CLIMATE AND SOIL
is a cool season crop, hardy to frost but less sensitive to heat.
It is adopted to a temperature range of 13-24ºC. For good vegetative
growth 15-21ºC temperature before bulbing and 20-25ºC for bulb development
are suitable. The optimum temperature for seedling growth is 20-25ºC.
Growth starts declining at temperatures higher than 27ºC.
requirement of day length of different varieties may differ. Kharif
onion varieties require day length of 10-11 hours, whereas rabi
varieties require relatively higher temperature and 12-13 hours
day length. Long day varieties do not bulb under short day whereas
short day varieties, if planted under long day, develop bulbs.
for onion should be deep friable and highly fertile. Onions can, however,
be grown in all types of soils. Sandy soil needs more and frequent irrigation
and favour early maturity, whereas heavy soils give rise to mis-shapen
bulbs causing problem in digging of bulbs. For high yield and quality
bulbs, cool soils are ideal. In general, sandy loam to clay loam soil
is recommended. The optimum pH range is between 5.8 and 6.5. Highly alkaline
and saline soils are not suitable for onion cultivation. Salt concentration
above 4 mmhos/cm² inhibits vegetative growth of most of its cultivars.
Good drainage is essential. Waterlogging can result in failure of crop.
Onions are very much sensitive to the effects of high water table.
Onion seeds are sown in nursery beds to raise seedlings. Best
time for sowing early-kharif crop is February-April in South, May-June
in Maharashtra and other parts, August-September for late-kharif
and October-November for rabi in plains all over the country. In
hills (higher altitudes), March-April is ideal sowing time. Raised beds
of about 3 m long, 0.6 meter wide and 20-30 cm high are prepared. About
70cm distance is kept between 2 beds to carry out operations of watering,
weeding etc. The surface of beds should be smooth and well-levelled. Raised
beds are necessary to avoid problem of waterlogging in heavy soils. In
sandy soils, however, sowing can be taken up in flat beds. Sowing should
be done in lines spaced at 5-7 cm distance. Before sowing, seed should
be treated with thiram @ 2 g/kg of seed to avoid damage from damping off
disease. The soil of nursery should also be treated with thiram or captan
@ 4-5 g/ m² area. The nursery beds should be irrigated 15-20 days before
sowing and covered with 250 gauge transparent polythene for soil solarization.
Application of Trichoderma viride @ 1,250 g / ha is also recommended
to manage damping off and raise healthy seedlings. The seeds after sowing
should be covered with fine powdered farmyard manure or compost followed
by light watering. The beds should then be covered with dry straw or grass
or sugarcane leaves to maintain optimum temperature and moisture. Watering
should be done by a water can as per the need till germination is completed.
Dry straw or grass is removed immediately after germination is completed.
Delay in removal of dry straw and grass may result in lanky seedlings.
In case there is still problem of damping off disease
the drenching with thiram @ 2-3 g/ litre of water should be undertaken.
Weeding and hoeings are carried out to manage weeds. Stomp ( Pendimethalin
30 EC) @ 2.5 litres/ha can be applied even before sowing to manage
weeds economically during rainy season wherever there is labour
scarcity. About 6-7 and 8-9 weeks old seedlings are suitable for
transplanting in kharif and rabi seasons respectively.
If lower aged seedlings are transplanted establishment is poor and
if over-aged seedlings are planted there is a problem of premature
For getting early kharif crop small bulblets of
kharif onion varieties like Agrifound Dark Red, Baswant 780,
N53 and Arka Kalyan raised in previous season are used for planting.
Seeds @ 15 g/m² are sown on raised beds or in flat beds. Carbofuran
@ 1 kg ai/ha should be mixed in soil for managing thrips insects.
Best time for sowing of seeds for getting quality bulblets is mid-January
to early February depending upon the area. All other operations
for raising of bulblets are the same as that of nursery for transplanting.
The plants are left in the nursery bed up to April-May till there
is top fall. Harvesting is done along with the tops. Selected bulblets
(1.5 - 2.00 cm) are stored by hanging method till August in a well-
ventilated house. Bulblets below 1.5 cm if planted do not establish
and sprout but rot. Large sized bulblet result in more doubles and
bolters, increasing cost of production.
in beds or sowing in rows
Seeds of big onion varieties are sown directly
in rows 30 cm apart in parts of Chitradurga, Bellary and Dharwad
districts Karnataka and Satara district in Maharashtra. They are
thinned later to give proper spacing for development of bulbs. Seeds
of small onion ( Bangalore Rose, Agrifound Rose and Arka Bindu )
are broadcast in small flat beds which are thinned later. After
sowing, hoeing is done by hand-hoes to allow seeds to reach to a
depth of 2.5-3 cm. Light irrigation is given immediately after covering
the seeds. Weeding is recommended at 10 days interval for healthy
and stout seedlings.
sowing in rows
of bulblets in multiplier onion.
In multiplier onion ( Agrifound Red, Co-3 and Co-4 ), bulblets are separated
and planted. The bigger-sized bulblets should be selected for planting
to get higher yields of bigger sized bulbs.
common big onions, 8-10 kg seed is sufficient for raising seedlings for
one hectare, accomodating 100-110 beds of 3m X 0.6m size each. For broadcasting
directly in the field or sowing in the rows, 20-25 kg seeds is enough
for a hectare. For multiplier onions 10-12 quintal bulblets are required
for planting one hectare.
general,soil for onion growing should be liberally manured and fertilized.
About 20-25 tonnes of farmyard/ha adequate. The requirement of nutrients
depends on soil type, region of growing, varieties and removal of major
nutrients. Onion crop yielding 300 q/ha removes 73 kg nitrogen, 36 kg
phosphorus and 68 kg potassium. As it depends on the variety, season etc.
soil analysis for application of fertilizers is preferred.
Farmyard manure should be applied one month before
transplanting / planting or sowing and mixed well in the soil. Whole
quantity of phosphorus, potassium and half of nitrogen should be
mixed in the soil before transplanting. Remaining half of nitrogen
should be given as topdressing in single dose in bulblet method
of planting in big onions and bulblet method of planting in multiplier
onion 20-25 days after planting. In transplanting method, topdressing
is taken up in 2 split doses and first dose should be applied at
30 days after transplanting whereas second dose 45 days after transplanting.
The topdressing must be completed before initiation of bulbing.
Delayed application results in thick neck or doubles.
dressing onion crop
addition to fertilizer, application of micronutrients is beneficial in
improving the quality of bulbs. Application of zinc copper and boron increases
the yield and enhances quality of bulbs by increasing TSS, sugar and ascorbic
should be ploughed to a fine tilth by 4 -5 times with a sufficient interval
between two ploughings. The ploughings should be done by tractor-drawn
implements or deshi plough. The ploughing should be shallow as
most of the onion roots penetrate to a depth of not more than 5-6 cm.
The planking should be done for proper leveling. The field is then divided
into beds and channels. The normal width of a bed should be about 1.8
m.The length may, however, vary according to level of land but it is better
to have small-sized beds for proper irrigation and other cultural operations.
Seedlings are usually transplanted in flat beds.
Transplanting on raised beds or on both sides of ridges is, however,
better for kharif or rainy season crops. Flat beds of 1.8
m wide and 7.2 m length depending upon level of land, soil type
and irrigation method, are prepared. Seedlings (6-7 weeks old) are
ideal for transplanting in kharif season, while 8-9 weeks
old seedlings are recommended for rabi crop. Over-aged seedlings
if planted , bolting increases. In case of younger seedlings, establishment
Maharashtra, best time of transplanting for kharif onion is July-August.
In North, it is mid or end of August. In other parts too, August is best
time for transplanting. In Tamil Nadu and Andhra Pradesh, kharif crop
is raised by planting early. Transplanting is done in April-May in Tamil
Nadu whereas in Andhra Pradesh, it is done in May-June. Late kharif
crop in Maharashtra is sown in August-September and transplanted in October-November.
rabi the best time of transplanting in Northern and Eastern India,
is December-end to first week of January. In other parts mid December
is the best time. In Eastern states, where onion is raised after paddy,
the transplanting is done in October-November. Nashik and Karnal mid December
planting of Agrifound Light Red and Pusa Red gives higher yield. In Northern
mid-hills,onion is transplanted during November and April. Dipping of
seedling roots in fungicide and insecticide solution before transplanting
helps in better establishment of seedlings.
pickling onion is planted 3 times in a year in Karnataka, i.e. March-April,
June-July and September-October. In Andhra Pradesh,onion is planted in
spacing depends upon the variety and size of bulbs. In common big onions
an spacing of 15 cm from line-to-line and 10 cm from plant to plant is
ideal. At Karnal 150 kg N and 15 cm x 10cm spacing while at Nashik 100
kg N and 15cm x 10cm spacing give higher yields. For small pickling onion,
8 cm x 5 cm spacing has been recommended if crop is raised by transplanting
method. If bulblets are used for raising big onion crop, ridges are prepared
at 30- 45 cm distance and bulblets of kharif onion and multiplier
onion bulblets are planted at 10-12 cm distance . For getting quality
bulbs, 1.5-2 cm sized bulblets are considered best for planting. Establishment
is, however, a problem in smaller-sized bulblets, 2-2.5 cm sized bulblets
have been recommended for getting highyer yield.
is shallow-rooted crop. Its root system is normally restricted to top
3 cm and roots penetrate seldom deeper (15 cm). The water requirement
of its crop at initial growth is less. It depends on crop growth, soil
type and planting season.
One irrigation is necessary immediately after transplanting
particularly in rainy season in Northern India where temperature
at the time of transplanting is very high. Wherever, there is erratic
power supply in rainy season, transplanting is recommended 8 hours
after irrigation particularly in Karnal area. In kharif season
depending upon the rains 8-10 irrigations are enough. Late-kharif
crop requires 12-15 irrigations while in rabi seasons 15-20
irrigations are given. At bulb formation, irrigation is necessary
and moisture stress at this stage results in low yield. The field
should not be kept dry for long which otherwise results in splitting
and also force maturity. Frequent and light irrigation at weekly
intervals in general (2 acre inch per irrigation) results in good
bulb development and increase in yield. Sprinkler and drip irrigation
methods increase onion yield significantly . Irrigation should be
stopped when tops mature and start falling in rabi season.
In kharif season it should be stopped 10 days before harvesting.
Last irrigation 10-15 days before harvesting gives lower storage
falling in onion
are to be kept down to get a good yield of onion. Stomp @ 3.5 litres/ha
applied 3days after transplanting plus 1 hand weeding at 45 days in rabi
onion. While in kharif onion Stomp @ 2.5 lit/ha with 1 hand-weeding
is very effective. Oxyflurofen @ 150-250 g/ha with one hand-weeding is
also effective. Other weedicides used in onion are Lasso, Ronstar, Dual,Treflan
and Raft etc.
Use of Cytozyme @ 0.2% as root dipping spray at
15 and 45 days after transplanting, dipping seedling roots for 20
minutes before transplanting and foliar sprays are found more effective
in bulbs development and higher yield of kharif onion at
Nashik and Karnal. Use of MH to check premature bolting and sprouting
in storage is recommended. MH @ 2000 ppm applied 75 DAP for kharif
onion and @ 2500 ppm just before neck fall in rabi onion are recommended.
Harvesting takes in 45-90 days from field setting
for green onions and 65-150 days for bulb depending upon variety
/ types. Bulbs are considered to be mature when the neck tissues
begin to soften and tops are about to abscise and decolourise. Development
of red pigment and characteristic pungency of variety are also important
harvesting indices of onion.
for sale as dried bulbs or for storage should be harvested after tops
have started falling over. Best time to harvest rabi onion
is one week after 50% tops have fallen over. In kharif season
since tops do not fall, soon after the colour of leaves changes to
slightly yellow and tops start drying, red pigmentation on bulbs develop
and also true shape and size develop, bulbs are harvested and kept
in windrow for drying the tops. Small picking and multiplier onions
are harvested when 50% - 75% of tops have fallen over. The leaves
are cut leaving about 2-2.5 cm tops above the bulb after complete
drying. Leaving the tops intact until complete drying increases dry-matter
content which might be due to greater loss of water from the bulbs
with intact foliage or due to movement of materials from the tops
to the bulbs. If tops are cut too close, the neck does not close well
and decay organisms have easy access to the bulb. Early harvesting
results in sprouting of bulbs while late harvesting results in formation
of secondary roots during storage. In kharif season late harvesting
results in doubles and bolting.
big onions give 25-30 tonnes/ha yield, small pickling onions give 16-20
tonnes/ha and multiplier onions 15-18 tonnes/ha.
Agrifound Dark Red variety is grown during kharif
and thus seed can be produced within one year. The seeds are
sown in may-June for harvesting of bulbs in October-November. Selected
bulbs are planted in November-December to produce seed in April-may
for use in the next season. The production technology has been standardized.
ready for harvesting
of bulbs, land preparation and planting
bulbs (4.5-6.5 cm for big onion and 2.5-3 cm for small onion) should be
selected for planting. Last week of October to first fortnight of November
is recommended for planting of bulbs. Kharif onion since is available
in November-end or December beginning, bulbs could be planted by 15th
December from the same crops and this way seed production can be taken
within an year. Maharashtra, Madhya Pradesh, Gujarat and Rajasthan are
ideal for higher seed production without much damage from diseases. Seed
should never be produced in plains of Tamil Nadu because bulbs do not
get conditioning thereby number of sprouts are 2-3 as also whatever seeds
are formed these are not of good quality. Big-sized bulbs increase in
number of sprouts/scapes and thereby produce more seed yield per ha. It
is, however, better to select medium-sized bulbs for economic seed production.
The main objection in small size is that they do not express the true
character of the varieties, making it difficult to rogue off types. The
best planting time is October-end or November. If planting is done early,
the crop gets damaged from rain which comes in March/April. If late planting
is done, vegetative growth is less and due to this there are lesser number
of flowers and also the seeds in umbel. Attack of the thrips is also more.
Selected bulbs of 4.5 - 6.5 cm size are planted in well-prepared field
at 45 x 30cm distance in normal loam to clay loam soil. If spacing is
kept closer because of less ventilation, drying of field is slow after
irrigation, thus heavy dew and rains favour disease. In sandy soils, spacing
may, however, be reduced to even 30cm x 30cm. The depth is kept 7.5 cm.
Irrigation is given immediately after transplanting.About 25 to 30 quintal
bulbs for big onions and 15-18 quintal bulbs for small onions are enough
to plant one ha/area. Seed crop also needs to be fertilized each with
80-100 kg of N, 60 kg of P2O5 and 50 kg K/ha. If
soil is low in nitrogen, 120 kg N/ha should be applied. 50% N and full
dose of P and K should be applied as basal dressing and rest half of N
should be applied as topdressing 45 days after planting. Weedicides like
pendimethalin at 2.5-3.5 lit/ha or oxyflorofen at 0.15-0.25 litres ha
with 1 handweeding at 45 days given good control of weeds.
is given at 7-10 days interval depending on types of soil and season.
Earthing is done 2 months after transplanting to avoid lodging. Weeding
and hoeing are done as per requirement. Specific precautions are taken
to irrigate the crop more frequently during flowering and seed setting
stages. Saturating soil surface and keeping it wet, however, should be
avoided as this facilitates in the development of rots and other diseases
which cause seed stalks to die prematurely.
onion is highly cross-pollinated crop, an isolation distance of 500 m
is kept between 2 varieties. This is necessary in case of pedigree or
certified seed production. For stock or foundation seed production, isolation
distance should be kept 1000 m.
Diseased and off type plants are rogued out before flowering for quality
seed production. Because onion is a highly cross-pollinated that too by
bees, it is necessary to have good number of bees for better pollination
and seed setting. Following points should be taken care of for improving
- Bee colonies
should be kept in field.
should be given more frequently at the time of flowering and seed setting.
- Only safer
insecticides should be sprayed during flowering.
- In case
of high wind, sometimes bees do not sit on the flowers. To avoid this
plant wind breakers all round the field.
and post-harvest management
All seed heads do not mature simultaneously, therefore,
harvesting is done in installments. When seed inside capsules become
black and 20 - 25% black seeds are exposed, the umbels are cut with
10 - 15 cm of stems attached. The heads are spread on ground or
canvas to avoid attack of mould and obtain uniform drying.
is threshed when the capsules are brittle and break readily. Threshing
is done by flairing methods. Cleaning is done by air screen machine by
using 1/14 x ½ as grading screen. Cleaning is also done by water dipping.
For this seeds are dipped in water for 2 - 3 minutes. The heavier seeds
at bottom are taken out and spread on screen bottom trays for immediate
drying. Dipping in no case is done for more than 2-3 minutes as otherwise
the germination is affected adversely. Upgrading is further done on gravity
separator if required.
packing and storage
safe storage, seeds are dried to a level of about 6% moisture and then
packed in aluminium foils or tins. Then it is stored in air conditioned
and dehumidified store having a temperature of 20-250C and
relative humidity of 30-40%. In hot and humid climate, viability of onion
seed is lost within an year. Onion seed if dried to 6.0% moisture level
and stored in sealed containers, its life may be prolonged to 3-4 years
without evident loss in seed germination.
6-8 q/ha of seed yield is obtained.If weather is favourable,it may go
upto 12 q/ha.
purpose of seed certification does not differ from other crops. It is
taken up to maintain and make available to public, through certification
high quality seed and propogating material of superior varieties so grown
and distributed to ensure genetic identity and genetic purity.Different
steps / requirements of certification are :
Inspection : For assurance of quality, the field inspections are very
much essential. The stages of inspection are mentioned below.
bulb production stage :A Minimum of two inspections should be made.
- The first
inspections should be made after transplanting of seedlings in order
to determine isolation, volunteer plants, off types including bolter
and other relevant factors.
- The second
and third inspections should be made during flowering to check isolation,
pollen shedding umbels, off types and other relevant factors.
- The fourth
inspection should be made at maturity to verify the true nature of umbels
and other relevent factors.
standards are :
Onion seed fields offered for certification should be isolated from the
contaminants by the distances.
: Contaminants and isolation distances.
distance ( m. )
Mother bulb production stage
of other varieties
of the same variety not conforming to varietal purity requirements
not conforming to varietal characteristics
permitted at second inspection at mother bulb production stage.
**Maximum permitted at and after flowering at seed production stage.
Seed Standards : Seed standards are as given below
seed ( minimum ) ( Physical )
purity ( minimum )
matter ( maximum )
crop Seeds ( maximum )
( minimum )
for vapour - proof containers (maximum)