Garlic is an annual bulbous herbaceous plant in the family Amaryllidaceae, which is grown for its pungent, edible bulb.
The plant can either have a short, woody central stem (hard neck) or a softer pseudo stem made up of overlapping leaf sheaths (soft neck).
Hard neck varieties produce a false flower stock which is known as a scape and produce larger garlic cloves but in smaller numbers while soft neck garlic produces relatively smaller cloves and has a stem which is very short and flattened and gives way to a pseudo stem.
The garlic plant can have 6–12 flat, blade-like leaves which can stretch up to 50 cm long and it can reach 60 cm in height.
Garlic is majorly used for flavoring food and can be dried, ground or powdered for this purpose.
Garlic is a hardy perennial which can be grown in a variety of soil types.
The plant performs best in a light, well-draining, organic soil with an optimum pH of between 6-7. It grows well in cool weather but can tolerate a temperature range of from 9–28 degrees centigrade. Garlic should be planted in an area that receives full sun for most of the day because it requires a period of cold followed by a period of light and heat in order to develop properly.
Planting & Cultural Practices
Most garlic varieties do not produce fertile seed and therefore, the plant is mostly propagated from the cloves. The individual cloves are obtained by breaking apart the bulb.
Cloves should be planted 5–8 cm deep, leaving 8–10 cm between individual plants and 15–20 cm between rows. They should be planted with the pointed side up and the basal plate positioned downwards.
Roots grow from the basal plate.
Each clove produces a whole head of garlic.
Irrigation– the plant requires additional irrigation during dry periods but watering should be ceased a few weeks prior to harvesting, in order to allow the papery skin around the bulb to dry and to prevent the development of disease.
Pruning– the hard neck garlic should be pruned when the flowering stalks/scapes begin to straighten. Removal of the flower head directs the plant’s energy to bulb production. Softneck garlic does not require pruning.
Weeding– weeds compete with the crop for growth factors and also harbour pathogens. Garlic is a poor competitor with weeds and therefore the garden should be kept weed free.
Mulching- this helps in retention of moisture and suppression of weeds. When the mulch decomposes, it releases nutrients into the soil which are absorbed by the plans.
Pests & Disease Control
Onion maggot– infestation causes stunting or wilting of seedlings and plants commonly break at soil line if an attempt is made to pull it up. If infestation occurs when plants are bulbing, bulbs become deformed and susceptible to storage rots after harvest.
Drench soil with PROFILE 440EC 60ml/20l or PENTAGON 50EC 20ml/20l
Thrips– these cause significant economic losses. They cut the epidermis of the leaves or stem and suck the plant sap creating white silvery patches on the deformed leaves.
Spray ALONZE 50EC 5ml/20l or PROFILE 440EC 30ml/20l or DEFENDER 25EC 40ml/20l
Nematodes– the common symptoms due to infestation include an erratic plant stand developing in the field, stunting of plants, yellowing, deformed bulbs, and stem swelling. Root system lacks fine roots and round or irregular lesions form on roots.
Drench soil with ALONZE 50EC 10ml/20l or mix fertilizer 50kg with ADVENTURE 0.5GR 2kg whenever doing basal application of fertilizer
Garlic mosaic virus (GarMV) – infection causes formation of mosaic patterns on leaves, chlorotic mottling or streaks on leaves, stunted plant growth and reduced bulb size. It is transmitted by aphids.
Control aphids with KINGCODE ELITE 50EC 10ml/20l or LEXUS 247SC 8ml/20l or PRESENTO 200SP 5g/20l
Damping off– these results in seed and seedling rot before they emerge out of the soil. The pathogen can also attack the collar region of seedlings on the surface of soil, which rots and ultimately the seedlings collapse and die.
Drench soil with PYRAMID 700WP 100g/20l
Spray CHANCETYL ELITE 800WDG 50g/20l or MILLIONAIRE 690WDG 40g/20l
Bacterial soft rot– this is mainly a problem on mature bulbs. Affected scales first appear water-soaked and pale yellow to light brown. As the disease progresses, invaded fleshy scales become soft and sticky with the interior of the bulb breaking-down. A watery, foul-smelling thick liquid can be squeezed from the neck of diseased bulbs.
Drench soil with GREENCOP 500WP 100g/20l or COLONIZER 440WP 100g/20l or TRINITY GOLD 425WP 100g/20l
Purple blotch-the symptoms occur on leaves and flower stalks as small, sunken, whitish flecks with purple coloured centres. These lesions may girdle leaves/stalk and cause their drooping. Infected plants fail to develop bulbs
Spray COLONIZER 440WP 50g/20l or ABSOLUTE 375SC 10ml/20l or TRINITY GOLD 425WP 50g/20l
Colletotrichum blight/anthracnose/twister disease– symptoms due to infection appear initially on the leaves as water soaked pale yellow spots, which spread lengthwise covering entire leaf blade. Affected leaves shrivel and droop down.
Spray RANSOM 600WP 15g/20l or DUCASSE 250EC 20ml/20l or PROVIDENCE 400WP 50g/20l
Fusarium basal rot/basal rot– Initially yellowing of leaves and stunted growth of plant is observed, which later on dry from tip downwards. In early stage of infection, the roots of the plants become pink in colour and rotting takes place later while in advanced stage, the bulb starts decaying from lower ends and ultimately whole plant dies.
Drench soil with PYRAMID 700WP 100g/20l or GEARLOCK TURBO 250WP 50g/20l
White Rot– the initial symptoms are yellowing and dieback of leaf tips. Later, scales, stem plate and roots get destroyed. The bulbs become soft and water soaked, and as infection progresses, white fluffy or cottony growth of mycelium with abundant black sclerotia resembling mustard grain develops on the infected bulbs.
Spray MILLIONAIRE 690WDG 40g/20l or RIMETA GOLD 300SC 40ml/20l or EXEMPO CURVE 250SC 15ml/20l
Downy Mildew-symptoms of this disease are quite distinct. A whitish, furry growth occurs on the leaves, along with yellow discoloration. Infection can kill younger plants and stunt the growth of older ones. Diseased leaf tips and other tissues eventually collapse. Bulbs in storage develop a blackened neck, become shriveled, and outer scales become water-soaked. Some bulbs may sprout prematurely.
Spray GEARLOCK TURBO 250WP 25g/20l or FORTRESS GOLD 720WP 40g/20l or TRINITY GOLD 425WP 50g/20l
Botrytis Rot– infection causes the stems to develop water-soaked and gray fuzzy fungal growth. This disease is also called “neckrot.”
Spray EXEMPO CURVE 250SC 15ml/20l or IPRODE 500SC 10ml/20l or EXPLORER 3SL 10ml/20l
Penicillium Decay– infection causes seed clove decay often resulting in stunted, wilted, and yellowing plants. Disease can also reduce growth. The fungus may sporulate on diseased cloves, appearing as a bluish-green mass.
Spray ABSOLUTE 375SC 10ml/20l or TRINITY GOLD 425WP 50g/20l
Black mould – infection usually is through neck tissues as foliage dies down at maturity. The infected bulbs become discolored black around the neck, and affected scales shrivel. Masses of powdery black spores develop as streaks along veins on and between outer dry scales. Infection may advance from the neck into the central fleshy scales.
Spray EXEMPO CURVE 250SC 15ml/20l or EXPLORER 3SL 10ml/20l or ABSOLUTE 375SC 10ml/20l
Maturity, Harvesting & Post-Harvest Handling
Garlic is ready for harvesting when the plants begin to turn yellow or brown and begin to fall over.
The bulbs are harvested by digging the plant carefully and lifting the bulbs using a fork. In large scale onion/potato lifters can be used to lift the bulbs. This should be done while there are still some green leaves remaining on the plant.
The harvested garlic can be used straight away or it can be cured for longer storage.
Curing garlic can be achieved by hanging the plants in bunches or by spreading them out on a rack or screen. The plants should be kept intact while they cure; the tops should not be removed until the garlic is dry. This should be carried out in a cool, dry place with good ventilation.
Once completely dry, the bulbs can store for up to a year.
Garlic is stored in net bags, crates, in pallet boxes, or in bulk bins. When stored in bins or boxes, there should be at least some vent space. Bags of garlic are usually stored on pallets and should be stacked to allow proper air circulation.