Garlic is a high value horticultural crop in the onion family. Farmers in most parts of the country can be able to grow it and considerably increase their income because garlic has a good local market.

It is mainly used as food flavouring and for medicinal purposes. Garlic has anti-feedant, insect repellent, bacterial, fungicidal, insecticidal, nematicidal and repellent properties.

Garlic is effective against a wide range of disease-causing organisms and insects at different stages in their lifecycle.

This includes ants, aphids, armyworms, diamondback moth and other caterpillars such as the false codling moth, pulse beetle, whitefly, wireworm, beetle, mice, mites, moles, and termites as well as fungi bacteria and nematodes. Garlic can kill beneficial insects as well.

Therefore, it should be used with caution. When growing garlic for pest control, it has been recommended to avoid use of large amounts of fertilisers. This is because heavy doses of fertiliser reduce the concentration of the effective substances in the garlic.

Very few farmers grow garlic mainly due to lack of knowhow and experience on its production. This is one of the reasons for the poor quality of locally produced garlic; another reason is the stiff competition from China. Very often, farmers sell the garlic even before it has matured and cured properly (hanging and drying in controlled light).

Conditions

Garlic can grow well at an altitude of between 500-2000 metres above sea level. The right temperatures for garlic are between 12-24 degrees Celsius. Extremely high temperatures are not suitable for garlic production.

Excess humidity and rainfall interferes with proper garlic development, including bulb formation. The crop is grown in low rainfall areas where irrigation can be practised, especially in early stages when the plant requires enough water to growth. Adequate sunlight is important for bulb development. Garlic develops its flavour depending on sunlight conditions during growth.

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Garlic requires a fertile, well-drained, light soil. Clay soils should be avoided since they lead to poor bulb development. Soil pH should be between 5.5 and 6.8. Deep soil cultivation is important to ensure rooting depth.

Farmers should seek advice on the garlic varieties suited to local conditions to ensure they get good yields that meet market requirements.

Planting

Garlic is vegetatively propagated. That means that the farmer has to plant individual cloves separated from the main bulb.

Very small cloves should not be used. The larger the cloves, the more the space required for planting. The cloves should be planted in upright position. The bulbs intended for use as seed should be stored at 10Β° C and a relative humidity of 50 -56 per cent. Stored bulbs should be fumigated and continuously inspected to ensure they do not rot.

Spacing

The crop is grown on raised beds or on ridges at a spacing of 30cm between rows and 15cm between the plants, giving a plant population of 15,000 to 20,000 per hectare.

The normal seed clove requirement is 500-700 kilogrammes per hectare. Closer spacing within the rows is possible; but disease risks are also high when garlic is planted too closely; bulb formation is also affected when the cloves are near each other.

The cloves should be planted at 2.5 cm deep in well-firmed, but not compacted soils.

Manure

Garlic does well if well-composted manure is ploughed in before planting. Top dressing with liquid manure should be done regularly at the beginning of 6 – 8 weeks and increased during bulb formation.

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The field should be weed-free to ensure garlic does not compete for nutrients with weeds.

Disease control

The most common diseases are purple blotch, downey mildew, rust and bulb rot (white rot).

They can be controlled through long crop rotation, improved drainage and use of copper based fungicides such as copper oxydchloride, which is accepted in organic farming.