Garlic is a relatively easy crop to grow in most kitchen gardens and is an excellent companion to regular summer crops. In Europe, garlic is planted either between October and December for an early summer crop the following year, or between January and March for a late summer crop. Garlic, onions and leeks are ideal crops for extending the normal summer crop range.
Garlic (Allium sativum L.) is a member of the onion family and a close relative of the onion, shallot, leek and chive. It is a native of central Asia and has long been a staple in the Mediterranean region, Asia, Africa, and Europe. There are over 600 sub-varieties of cultivated garlic in the world. Most of the garlic consumed in Europe comes from Spain, Italy, France, Argentina and Iran. However, garlic will grow in Europe from the Mediterranean to the north of Scotland.
Everyone knows garlic is good for you but did you know it is considered a unique health supplement for its high content of minerals and vitamins such as potassium, calcium, selenium, manganese and zinc. Selenium particularly is beneficial for the heart and for the production of antioxidants in the blood while the allicin in garlic has been shown to reduce cholesterol. The anti bacterial, fungal, and viral properties in garlic prevent colds and infections while garlic’s sulphuric compounds lower blood pressure and boost immunity.
Garlic has both natural fungicidal and pesticidal properties that make it an ideal component for developing an integrated pest management strategy in the garden. The principal biologically active compound produced by garlic is allicin which has powerful antioxidant properties developed by the plant to deter pests. The growing plant and root have this repellant action against a number of garden pests and soil born infections. Garlic based plant sprays are a well known organic method for dealing with tomato blight, aphids and caterpillars, slugs and snails.
There are basically two main types of garlic, hardneck and softneck:
Hardneck garlic has a stiff central stem or neck which curls at the top forming a 360° coil. It produces fewer cloves around the woody stem in a single ring which are larger and easy to peel and have a deeper stronger flavour than softneck varieties.
Hardneck varieties produce “scapes” in the early stages of growth which are similar in taste to spring onions. Removing these in early growth has been shown to increase bulb size at maturity. The scapes can be eaten raw or cooked.
Softneck garlic has layers of up to 20 cloves around a stem which is soft and pliable at maturity and used for braiding the garlic bulbs together. It has a milder flavour and keeps well once lifted. Softneck varieties are easy to grow, particularly in cooler climates.
The latitude where garlic is grown ultimately determines the choice of type as garlic is photoperiodic or day-length sensitive. Hardneck garlic is generally grown in cooler climates; softneck garlic is generally grown closer to the equator.
Elephant garlic is a completely different kind of garlic and grows huge bulbs. It is not a true garlic but a type of leek. This plant gets its name for its size; it has large fist-size bulbs weighing up to ½ pound or more. Elephant garlic has a mild flavour.
When to plant
Garlic is easy to grow and will grow year-round in mild climates. However, garlic is a crop that benefits from a period of cold which encourages growth beneath the soil in preparation for full growth when the weather warms. For best results (reasonable sized bulbs) the main crop is planted in the autumn (October to December). Ideally, the plants require a period of 0 – 10°C for 1 – 2 months in order for the plants to bulb properly for a harvest in 8 months.
That said, many varieties of garlic are suited to an early pre-spring planting (January to March) for harvesting in the late summer or autumn. With the weather generally still cold enough during these months the bulb development can occur sufficiently for the plant to fully mature when the warmer weather begins.
Traditionally in northern Europe, the main garlic crop was planted on the shortest day (December 21) and harvested on the longest (June 21). However, with the shifts in regular weather patterns, unseasonable winter weather and false spring weather, garlic can be considered suitable for planting in two stages, autumn and pre-spring.
In general terms, garlic prefers cool weather when developing foliage and warm weather when bulbs enlarge. It is this combination of cold weather treatment and then warm weather growth that is the key to successful garlic production.
Garlic can be planted into pots in the autumn and stored over winter ready for planting out into beds in the spring.
Where to plant
Garlic is ideal for the city garden because a lot of garlic can be planted in a small space. It grows well in reasonable sized containers or in raised beds. It does not do so well in heavy soils or damp ground which is the main issue facing gardeners in Belgium where summers can be wet.
Garlic requires a well-balanced and free draining soil that is fairly loose so the bulbs can expand properly, such as a raised bed. Clay and heavy soils, especially after rain, can pack tightly around the cloves and prevent them from reaching their full size. Raised beds are particularly important for growing garlic in areas with wet conditions as they drain better.
Garlic requires well fed soil, preferably loaded with well rotted compost some time before planting.
Garlic will grow well in larger pots and containers that have good drainage. In gardens that are prone to damp, containers are the safest way to ensure the bulbs do not sit in wet conditions and spoil. As garlic has fairly shallow roots it is important to make sure they have plenty of room to stretch out in the soil. Choose a pot that is at least 18 inches deep and 12 inches wide for best results.
Garlic can be grown in pots indoors but are unlikely to produce bulbs. The garlic shoots produced are good for cooking or use in salads. Simply plant a few cloves in a pot, sit in a sunny position, water lightly and shoots appear within a week or so.
How to plant
A bulb of good garlic is basically carefully broken into its individual cloves and planted within 24 hours to prevent the individual cloves from drying out. The individual cloves are left wrapped in their covering paper layer. It is important to source good quality garlic bulbs as generally garlic from shops or supermarkets is unsuitable for replanting. Using the largest cloves from a bulb is best, taking the smaller ones for cooking.
Garlic can be planted quite close together allowing space for the finished bulb to develop (about 4-6 inches apart). Individual cloves are planted about one inch under the soil in spring, two inches in autumn (to protect from frost). Garlic cloves have a blunt end and a sharp end and are planted with the sharp end pointing up.
In a soil bed, garlic is planted by scraping a small trench about two inches deep and placing the cloves (right way up) every 4-6 inches. The soil is then backfilled over the row and the soil firmed down. This is called furrow planting.
For heavy soils or in conditions with heavy rain it is worth planting the cloves on the surface and “hilling up” the soil over the clove to a height of about two inches. Do not plant garlic in poorly draining soil as garlic cloves can rot if they sit in water or mud.
Planting garlic in pots or containers is quite straightforward. Individual cloves can be planted in single pots, 6 inch wide by 6 inch deep, or several cloves into larger pots. Cloves are planted about 1 inch under the soil. In larger containers rows of cloves can be furrow planted.
When to water
Once planted, garlic requires little watering, especially when grown in areas prone to rain and wet soils. However, during dry spells in spring and summer water thoroughly every 14 days. To reduce the risk of fungal diseases water the ground and not the foliage. Stop watering when the foliage begins to yellow in summer.
As garlic is prone to disease in damp conditions it is important not to over water. In this respect, garlic works better in raised beds with good drainage or in containers (also with good drainage) as opposed to open soil beds with heavy soils where damp conditions can persist.
Watering is stopped altogether in the weeks before harvest as this helps concentrate a last growing spurt in the garlic bulbs.
When to harvest
Garlic requires a long growing season, up to 8 months for optimal yield. Spring sown varieties can produce in 6 months. Thus garlic planted in the autumn should be ready for harvesting around June, and garlic planted in early spring, around October. This is not an exact science so observation of the growing plants within the seasonal conditions is necessary.
The first stage in harvesting garlic is in early spring when plants are about 12 inches tall. The green leaves can be cut (not completely) and used fresh or cooked and some whole plants can be pulled and used much like garlicky spring onions.
A second harvest occurs mid summer when hardneck varieties produce scapes. These scapes are the flower stalks of the plant which, if left on the plant will open up into flowers. The scapes are removed to prevent the plant’s growing energy going into the flower and not the bulb. These also can be eaten raw or cooked.
The main harvest is when the underground bulbs are dug up. When exactly to lift the bulbs is a tricky matter as lifting them too soon results in immature bulbs and too late results in the cloves separating from the bulbs. The trick here is watching the leaves start to die back, digging up the bulbs when the bottom leaves are dead and while the top leaves are still green. About one third of the leaves should be yellowed and dead.
In this respect, for first time garlic growers, it is worth organising planting so plants are well enough spaced that one bulb can be dug up without disturbing neighbouring plants. A good mature bulb should be fully swelled with the paper like wrapping showing slight signs of decomposition.
Removing bulbs from the ground is done carefully, preferably when the soil has been dry for over a week, with a spade or fork working under the bulb, loosening the soil around it. Avoid slicing into the bulbs.
After lifting, do not wash off the bulbs as any dampness can cause the bulbs to spoil. The bulbs are now ready for curing or air drying which is done by hanging the bulbs (softnecks braided) or storing them in a cool dry place away from sunlight for several weeks. The bulbs are considered cured once the wrappers are dry and papery like those bought in stores.
Select the best of the bulbs for use in the next planting and in this way start developing your own localised strains of garlic for your garden.
What to watch for
Garlic is prone to a number of diseases mainly associated with damp soil conditions. In soil beds these are difficult to deal with while in raised beds or containers they are not so prevalent. In this respect first time garlic growers may spend a year exploring how the garlic performs in different areas of the garden, identifying the best spots for following years.
The main diseases affecting garlic are rust and white rot. Rust appears as rusty coloured spots on the leaves while white rot decays the roots and the bulb. There is no cure for these conditions and basically the plants should be removed and binned (not composted). If these diseases occur garlic should not be regrown in these spots in the garden.
Wet conditions are the main cause of garlic growing problems so for European gardeners, a pleasant dry summer is wished for.
Garlic is an excellent companion plant to many of the regular summer vegetables (tomatoes, cucumbers, peppers) helping to protect them from pests and disease. Slugs and snails avoid garlic so for gardeners plagued with these it is worth attempting to create an under-story of garlic among plants and several areas of barrier planting to discourage these pests.
Home made garlic spray has been used by organic growers for many years to treat a range of problems in the garden. A basic spray involves 1 clove of garlic crushed with 1 medium sized onion, one teaspoon of cayenne pepper and one tablespoon of washing up liquid mixed in water. Filter the results and use in a simple spray bottle.
This spray has been shown to help treat early blight in tomatoes, and effectively deter insects and pests from salad crops and other vegetables without leaving any after taste on the crops. Research work at Newcastle University has also found that a recipe of crushed garlic cloves mixed with water kills slug eggs laid in the soil. This is an important new development for organic gardeners looking for non-chemical pesticides.
Ready to use garlic sprays also exist.
Growing garlic is not an obvious choice for the damp and wet conditions of your average European city garden. However, with some care, garlic can be quite successful in raised beds and containers, producing a good crop in late spring and late summer. Beyond this, for gardens bothered by snails and slugs, garlic is a natural deterrent of some considerable value.
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A family business who have been growing garlic on the Isle of Wight for over 50 years. They specialise in all things garlic and have a particular expertise in varieties suitable for northern Europe.