Clove

Introduction

Requirement

Propagation

Nursery practices

Land preparation and planting

Fertilizer

After cultivation

Plant protection

Pest

Stem borer

Scale insects

Disease

Leaf rot

Harvesting and yield

Curing

 

 

 

Introduction

Clove (Syzygium aromaticum), the dried unopened flower bud of the evergreen tree is an important spice noted for its flavour and medicinal values. The important clove growing regions in India are the Nilgiris, Tirunelveli and Kanyakumari districts of Tamil Nadu, Calicut, Kottayam, Quilon and Trivandrum districts of Kerala and South Kanara district of Karnataka. Food processing uses both whole and ground form of cloves in various preparations. Clove oil is used in perfumeries, pharmaceuticals and flavouring industries.

Requirement

  • Climate

Clove is strictly a tropical plant and requires a warm humid climate having a temperature 20-30 oC. Humid atmospheric condition and a well distributed annual rainfall of 150-250 cm are essential.

  • Soil

Deep black loam soil with high humus content found in the forest region is best suited for clove cultivation. It also grows on laterite soils, clay loams and rich black soils having good drainage. Sandy soil is not suitable.

Propagation

Clove is propagated through seed, which is called mother clove. The seeds become available from June to October. Fruits are allowed to ripe on the tree itself and drop down naturally. Such fruits are collected from the ground and sown directly in nursery or soaked in water overnight and the pericarp removed before sowing. They lose their viability within one week after harvest. Hence they must be sown immediately after collection from a tree.

Nursery practices

Beds for sowing seeds are of 15-20 cm height, one metre width and a convenient length. The beds should be made of loose soils and over which a layer of sand may be spread (about 5-8cm thick). Seeds are sown at 2-3 cm spacing and a depth of about 2cm. The seed beds have to be protected from direct sunlight. The germination commences in about 10-15 days and may last for about 40 days. In higher elevations, germination is delayed considerably. The germinated seedlings are transplanted in polythene bags (30cm x 15cm) containing a mixture of good soil, sand and well decomposed cowdung (in the ratio of about 3:3:1). The seedlings are ready for transplanting in the field when they are 18-24 months old. The nurseries are usually shaded and irrigated daily to ensure uniform stand.

Land preparation and planting

Before monsoon and pits of 60-75cm3 are dug at a spacing of 6-7 metres. The pits are partially filled with compost, green leaf of cattle manure and covered with top soil. The seedlings are transplanted in the main field during the beginning of rainy season, in June-July, and in low lying areas, towards the end of the monsoon, in September-October. Cloves prefer partial shade. Immediately after planting, mulching with available transhes are recommended.

Fertilizer

Age of the plant

Cattle manure
or compost (kg)

Urea

Super
Phosphate

Muriate
of Potash

G/tree

First year

15

-

--

-

Second year

20

80

220

160

Annual increase per year

5

40

110

80

Tree of 15 years and above

50

600

1560

1250

The entire quantity of organic manures and half the quantity of fertilizers may be applied during May-June and the remaining quantity of fertilizers is applied in October-November in shallow trenches dug around the plant normally about 1-1.5m away from the tree base.

After cultivation

No intercultivation, except removal of weeds is usually done for clove. Thinning of branches occasionally may keep the growth within manageable proportion. Dead and diseased shoots should be removed periodically. Irrigation is necessary in the initial stages. In places where pronounced drought is normally experienced, pot watering is recommended to save the plants in the initial two or three years. Although the trees can survive without irrigation, it is advantageous to irrigate the grown up trees for proper growth and yield.

Plant protection

Pest

Stem borer

The pest bores into the main stem, causing death of the plant.

  • Control

Swab the surface of the stem with chloropicrin.

Scale insects

Infestation is seen on leaves and tender shoots, more often in the nursery.

  • Control

Spray 0.05% monocrotophos.

Disease

Leaf rot

Dark patches are seen in leaves of mature trees seedlings, which often result in rotting of whole leaves or tips severe defoliation.

  • Control

Spray 0.2% carbendazim.

Harvesting and yield

Clove tree begins to yield from the seventh or eighth year after planting and full bearing stage is attained after about 15-20 years. The flowering season is September-October in the plains and December-February at high altitudes. The optimum stage for picking clove buds is indicated by the change in the colour from green to slightly pinkish tinge. The matured clove buds are carefully picked with hand. When the trees are tall and the clove bunches are beyond the reach, platform ladders are used for harvesting. A well maintained full grown tree under favourable conditions may given 4-8 kg of dried buds. The average annual yield after 15th year may be taken as 2kg per tree. Clove oil, the spice determining factor, is about 16-21 per cent in the buds.

Curing

The harvested flower buds are separated from the clusters by hand and spread in the drying yard for drying. It takes normally 4-5 days for drying. The correct stage of drying is reached when the stem of the bud is dark brown and the rest of the bud lighter brown in colour. Well dried cloves will be only about one-third of the weight of the original. About 11,000-15,000 dried cloves make one kilogram.