garlic has been a popular ingredient both as a spice and medicine since ancient times. Whether it is Asia, Europe or Australia, people eat garlic throughout the world for various reasons ranging from food to medical benefits. It contains different nutrients and nutritional matter that function as antibiotics in the body. In other words, it helps boost immunity.
Botanical name Allium sativum and Allium sativum var. ophioscorodon
Climate for garlic cultivation
Garlic cultivation needs a combination of different types of climate. It needs a cool and moist climate for bulb development and vegetative growth while for maturity the climate must be warm and dry. However, it cannot tolerate extreme cold or hot conditions. Exposing the young plants to temperatures lower than 20⁰C for 1 or 2 months would hasten the bulb formation. A prolonged exposure to lower temperature would however reduce the yield of the bulbs. Bulbs maybe produced at the axil of the leaves. A cooler growing period gives higher yield than warmer growth conditions. The optimal day length requirement for bulb formation is 13-14 hours for long day garlic and 10-12 hours for short day garlic.
Soil for garlic cultivation
Although garlic can grow in different types of soil, loamy soil with natural drainage is optimum for this crop. It grows at an altitude of 1200 to 2000 m above sea level. It is sensitive to acidic and alkaline soils, hence, a pH of 6-8 is suitable for optimal growth of garlic. A clayey, water-logging type soil is also not suitable for garlic growing. Soils with rich organic content, good moisture, high amount of nutrients aid in proper bulb formation. A heavy soil with less moisture and more water logging would result in deformed bulbs. Soils with poor drainage capacity causes discolored bulbs.
Varieties for garlic cultivation
There is no distinct variety of garlic. Local varieties are either white in colour and have fairly big bulbs with a better keeping quality and a higher yield or red in colour with pungency. Tamil Nadu Agricultural University has recently released one improved variety by clonal selection viz., Ooty 1 Garlic. It is a high yielder (17t/ha) with a shorter duration of 120 to 130 days. The bulbs are big sized weighing 20 to 30g and each bulb has 22 to 25 cloves, which are dull white in colour.
Propagation for garlic cultivation
Garlic is propagated by cloves. All the cloves are planted except the long slender once in the centre of the bulb. Bulbs with side growth should be discarded. Healthy cloves or bulbils free from disease and injuries should be used for sowing and about 150 to 200 kg cloves are required to plant one hectare. They are sown by dibbling or furrow planting.
Dibbling: The field is divided into small plots convenient for irrigation Cloves may be dibbled 5 to 7.5cm deep, keeping their growing ends upwards. They are laced 7.5cm apart from each other in rows of 15cm apart and then they are covered with loose soil. June-July and October-November are the normal planting seasons for garlic.
Furrow planting: The furrows are made 15 cm with hand how or a cotton drill. In these furrows, cloves are dropped by hand 7.5 to 10 cm apart. They are covered lightly with loose soil and a light irrigation is given.
Manures and fertilisers for garlic cultivation
About 25 tonnes of farm yard manure is applied as a basal dose along with 60kg Nitrogen and 50 kg in each of Phosphorus and Potash. Forty five days after planting 60kg Nitrogen is applied again as top dressing.
Irrigation for garlic cultivation
Garlic is a bulb crop producing shallow roots. It therefore, requires a good amount of moisture- more than water. Perhaps the biggest challenge in garlic cultivation is being able to ‘moisture it right’. In other words, there should be enough water to maintain a good level of moisture in soil. However, too much water would result in water stress and thus splitting of the bulbs. Too little water or moisture level again means under-developed bulbs. The best way is to irrigate the crop frequently. It must be irrigated:
- Immediately after planting
- At an interval of one week to 10 days depending on the moisture content in soil.
Alternating the irrigation period with a dry spell causes the outer scales of garlic to split. Waterlogging results in development of diseases like purple blotch and basal rot. A continuous irrigation until maturity causes secondary roots to develop. Such crops produce new sprouts and growth. Bulbs from these crops cannot be stored for a long period of time.
Intercultural operations for garlic cultivation
First interculture is given with hand hoe one month after sowing. Second weeding is given one month after the first (about two and half months from sowing) loosens the soil and helps in the setting of bigger and well filled bulbs. The crop should not be weeding out or hoed at a later stage because this may damage the stem and impair the keeping quality.
Plant protection for garlic cultivation
Thrips cause withering of the leaves. Application of methyl demeton 25EC 1 ml/litre will check the incidence. Leaf spot is the most important disease. Spraying Dithane M-45 at fortnightly intervals at 2.5g in one litre of water is recommended.
Harvesting for garlic cultivation
Harvest autumn-planted garlic in early summer and spring-planted from mid-summer to early autumn.
Lift the bulbs with a fork once the foliage starts to fade and go yellow. Avoid delay as the bulbs open up and store less well if lifted late. Handle gently as bruising also reduces their storage potential.
Dry them off thoroughly in a single layer in the sun, under a cloche or in a greenhouse is ideal, taking care to avoid excessive (>30°C) heat by generous ventilation. Alternatively, place in a dry, well-ventilated shed or similar environment. Expect drying to take two to four weeks depending on the weather. If mould is detected deploy a fan heater, but this should be necessary only under exceptional circumstances. Once foliage is no longer moist sever stalks and store bulbs in a dry place at 5-10°C (41-50°F) where further drying will take place.
Yield for garlic cultivation
In garlic 50 to 70 quintals / ha yield is obtained.