soil. In a particularly wet winter garden, start them in modules in a sheltered cold frame and transplant them into prepared ground in spring. They still need cool conditions; a hot living-room windowsill is not the ideal substitute.
Choose a sunny bed that drains properly
Garlic benefits from a sunny, open position where rain can drain away. Remove perennial weeds before planting because they are difficult to pull out once garlic roots spread through the bed.
If your soil is heavy clay that stays wet, a raised bed or large container may be easier to manage than an unimproved patch of ground. Organic matter can improve structure when incorporated appropriately, but don't leave an undrained basin beneath a shallow layer of loose compost.
A bed previously used for onions or leeks may harbour pests or diseases affecting the same plant family. Rotate crops where possible. Keep the soil reasonably level so cloves can be planted at a consistent depth.
Split the bulb and face each clove upwards
Separate the bulb into cloves just before planting. Reserve the plump, undamaged cloves for the main crop; very tiny ones may produce smaller bulbs. Discard cloves showing mould or soft spots.
Find the broad, flattened base on each clove. This is the root end and must face downwards. The pointed end faces upwards. If a clove is planted sideways, it may still grow, but correct orientation gives its new shoot the easiest route to the surface.
Press or place the clove into prepared soil without crushing it. The RHS advises planting with the pointed tip roughly 2.5cm below the soil surface, around 15cm between cloves and 30cm between rows. Soil type matters: particularly heavy ground is a poor place for deep planting.
Water and protect your newly planted bed
Water after planting if the ground is dry. In a wet autumn, additional watering may be unnecessary. Garlic wants moisture to grow roots, but saturated soil invites rot.
Birds sometimes pull up freshly planted cloves or the new green shoots. Use a securely fastened, wildlife-safe horticultural fleece or suitable mesh until the roots are firmly established. Check protection regularly rather than leaving loose netting where birds or small animals could become caught.
Label the row with the cultivar and planting date. It is surprisingly easy to forget whether a young green shoot belongs to garlic, an onion set or a volunteer plant when several beds are being used.
Planting garlic in a pot
Choose a container at least about 25cm deep with good drainage holes. Its width determines how many cloves fit while keeping the same spacing you would use in the ground. A cramped bowl cannot support a whole row just because the cloves fit under the compost.
Fill it with suitable peat-free multipurpose compost and position it in an open, sunny spot. Do not leave the pot sitting in a saucer of rainwater throughout winter. A raised pot on feet can help excess water drain away.
Container compost dries out more quickly during spring growth than garden soil. Check moisture with your finger, especially in dry winds, but let the pot drain freely. Crowding and erratic watering are more likely to limit your crop than a shortage of specialised fertiliser.
What garlic does over winter
Cloves often send out shoots before spring, and that is normal. A short green tuft can survive cold weather. Some foliage may look battered after a severe frost; don't dig everything up to see whether it is still alive.
Roots are developing below ground long before you see vigorous top growth. Keep weeds down and remove any winter debris that smothers the shoots. Avoid repeatedly hoeing deep around plants, which can damage shallow roots.
If bulbs were planted in modules, wait until the ground is workable and the young plants are sturdy before transplanting them. Handle each rootball intact, set plants at their correct depth and water them in.
Care through spring and early summer
As days lengthen, the leaves should grow strongly. During dry spells, water enough to support steady growth, particularly in pots. Do not keep watering heavily when the crop is approaching maturity and the foliage is naturally beginning to yellow.
Hardneck garlic may produce a curling flower stem or scape. Many gardeners remove scapes while young, which can direct resources towards the bulb; the tender scapes are also edible when sound and prepared appropriately.
Keep watching for rust-coloured pustules on leaves, yellowing unrelated to maturity, or plants collapsing in wet soil. Healthy green growth and a slowly swelling base are better signs than guessing from the number of leaves alone.
Know when your crop is ready
Garlic is usually harvested in summer when leaves begin to yellow and die back, but timing varies with planting date, weather and variety. Avoid waiting until every leaf has disappeared: bulbs can split their protective skins if left too long.
Loosen the earth with a fork set away from the bulb and lift carefully. Don't tug hard at the stem, which can snap. Handle bulbs gently; bruises reduce their keeping quality.
Dry the harvest in an airy, sheltered, rain-free place. Once cured, store sound bulbs somewhere cool, dry and ventilated. Do not put wet, freshly dug garlic straight into an airtight plastic bag.
Fixing the most common failures
Small bulbs can result from late planting, insufficient light, crowded cloves or poor growing conditions. They are not proof that you planted upside down. Check the cultivar's needs and your spacing before changing everything next year.
A clove that rots without sprouting often points to waterlogged soil or poor planting material. Improve drainage rather than watering more heavily. If shoots have been pulled from the soil, consider bird protection.
Some cloves may form a single round bulb instead of separating into distinct cloves. That can happen when conditions don't provide enough development time or cold. Keep records and select varieties suited to your climate next season.