Lecture 23
LEMON GRASS
Scientific name : 1. East Indian Lemon Grass - Cymbopogon flexuosus
2. West Indian Lemon Grass - C. citratus
3. Jammu or North Indian Lemon Grass - C. pendulus
Family : Graminae
Economic part : Foliage
Major constituents : Citral (75 to 80 %)
Uses : Used in perfumery and flavouring purposes.
Chief constituent of oil is citral and it is the starting
material for preparation of ionone.
Oil has bactericidal, insect repellent and medicinal
uses.
Importance and chemical composition
• Lemon grass (Cymbopogon flexuosus), belonging to family Poacea, is the source of
lemon grass oil obtained from the leaves and shoots of the plant.
• Lemon grass oil is mainly used in the manufacture of perfumes for soaps, hair oils, scents
and medicines. It also has antibacterial properties.
• Ionone prepared from the citral present in lemon grass oil was one of the most important
raw materials for the preparation of Vitamin A.
• In addition to its use in perfumery, Ionone is used in certain kinds of confectionary and
liquors.
• The oil can be used to improve the flavour of some fish and can be used to flavour wines
and sauces. It can be used for headache, tooth aches, baths, and as a diuretic agent for
fever.
Origin and distribution
The species is considered to have originated in India. It grows wild in many tropical and
subtropical parts of Asia, Africa and America. The plant is grown for its oil in the West Indian
Islands and also in Central America, South America, Thailand, Bangladesh, the Comoros
Islands, Madagascar and China. Although the oil has been known since very early times in India,
the systematic cultivation and distillation of the grass were started in Kerala only about 90 years
ago. At present, it is grown commercially in the Northern district of Travancore and Cochin
(Kerala), Assam, Maharashtra and parts of Uttar Pradesh.
Area and production
Traditionally, India has been the largest supplier of lemon grass oil to the world market
but has ceased to be so any longer. The crop is under cultivation in India in an area of about
2000ha. The production of oil which was 1800t in 1961 -62 has declined to about 400t at present.
The Indian monopoly in the lemon grass trade in the world market has been broken due to the
entry of Guatemala and a few other Latin American states including Brazil and Mexico, Puerto
Rico, Dominica, and China.
Description, types and varieties of the plant
Lemon grass grows to a height of about 3m. The leaves of the plant are linear, lanceolate,
125cm long and 1.7 cm broad. The plant is spreading, 100 -135 cm tall, slightly hairy.
There are two main types of lemon grass namely,
1. The East Indian or true lemon grass (C. flexuosus) and
2. The West Indian lemon grass (C. citratus)
The oil obtained by the distillation of the grass of C. flexuosus called the East Indian oil,
is the genuine oil of commercial importance. It is produced in Kerala and is popularly called the
Cochin oil, since it is shipped mainly from the port of Cochin. A small quantity of oil is also
obtained from C. pendulus, popularly known as North Indian lemon grass or Jammu lemon
grass, since it is grown mainly in Jammu and other North Indian States. The West Indian (South
American) oil of C. citratus is extracted in Indo- China, Madagascar, Guatemala, Brazil, Congo
and West Indies. It is found that the East Indian oil produced in South India is readily soluble in
alcohol. Both the type have practically the same citral content (75-86%), but the West Indian oil
along with citral contains other aldehydes which lower the quantity of the oil. In C. flexuosus the
red stemmed plant with chocolate to purple coloured stems, yields the genuine oil, while the
white stemmed grass does not. Recently a new species C. khasianus has been discovered which
is important for its geraniol content.
Some lemon grass varieties released for cultivation are given below.
Pragati CIMAP, Lucknow
Developed through half-sib followed by clonal selection
Tall, Dark green leaves with dark purple leaf sheath
Suitable for North Indian plains
Herb yield: 350a/ha
Oil yield: 200 kg/ha
Citral content: 85 %
Praman CIMAP, Lucknow
Half-sib seed followed by clonal selection
Medium tall, high tillers, leaf colour light green, leaf sheath light
purple base
Suitable for drought / marginal land
Herb yield: 370 q/ha
Oil yield: 225 kg/ha
Citral content: 75-80 %
Chirharit CIMAP, Lucknow
Developed through clonal selection in Open Pollinated Seedling
Progenies
Frost resistant variety
Herb yield: 256 q/ha
Oil yield: 260 kg/ha
Citral content: 80 %
Krishna CIMAP, Lucknow
Developed as clonal variety through recurrent selection
Light green leaf with leaf sheath colour light purple
Erect plant habit and leaves
Herb yield: 25-30 t/ha/yr
Oil yield: 200-240 kg/ha/yr
Citral content: 75-80 %
T-1 CIMAP, Lucknow
Developed through half-sib seed followed by clonal selection
Medium tall, light green leaf, leaf shealth powdery light purple in
colour
More number of cutting possible
Suitable for lemon aroma tea industries and food industries
Herb yield: 364 q/ha; Oil yield: 181 kg/ha
Citral content: 45-50 %
Nima CIMAP, Lucknow
Developed through half-sib seed followed by clonal selection
Dwarf, dark green leaf, leaf sheath dark purple in colour
High citral content in essential oil, more number of cuttings possible.
Herb yield: 289 q/ha
Oil yield: 261 kg/ha
Citral content: 89 %
CIM-Suwarna CIMAP, Lucknow
Developed through clonal selection
Very fast growing, tall with light green stem
High number of tillers/plant
Leaves are whitish/powdery green
Five number of cuttings / year
Herb yield: 549 q/ha
Oil yield: 208 kg/ha
Citral content: 80 %
GRL CIMAP, Lucknow
Developed through selection
Tall stretcher with light green stem, the high number of tillers/plant
and green long leaves
Herb yield: 275 q/ha
Oil yield: 185 kg/ha
Citral content: 60-65%
Cauvery CIMAP, Lucknow
Tall, citral type
RRL -16 IIIM, Regional Research Laboratory, Jammu
It is evolved from C. pendulus
The average yield of herb is 15-20 t/ha/annum giving 100-110 kg of
oil.
The oil content varies from 0.6-0.8 per cent with 80 per cent citral.
SD-68 CIMAP, Lucknow
It is developed by ionizing radiation
It yields up to 375 kg of oil/ha/yr with citral content of 90-92 %
Sugandhi Aromatic and Medicinal Plants Research Station, Odakkali, Kerala.
(OD-19) It has red coloured stem and is adapted to a wide range of soil and
climate conditions.
The plant grows from 1-1.75 m. height with profuse tillering.
It yields 80-100 kg oil per hectare with 80-88 per cent citral under
rainfed conditions.
CKP 25 RRL, Jammu
An interspecific hybrid of C. khasianus x C. pendulus
It has 0.5 % essential oil with 82-85 % citral
KALAM Regional Research Laboratory, Jammu
(CPK-F2-38) It is an improved F2 derivative of hybrid of C. pendulus x C.
khasianus
Average essential oil yield is 170-190 kg/ha/yr
Oil content: 75-85 %
Tawi Rosa RRL, Jammu
Geraniol rich variety (70-75%)
Cultivation
Soil - It flourishes on a wide variety of soils ranging from rich loam to poor laterite. In sandy
loam and red soils, it requires good manuring. Calcareous and water logged soils should be
avoided as they are unsuitable for its cultivation.
Climate - It requires a warm, humid climate with plenty of sunshine and a rainfall ranging from
about 200- 250cm, well distributed over the year. In areas where the rainfall is poor, it can be
grown with supplemental irrigations. It grows well at altitudes between 1000 -1200 m.
Propagation - Lemon grass is generally propagated through seeds, vegetative propagation and
rooted slips. It is reported that both the seedlings and rooted slips performed equally well, with
respect to growth and yield. But due to high cost of transplanting, direct seeding is widely
practiced, especially over the plains and the terraced lands in Kerala. For raising the crop by
direct seeding a seed rate of 20 to 25 kg/ha is recommended. While sowing, the seeds must be
thoroughly mixed with dry river sand in a ratio of 1:3, to ensure the uniform distribution of seeds
during storage.
Nursery raising - For raising the seedlings required for planting 1ha of land, a 1000m area is
required. The area is well prepared and raised beds of 1 to 1.5m width and convenient length are
made. The recommended seed rate is 3 to 4 kg/ha. The seeds are uniformly broadcasted on the
beds and are covered with a thin layer of soil, followed by watering at regular intervals. The
seeds collected during the month of January – February are usually sown in the nursery during
April – May.
Transplanting - The land is prepared by repeated ploughing and harrowing, and beds of 1 to 1.5
m width and convenient length are made with a spacing of 30 to 50 cm between beds. The beds
are made along the contour of the land slopes. Three to four leaved, 50 to 70 days old seedlings
are planted during the monsoon season (May- June) in Kerala. A spacing of 30cm x 30cm with a
plant density of 1,11,000/ha is recommended. A wider spacing of 60cm x 45cm for seedlings and
90 cm x 60 cm for slips has been recommended for fertile, irrigated land under North Indian
conditions.
Manures and fertilizers - Lemon grass is an exhaustive crop and it requires 275 kg N, 25 kg
P2O5 and 175 kg K2O/ha/annum. In order to promote growth and to obtain a higher oil yield the
crop is applied with 2t/ha of compost made from spent grass and 2t/ha of wood ash at the time of
bed formation. In addition, it has to be supplied with chemical fertilizers. Under Odakkali
conditions, it was found that an application of 100kg N in 3 to 4 split doses was found to be
optimum, though a response up to 200kg was recorded. The response to P and K was found to be
erratic. The application of 50kg ha each P2O5 and K2O as a basal dose gave encouraging results
in West Bengal. It is recommended to apply 60:45:35 kg/ha N, P2O5 and K2O as a basal dose
and 60kg N in 3 to 4 splits/annum as top dressing during the growing season as an optimum
dose. Lemon grass is also reported to respond well to the application of copper, iron, calcium and
sulphur. It is reported from the CIMAP, Lucknow, that a lower dose of boron (2.5ppm) in
combination with chloride salts can be beneficial for the crop.
Interculture - The earthing up of the plant after about 4 months of planting and again after every
harvest is beneficial, as the root region of lemon grass has a tendency to grow above the soil. The
field is kept stubble free. Generally 2-3 weedings are necessary during the year. Among the
herbicides Diuran @ 1.5 kg a.i./ha and Oxyfluorfen @ 1.5 kg a.i./ha are effective for weed
control. Intercultivation can be done by a tractor drawn cultivator or a handheld hoe in row
planted crops. Under rainfed conditions, burning the dry grass and stubble of the standing crop
prior to the onset of monsoon is practiced in Kerala to prevent white ant attack and also to
rejuvenate the old clump. Irrigation After planting if there are no rains, the crop should be
irrigated every alternate day for about a month. It is recommended that 4 to 6 irrigations are
given during the period February to June under North Indian conditions for an optimum yield.
Pests and diseases - Pest infestation is very low for this crop. Several diseases are reported on
lemon grass, but none are serious enough to cause major reduction in oil yield. The leaf diseases
can be controlled by prophylactic sprays of Dithane M-45 and Dithane Z-78 @ 3 g/l thrice at
intervals of 15 days.
Harvesting and yield - The crop is perennial in nature and gives good yields for 5 years.
Harvesting is done by cutting the grass 10cm above the ground level. During the first year of
planting 3 cuttings are obtained and subsequently, 5-6 cuttings per year are taken subject to
weather conditions. The harvesting season begins in May and continues till the end of January.
The first harvest is done about 90 days after planting. The interval from sowing to harvest exerts
a considerable influence on the yield and the quality of oil. Both immature and over mature grass
gives a lower quantity of oil. For the local type of lemon grass, the optimum interval is 40- 50
days. The optimum period of harvesting, when grown on hill tops and low lying areas are 60 and
55 days, respectively. Herbage yield 15t/harvest and oil recovery about 0.3 – 0.5% from fresh
grass can be expected. The oil is obtained by steam distillation. Oil yield of about 350- 400 kg/ha
from the second year onwards is considered satisfactory.
Factors influencing the oil –yield: The factors influencing the oil production during distillation
are: i) Storage of the plant material ii) Treatment of the material iii) The method of distillation.
The cut grass is kept in a dry atmosphere with limited air circulation. The grass when stored in
the shade can increase the oil recovery up to 96 hours and storage for a further period will only
decrease the oil yields. The essential oils are enclosed in the oil glands, oil sacks and glandular
hairs of the plant. Therefore before distillation, the plant material must be cut into small pieces to
enable them to directly expose as many oil glands as is practically possible. Once the plant
material has been reduced in size it must be distilled immediately. Otherwise, the essential oil
being volatile will be lost by evaporation. Dipping the chopped lemon grass in sodium chloride
solution for 24 hr at 1-2 % concentration before distillation has been found to increase the citral
content.
