Forcing Techniques For Raising Summer Vegetables

2. Introduction:-
• Forcing techniques are used to grow
vegetables in artificial growing conditions.
• In these techniques vegetables are grown out
of their normal growing season in net houses,
green houses, glass houses and other artificial
structures that admit light and induce favorable
environmental conditions.
• These techniques can also be used sometimes
to prolong the growing season.

3. Salient features of forcing
techniques:-
 The cost incurred in production of crops is
higher than other available methods.
 Different structure are required to facilitate
these techniques like green house, cold frames,
low tunnels etc.
 It is the most intensive method of cultivation

4. .
 Additional technical know how is required in
the usage of these techniques.
 techniques provide artificial environment to
the crops.
These are the type of specialized demand
oriented programme. Few vegetable crops such
as tomatoes, cucumbers, capsicum etc are
grown in this type of farming.
 ‘Tunnel farming’ is one of the most followed
method of forcing techniques.

5. A Typical Example :-
According to Choudary (1997) , in the winter
season growing of summer crops on the river
beds with the help of organic manures, with
breaks of dry grass is also the type of forcing
technique.
Some times for early product seedlings of crops
like tomato or brinjal are forced to germinate
in small protected structures. This may also be
the type of vegetable forcing.

6. Advantages of Vegetable
Forcing:-
1) Better facilities with which to start early stages early
vegetables plants for outdoor culture; probably 90% of
our greenhouse vegetable growers are also market
gardeners or truckers.
2) The possibility of keeping in touch with one’s patrons
between the summer seasons.
3) The ability to give employment during the winter to
the most satisfactory employees.
4) The increased pleasure of rural life during the winter
by creating summer conditions on a small part of the
farm.

7. Types of Vegetable Forcing :-
I. By the use of manure-heated hotbeds. This is the
oldest type used in the United states, and it is still
practiced to some extent by commercial growers. Its
chief value, however, is for the farmer and village
gardener who desires a continuous supply of fresh
vegetables for their own tables.
II. By the growing of crops on a large commercial scale
in frames heated by steam or hot water, or merely
covered with glass or protecting cloth. This type of
forcing is especially important in southern gardening
districts.

8. .
III. By the growing of vegetables for the home
table by the people who can afford to operate
greenhouses solely on their land.
IV. Mulching:- The covering of surface around
plants makes a condition more conductive for
growth through moisture conservation, better
co2 control exchange for roots system and
soil moisture management.

9. .
• V. Low and Walking tunnel:- Row covers or
low tunnel are flexible transparent covering
that are installed over rows or individual beds
of transplanted vegetables to enhance plant
growth by warming the air around the plants in
open field during winter season.

10. .
VI. Naturally ventilated greenhouses:- these are
the protected structures where no heating or
cooling devices are provided for climate
control. Light intensity can be reduced by
incorporating shading material like nets.
.

11. .
VII. Semi-Climate controlled greenhouses:-
These are constructed over galvanized iron
pipes exhaust fans with thermostat are
provided to control the temperature.
Evaporative cooling pads and misting
arrangement are also made to maintain
favourable humidity

12. .
VIII. Climate Controlled greenhouse:- This type
of greenhouse is constructed to achieve higher
degree of climate control to enhance the
cultivation period of the crops. Evaporative
cooling and the heaters are used to maintain
the required temperature inside greenhouse
spaces as and when required. The greenhouse
consists of a sensor, a comparator, and an
operator.
These green mostly used for the cultivation of
parthenocarpic cucumber, cherry , tomato and
coloured sweet pepper.

13. .
• .

14. .
IX. Net house Cultivation:- Vegetables are
produced with minimum use of pesticides. It is
a framed structure consisting GI pipes covered
with UV stabilized net of 40 mesh size to
control entry of flying insects. PAU has a so
far recommended the early cultivation of
capsicum, tomato and brinjal in the net house
without risk of vectors.

15. Production through micro-irrigation
and Fertigation
This system is very useful in saving irrigation
water, fertilizers and improving the quality of
vegetables. The system is mandatory in high
tech vegetable production.

16. Soil less cultivation
This method has increased significantly due to
the use of methyl bromide as a soil disinfectant
between crops cycles or will be banned soon.

17. Hydroponics
In this system plants are grown in nutrients and
water solution without soil. Terrestrial may be
grown with their roots in the mineral solution
only or in an inter medium, such as perlite or
gravel .

18. Aeroponics
Plants are grown in troughs, tubes or other type
of chambers and roots are hung in air sprayed
with nutrient mist. So, it easily absorbs
nutrients and oxygen. This technique has less
chance of root disease.

19. Nursery Raising in Plug trays:-
Growers have made the transition to green house
grown transplants using various type of
containers, Primarily plug trays.

20. .
 For raising nursery of vegetables in plug trays,
commonly used soil less media in coco peat,
vermiculite, perlite which is mixed in 3:1:1
ratio on volume basis.
 The size and volume of cells pro-trays also
have been standardized for different vegetable
crops.

21. Forcing techniques used in different
summer vegetables:-
Capsicum:-
• Nursery of crop is sown in first fortnight of
October. Protect the seedlings against whitefly to
check the spread of viruses.
• Cover them with agro-net of 40 mesh size. 4-5
weeks old seedlings are planted on both sides of
raised beds.
• In December fix the iron arches manually at a
distance of 2 metre so as to cover the rows .
Transparent plastic sheets should be used to cover
the plants.

22. .
• The sides of sheets should be buried in the soil
when temperature rise in February remove the
plastic sheets.

23. .
Cucumber:- The beds of 2.5 meter width are
prepared in the month of December. The
sowing is done on the both sides of bed at
45cm . Cover the cucumber crop under low
poly tunnel like capsicum. When temperature
rises in February remove the plastic sheets.

24. .
Recently, parthenocarpic cucumber variety “
Punjab Kheera-1” has been recommended for
poly net house cultivation.
Fruits of this variety are dark green, seedless,
bitter free, medium size(125gm) , 13-15cm
long and do not require peeling.
Its average yield is 304q/acre and 370q/acre in
September and January sown crops,
respectively.

25. .
Brinjal:-
Low plastic tunnel technology is
recommended to protect the plant during
winter.
Seedlings are transplanted in November on
raised beds at spacing of 90 X 30 cm. In first
week of December iron arches are fixed and
covered with transparent non perforated plastic
sheets.
When temperature rises remove the plastic
sheets.

26. .
Recommended varieties
• PBHR-41 has a yield of 376q/acre.
• PBHR-42 has a yield of 360q/acre.

27. .
Tomato:-
The indeterminate varieties of tomato are suitable
under net houses which continue to grow in set
fruit throughout their life cycle.
• Treat the seeds with 3g captan per kg of seed
before sowing and sowing should be done in beds
in end of September.
• After 20-25 days of transplanting, earthing is to
be done. Staking is necessary, plants must be
pruned and fruit thinned throughout the crop
cycle.
• Harvesting of fruits start in end of February and
continue till May.

28. .
Recommended varieties are :-
1. Punjab Swarna
2. Punjab Gaurav
3. Punjab Sartaj
4. Punjab Red Cherry
5. Punjab Sona Cherry
6. Punjab Kesar Cherry.

29. Major Constraints in Forcing
Techniques
• Cost effective design of green houses suitable for
different climate needs to be standardized.
• The package of practices including fertigation
needs to be worked out.
• Pest and disease management is crucial as it
provides favourable conditions for their
proliferation.
• intensive cultivation in green house give rise to
growth and development of numerous pathogens
including nematods.

30. CONCLUSION:-
• Effective and eco-friendly control measures to
be evolved.
• Development of suitable varieties for forcing
techniques requires an immediate attention and
effort to reduce dependence on imported seeds.
• PAU has already developed varieties in
different crops for cultivation under forcing
techniques.

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