Cardamom, popularly, known as Queen of Spices is native to the evergreen rainy forests of Western Ghats in South India. Botanical name of the cardamom is Elettaria cardamomum (L.) Maton, which belongs to the family Zingiberaceae. It is cultivated in about 1,00,000 ha mainly confined to the Southern State viz., Kerala, Ktaka and Tamil Nadu accounting for 60, 31 and 9% of the total area respectively. Our annual production is about 40000 metric tonnes and nearly 40% of which is exported to more than 60 countries earning a foreign exchange of nearly 60 million rupees. Cardamom is used for flavouring various preparations of food, confectionary, beverages and liquors.
Cardamom is a herbaceous perennial having underground rhizomes. The aerial pseudostem is made of leaf sheaths. Inflorescence is a long panicle with recemose clusters arising from the underground stem, but comes up above the soil. Flowers are bisexual, fragrant, fruit is a trilocular capsule. Flower initiation takes place in March-April and from initiation to full bloom, it takes nearly 30 days and from bloom to maturity, it takes about 5 to 6 months.
It is a perennial crop, propagated from the seeds or cut bits of the rhizome. It starts bearing in 3 to 5 years after planting and the economic age of the plantation is 12 to 15 years. The fruits are about 2.5 cm long, ovoid and triangular in shape brown or pink in colour when ripe. They contain 40 to 50 seeds. Average yield is 300 to 1000 kg per ha from 4th or 5th year.
Climate and Soil
The natural habitat of cardamom is the evergreen forests of Western Ghats. It is grown in the areas where the annual rainfall ranges from 1500 to 4000 mm, with a temperature range of 10 to 350C and an altitude of 600 to 1200 m above MSL. Rainfall distribution should be good and summer showers during February-April are essential for panicle initiation, otherwise it will affect the yield.
Based on the size of the fruit, two varieties are broadly recognised viz., Elettaria cardamomum var. major consisting of wild indigenous types and var. minor comprising the cultivated types viz., Mysore, Malabar. Recently a number of improved cultivars have been released for cultivation.
New cardamom varieties
Cardamom is propagated mainly through seeds and also through suckers each consisting of atleast one old and a young aerial shoot. The suckers are commonly used for gap filling but suckers may not be available in larger numbers. Therefore, a rapid clonal multiplication technique evolved by N.R.C.S., Cardamom Reserch Centre, Appangala, is proved to be quick, reliable and economic for production of large number of quality planting materials. The site selected for this method should have a gentle slope and must be nearer to the water source.
Trenches of 45cm width, 45cm depth and of any convenient length may be taken across the slope or along the contour at 1.8 m apart. The top 20cm depth soil is excavated separately and heaped on the upper side of the trench. The lower 25 cm depth soil is excavated and heaped on lower side of the trenches all along the line. The top soil is mixed with equal protions of humus rich jungle soil, sand and cattle manure and filled back by leaving a depression of 5cm at the top to facilitate mulching for retention of soil mixture. Suckers, each consisting of one grown up tiller and a growing young shoot, are placed at a spacing of 0.6 m in the trenches during March-October.
Regular cultural operations are to be followed including a high fertilizer dose of 100:50:200 kg NPK/ha in 6 split doses at 60 days interval along with neem cake at 250 g/plant. Irrigation should be provided atleast twice a week. Over head pandal at a height of 3.6m covered with coir mat or leafy twigs of any shade tree may be provided during the non-rainy season or pandal at a height of 3.6m covered with coirmat. Within a period of 12 months, a plant would produce atleast 32 to 42 suckers which may yield at least 16 to 21 planting units. i.e. about 1.5 lakhs planting units per ha. of clonal nursery within 12 months of planting.
Seedlings are normally raised in primary and secondary nurseries. The nursery site should be selected on gentle slopy lands, having an easy access to a water source. Raised beds are prepared after digging the lands to a depth of 30-45 cm. The beds of 1m width and convenient length raised to a height of about 30cm are prepared. A fine layer of humus-rich forest soil is spread over the beds. Seeds are to be collected from well ripe capsules. Immediately after harvesting, the husk is removed and the seeds are washed repeatedly in water for removing the mucilaginous coating. After draining the water, the seeds are to be mixed with wood ash and dried in shade for a day. In order to ensure uniform and early germination, seeds should be sown immediately after extraction. If the sowing is delayed, pre-sowing treatment of seeds with 25% Nitric acid for 10 minutes is advisable to get a quick and higher germination. One kg of seed capsules may produce 5000 seedlings.
Sowing may be taken up during November-January and is done in rows. Deep sowing of seeds has to be avoided for better and quick germination. Seedbeds are to be dusted with BHC 10%. Beds are mulched to a thickness of 2 cm with paddy straw or any locally available material and are watered regularly. The germination commences in about 30 days and may continue for a month or two. After germination, the mulch is to be removed. As overhead pandal with a height of 2 m is quite desirable. Materials like coir mat, plaited coconut leaves or tree twigs, which do not shed their leaves easily, may be used but the coir mat is preferred as it allows uniform filtered sunlight.
The excess seedlings are to be thinned out after 75-80 days of sowing. The thinned out seedlings may be used for gap filling within the nursery bed or for raising secondary nursery. When the seedlings attain 5-6 leaf stage, light earthing up is to be done. This would encourage better tillering and proper growth of seedlings. Generally in Kerala and Tamil Nadu, the seedlings are transplanted to the secondary nursery when they attain four to six leaf stage. The beds are prepared in the same manner as that of a primary nursery. Seedlings are transplanted in March-May at a spacing 20x20 cm and mulched immediately. Beds are to be covered with an over head pandal and should be watered regularly. Recently, instead of secondary nursery beds, the seedlings are also raised in polybags containing rich forest soil.
Manuring at the rate of 90g Nitrogen, 60g Phosphorus and 120g Potash per bed of 5x1m size, in three equal split doses at an interval of 45 days is recommended to produce healthier seedlings. The first dose of fertilizer may be applied 30 days after transplanting in the secondary nursery. In Ktaka, 10 months old seedlings are used for planting in the main yield, while in Kerala and Tamil Nadu, 18 months old seedings are commonly used.
Preparation of land
All under growth should be cleared and excess shade trees or branches should be thinned out to have an even overhead canopy. Pits of 45 x 45x30-cm size are dug in April-May and filled with a mixture of topsoil and compost or well-decomposed farmyard manure. In slopy land, contour terraces may be made and pots may be taken along the contour. The spacing adopted in Ktaka for the Malabar type is 2x2 m between plants and rows. In Kerala region 2-3 on either side is adopted. Staggered trenches may be taken across the slope to conserve run off rainwater. The soil collected in trenches may be utilised for earthing up during the post-monsoon period.
The planting is carried out during the rainy season commencing from June. Under Eastern Ghat hills, July planting is adopted. Seedlings are to be planted upto the collar region for better growth. Cloudy days with light drizzle are ideal for planting.
It is an important cultural practice in cardamom. Fallen leaves of the shade trees are utilised for mulching. Sufficient mulch should be applied during November-December to reduce the ill effects of drought, which prevails for nearly 4 to 5 months during summer. Exposing the panicle over the mulch is beneficial for pollination by the bees.
Depending upon the intensity of weeds, 2 to 3 rounds of weeding are necessary in a year. The first round of weeding is to be carried in May-June, the second in August-September and the third in December-January. In slopy land slashing of weeds is alone to be carried out otherwise it encourages to more soil erosion. Weedicides like paraquat @625 ml in 500 litres of water may be sprayed in the interspaces between rows leaving 60 cm around the plant base.
Trashing consists of removing old and drying shoots of the plant once in a year with the onset of monsoon under rainfed conditions and 2-3 times in high density plantations provided with irrigation facilities.
Cardamom being a pseophyte, is very sensitive to moisture stress. Shade helps to regulate soil moisture as well as temperature and provides congenial microclimate for cardamom. Excess shade is also quite detrimental and shade has to be regulated so as to provide 50-60% filtered sunlight. Cardamom plants can tolerate less shade in areas where well-distributed and adequate rainfall is received. In South India, many trees are available in the natural habitat to provide shade but an ideal shade tree should have a wider canopy, minimum side branching and it should not shed the leaves during flowering phase of Cardamom so as not to affect pollination. Some of the common shade trees in Cardamom estates are Palangi (Artocarpus frazinifolius), Jack, Red cedar (Cedrella toona), Karimaram (Diospyros ebenum) and Elangi (Mimusops elangi). The temporary shade trees like Erythrina lithosperma and E.indica are most unsuitable as they compete for nutients and soil moisture.
In order to provide adequate light during monsoon, shade regulation may be taken up before the onset of monsoon. A two-tier canopy with a height of not more than 3 m between the lower and higher canopy may be maintained. Areas exposed to western side should have adequate shade.
After the monsoon is over, a thin layer of fresh fertile soil, rich in organic matter may be earth up at the base of the clump, covering up to the collar region by scraping between the rows or collecting soil from staggered trenches/check pits. This encourages new growth.
In order to overcome the day spell during summer, it is necessary to irrigate the crop to get maximum production as it helps in initiation of panicles, flowering and fruitset. Depending on the moisture holding capacity of soil and topography of the estates, they may be irrigated at an interval of 10 to 15 days till the onset of monsoon. Sprinkler irrigation and or drip irrigation at the rate of 4 litres per clump per day during dry months increases the yield.
A fertilizer does of 75 kg Nitrogen, 75kg Phosphorus and 150 kg Potash per ha is recommended under irrigated condition for high yielding plantations yielding 100kg/ha and above and a dose of 30:60:30 kg/ha is recommended for gardens under rainfed condition. Besides, organic manures like compost or cattle manure may be given @ 5kg per clump. Neem oil cake may also be applied @ one kg per clump. Foilar application of urea at 3%, single super phosphate at 1%, and muriate of potash at 2% is also beneficial to improve the yield. In places were zinc deficiency is noticed, spraying of zinc 500 ppm twice in a year, April-May and September-October is recommended.
Fertiliser is applied in two split doses. The first application during May will help in the production of suchers and development of capsules and the second application during late September will help the initiation of panicles and sucker. Only half the dose of fertilizer is to be applied during the first year and full does is given from second year onwards. Being a surface feeder, deep placement of fertiliser is not advocated. Application of fertiliser is done at a radius of 30cm and covered with a thin layer of soil.
Harvesting and processing
Cardamom plants normally start bearing two years after planting. In most of the areas the peak period of harvest is during October-November. Picking is carried out at an interval of 15-25 days. Ripe capsules are harvested in order to get maximum green colour during curing.
After harvest, capsules are dried either in fuel kiln or electrical drier or in the sun. It has been found that soaking the freshly harvested green cardamom capsules in 2% washing soda solution for 10 minutes prior to drying helps to retain the green colour during drying. When drier is used, it should be dried at 45 to 500C for 14 to 18 hours, while for kiln, over night drying at 50 to 600C is required. The capsules kept for drying are spread thinly and stirred frequently to ensure uniform drying. The dried capsules are rubbed with hands or coir mat or wire mesh and winnowed to remove any foreign matter. They are then sorted out according to size and colour, during storage. These bags are then kept in wooden chambers.
Important pests and diseases affecting cardamom are given below with their typical damages/symptoms and control measures.