Cul t i vat i onOf Ger ani um
Geranium Area Under Cultivation It is being commercially cultivated mainly in Nilgiri and Kodaikanal hills of Tamil Nadu and around Bangalore in Karnataka.
Botanical Name : Pelargonium graveolens Family : Geraniaceae Plant Discription: It is a bushy aromatic herb. Stem is cylindrical, woody at base. Pubescent, green when young and turning brown with age Leaves are alternate, stipulate, simple with about 5 palmatisect primary lobes and pinnatisect secondary lobes, pubescent on both lobes. Flowers are pentamerous, bisexual with pink corolla.
Centre of Origin : South Africa Pollination System : Generally sterile Chromosome No. : 2n=88
Geranium Diseases Root rot/wilt (Rhizoctonia solani) Root rot/wilt of geranium is observed very often on the crop. In the beginning, only a few plants exhibit the typical wilting find drooping symptoms, which soon attain alarming rate if ignored. Control : The wilt out-break could be minimised by observing the following package of disease management practices. i. At the time of planting, fresh cuttings in nursery beds are dipped in 0.3% Dithane M-45. The nursery bed is also drenched with the same fungicide. ii. Rooted cuttings are dipped in 0.3% Dithane M-45 before transplanting. The soil around the plant is also drenched with the same fungicide. iii. After every harvest or after every heavy rain the soil around the plant is drenched with 0.3% Dithane M-45. iv. Overwatering increases the incidence of wilt, and hence should be avoided. v. Sharp sickles should be used for harvesting to avoid mechanical damage to the plant.
Alternaria Leaf Spot (Alternaria tenius) Small brown spots with alternating light and dark bands are most evident on lower surface of older leaves. It occurs on garden geraniums during cool, wet weather. The fungus rarely sporulates on attached leaves but does so readily on fallen leaves. Control : Removal and destruction of infected foliage and application of foliar fungicides immediately upon the appearance of disease helps to control the disease.
Geranium Harvesting Geranium is harvested about 4 months after transplanting, when there is sparse flowering, leaves start turning light green and exhibit a change from lemon-like odour to that of rose. Though the change in colour and odour is the criterion for harvesting, it requires careful observations and experience to decide the stage of harvesting. Leaf blades have maximum oil followed by petioles and woody parts have negligible oil. Terminal branches with 10-12 leaves are best for oil extraction. They are harvested with a sharp sickle and taken up for distillation immediately. The use of sharp sickle is important since it minimises damage to the crop while harvesting. Harvesting is done manually in sunny weather in the morning hours. The crop after harvesting is maintained by hoeing, fertilizer application and irrigation as per schedule. This helps to put forth fresh shoots and reaches harvesting stage in four months. Thus, a total of three harvests a year may be obtained. The crop is a perennial but it is advisable to replant after two years since the wilt disease may dominate and kill many plants making it uneconomical to maintain.
Yield The quality and yield of oil will be better if the crop is harvested at appropriate maturity. In large-scale distillation, the yield of oil is 0.08%. Occasionally, a yield of 0.1% may be obtained. The yield of fresh herbage per hectare per year from all the three harvests is about 30 tonnes, which on distillation yields about 24 kg of oil. In Bangalore plains, however, yields are around 40 tonnes of herbage/ha/year from which 40 kg oil is produced. The quality of essential oil produced in the plains is quite high.
Oil Contents The oil of geranium is a clear liquid with light-yellow to light-brown or green colour. It has a strong, heavy rose-like odour with a minty top note. The chief constituents of the oil of geranium are geraniol and 1- citronellol, the quantities of which vary in proportion, depending upon the origin. Esters of these alcohols as acetates, formates and tiglates are also present. Other important constituents of geranium oil are isomenthone, linalool, -turpineol, phenyl ethyl alcohol, 3-hexene-1-ol and rose oxides (traces).
Geranium Intercultural Operations Weed Control : The growth of the crop is slow during initial period therefore the crop may require one weeding after about 45 days from planting and one hoeing after each harvest.
Intercropping : Blackgram can be taken up as an intercrop with geranium during the first year in the initial stages of the crop. One row of blackgram is sown between two rows of geranium, subsequent to transplanting of geranium.
Geranium Irrigation The plants establish well if irrigation is given once a day for the first 3-4 days and subsequently on alternate days for 10- 15 days. After this period, irrigation is continued twice a week and the schedule is suitably modified during the winter and monsoon months.
Geranium Manuring & Fertilization Prior to transplanting of the cuttings, 10 tonnes of good FYM is applied. In slightly acidic soils a fertilizer dose of 150kg N and 60kg each of P 2O5 and K2O per hectare is recommended. In North India, fertilizer dose of 175kg N and 60kg each of P2O5 and K2O per hectare is optimum. Foliar application of N is reported to be highly beneficial in increasing herbage and oil yield. Improved oil yield was attributed to increase in the leaf area, bigger epidermal cells and more number of oil glands per unit area. Agromin, a commercial micronutrient formulation, is reported to improve herbage yields when applied at 1% concentration after each harvest.
Geranium Pests Termite : The crop is prone to termite attack occasionally. Mixing 25 kg/ha of 5% BHC solution into the soil and irrigating the area subsequently can easily control this disease.
Geranium Planting Rooted cuttings are carefully dug out from the nursery and dipped on 0.1% Bavistin solution and planted immediately in the field. Before planting, the field should be properly prepared by discing, tiling, application, laying the field into ridges and furrows and irrigating the plot on the previous day. Planting on ridges is recommended. Furrows on the sides facilitate irrigation and also removal of excess moisture, on rainy days. Planting is done at 60 x 60cm spacing and the planted beds are immediately irrigated. Although the seedlings may droop initially, they recover by the following morning.
Geranium Post Harvest Technology Distillation Geranium is distilled soon after it is harvested. The distillation equipment consists of a boiler, distillation stills, condensers and receivers. Distillation still is generally made up of mild steel. It has a perforated metal sheet at the bottom to support the herbage, which is loaded into the still for distillation. Loading and unloading can be mechanised with the help of an overhead chain-pulley block. The lid of the still can be swung aside during loading and unloading. It is important that the herbage should be evenly packed inside the still, otherwise steam channels may form during distillation and result in poor yield. The condenser, which cools the hot vapours received from the distillation still, consists of many tubes made up of copper or stainless steel and mounted inside a jacket. The condenser has inlets and outlets for the circulation of cooling water and for entry and exit of hot vapours and condensate. The condensate flowing out of the condenser drops into the receiver. The oil, being insoluble and lighter than water floats on the top in the receiver and the water gets drained out. The oil can be drawn off separately at the end of the distillation. The receiver is fabricated out of stainless steel and consists preferably of two compartments, so that any oil escaping from one compartment can be retained in the adjoining compartment, although this rarely happens. Distillation is carried out at atmospheric pressure and each distillation takes about 2-3 hours in addition to the time required for loading and unloading.
Geranium Propagation Raising of Seedlings in Nursery There is no seed setting in geranium. Vegetative propagation is, therefore, the only alternative. The cuttings are first raised in a nursery and then transplanted in the field. A nursery area of about 80 sq m is sufficient for planting one hectare crop. Nursery beds of about 3 x 15 m are prepared by thoroughly working up the soil and mixing enough sand so that a porous medium for the seedlings is ensured up to depth of about 12.5 cm. Soil with 5.5 pH is most suitable for efficient rooting. About 100 g of superphosphate is also mixed well into the surface soil of each bed. Fresh terminal cuttings, about 20 cm long and consisting of about 8 nodes, are taken from healthy and well-grown geranium plants. These are transferred to shade immediately and trimmed by removing all leaves except the first 3-4 leaves from the terminal end. A slant cut is made with a sharp knife just below the 6th or 7th node and the cuttings are dipped in 0.3% Dithane M-45 solution. To encourage early rooting Seradix B-2, a rooting hormone is applied to the cut ends. The nursery beds are also drenched with Dithane M-45 and then the cuttings are planted with the help of a suitable dibbler at a spacing of about 5 cm. The beds are hand-watered immediately. Watering is carried out daily, twice during the first 3- 4 days and once in subsequent days. Geranium wilts under hot sun. The cuttings should therefore, be made with great care and the nursery areas should be properly sheltered against hot sun. Bright sun, heavy wind and rains damage the cuttings very fast and result in poor establishment. Considering all these factors, November and December are the best suited months for raising geranium nursery. About one month after planting of the cuttings, good drench with 0.2% urea may be given 2 or 3 times at weekly intervals. The cuttings will be ready for transplanting in about two months after planting. If propagation is undertaken in a mist chamber with a mist duration of about 10 seconds every 5 minutes, rooting of the cuttings can be accomplished within about 20 days time. The use of mist chamber would also circumvent the climatic hazards in raising nursery. Raising of cuttings in small (11 x 15cm) polythene bags filled with a mixture of sand + FYM or in sphagnum moss facilitates transplantation without disturbance and damage to roots, which ensures high survival percentage in the field.
Geranium Soil & Climate Soil Geranium thrives well in calcium rich porous light soil with pH of 5.5 to 8.0 that does not retain moisture during winter or rainy season. It is successfully cultivated on the hill slopes of Nilgiris along contours and on hill terrace. It grows equally well in the well-drained red sandy loam soils in the plains of Karnataka and Andhra Pradesh.
Climate Geranium can grow in temperate, sub-tropical and tropical climates. Temperature range of 5-23째C and rainfall ranging from 750mm of the plains up to 2750 mm of Naduvattam in Nilgiris is ideal for its cultivation. It has been successfully cultivated at altitudes from 530 m to 2400 m. At altitudes of 2400m and beyond the crop suffers adversely from frost damage. The crop is quite drought resistant but a long spell of dry weather is known to greatly diminish the oil yield.
Geranium Varieties Algerian or Tunisian : It is a slender plant with dark pink coloured flowers. It is cultivated in Nilgiris. This variety yields 50-60% more oil than the reunion type.
Reunion or Bourbon : It is grown in Nilgiri and Annamalai hills. The plant is sturdy with light pink flowers and suited for wet conditions. The oil content is higher during summer season and the terminal 6-10 leaves contain more oil than the middle and basal portion.
Sel-8 (Reunion Type) : It is a variety released by IIHR, Bangalore.
Hemanthi : This variety is released by CIMAP, Lucknow for cultivation in the plains of north India. It is same as Algerian type rich in citronellol.
Bipuli : This variety is released by CIMAP, Lucknow. It is the same as Bourbon type equally rich in both geraniol and citronellol.