Plant propagation structures in plant nursery

1. Introduction
• Plant propagation structures plays vital role in propagation of
various seedlings and grafts in nurseries.
• These structures helps to maintain congenial climatic conditions
for better germination, easy rooting and hardening of seedling.
• Plant propagation structures helps the successful and healthy
production of seedlings.
Plant Propagation Structures in Nursery:
 Green House
 Poly-houses
 Glass Houses
 Net houses
 Plastic tunnels
 Mist Chambers
 Hot Beds
 Cold Frames
 Humidifiers

2. Green House
• Greenhouses are frames of inflated structure covered with a transparent
material in which crops are grown under controlled environment
conditions.
• Greenhouse cultivation as well as other modes of controlled environment
cultivation have been evolved to create favorable micro-climates, which
favours the crop production could be possible all through the year or part
of the year as required.
• Greenhouses and other technologies for controlled environment plant
production are associated with the off-season production of ornamentals
and foods of high value in cold climate areas where outdoor production is
not possible.
• The primary environmental parameter traditionally controlled is
temperature, usually providing heat to overcome extreme cold conditions.
• However, environmental control can also include cooling to mitigate
excessive temperatures, light control either shading or adding
supplemental light, carbon dioxide levels, relative humidity, water, plant
nutrients and pest control.

3. Classification Of Green Houses
 Classification as per type of structure
a. Quonset type
b. Curved roof type
c. Gable roof type
 Classification as per glazing
a. Glass glazing
b. Fiberglass reinforced plastic glazing
i. Plain sheet
ii. Corrugated sheet
c. Plastic film
i. Ultra violet stabilized low density poly ethylene
ii. Silpaulin
 Classification based on number of spans
a. Free standing or single span
b. Multispan or ridge and furrow or gutter connected
 Classification based on environmental control
a. Naturally ventilated
b. Passive ventilation

4. Components of greenhouse
Roof: transparent cover of a green house.
Gable: transparent wall of a green house
Cladding material: transparent material mounted on the walls and
roof of a green house.
Rigid cladding material: cladding material with such a degree of
rigidity that any deformation of the structure may result in damage
to it. Ex. Glass
Flexible cladding material: cladding material with such a degree of
flexibility that any deformation of the structure will not result in
damage to it. Ex. Plastic film
Gutter: collects and drains rain water and snow which is place at an
elevated level between two spans.
Column: vertical structure member carrying the green house
structure

5. • Purlin: a member who connects cladding supporting bars to the
columns
• Ridge: highest horizontal section in top of the roof
• Girder: horizontal structure member, connecting columns on gutter
height
• Bracings: To support the structure against wind
• Arches: Member supporting covering materials
• Foundation pipe: Connection between the structure and ground
• Span width: Center to center distance of the gutters in multi-span
houses
• Green house length: dimension of the green house in the direction
of gable
• Green house width: dimension of the green house in the direction
of the gutter

6. Green Houses

7. Plant growing structures / containers in
greenhouse production
• The duration of crop in greenhouse is the key to make the greenhouse
technology profitable or the duration of production in greenhouses should
be short. In this context, use of containers in greenhouse production
assumes greater significance. The containers are used for the following
activities in greenhouse production. • Raising of seedlings in the nursery
• Growing plants in greenhouses for hybrid seed production of flowers
• Growing plants for cutflower production.
• Growing potted ornamental plants.
• Advantages of containers in greenhouse production
• Increase in production capacity by reducing crop time.
• High quality of the greenhouse product
• Uniformity in plant growth with good vigour.
• Provide quick take off with little or no transplanting shock.
• Easy maintenance of sanitation in greenhouse
• Easy to handle, grade and shift or for transportation.
• Better water drainage and aeration in pot media.
• Easy to monitor chemical characteristics and plant nutrition with
advanced irrigation systems like drips.

8. Advantage of Green house:
Under greenhouse one can grow crops under controlled environment
and throughout the year four to five crops can be grown due to the
availability of required plant environmental conditions.
This helps in increased crop productivity and superior quality of
produce can be obtained.
Gadgets for efficient use of various inputs like water, fertilizer,
seeds and plant protection chemicals can be well maintained in a
green house.
Pasts and disease can be effectively controlled in the growing
enclosed area.
Percentage of germination of seeds is high in greenhouse.
When the crops are not grown, drying and related operation of the
harvested produce can be taken up utilizing the entrapped heat.
Greenhouses are suitable for automation of irrigation, application of
other inputs and environmental control by using computer and
artificial intelligence techniques.
Self-employment for educated youth on farm can be increased.

9. Poly-house
• Poly-house is widely used for prorogating off season seedlings
which fetch better price in the market.
• Modern poly-house are automated for temperature and humidity
control to assist propagation
• In poly-houses, plant are propagated using pro-trays or poly-
bags on ground or benches.
• In Poly-houses, thermostat, hygrometer, automatic ventilation
system is maintained to facilitate micro-climate.
• Irrigation and fertigation systems in poly-houses is automated
to provide measured quantity of water and nutrients to plants.

10. Poly-house Structure for Nursery Net house Structure for Nursery
Polyhouse

11. Net House
• Net houses are widely used as propagation structure in tropical
areas, where artificial heating is not required and artificial
cooling is expensive.
• The roof of net house may be covered with gunny cloth or even
with live plant creeper to cut off the solar radiation and to keep
the house cool. Different type of shade nets are available in the
market for shade purpose.
• Net houses can be constructed as per need of propagation and
therefore its size of net houses varies.

12. Plastic Tunnels
• Plastic tunnel is a simple but effective method of protective
cultivation, used by many nurserymen throughout the world.
• The three feet wide loops which support the polyethylene are
made from 0.2 inch diameter wire and are erected at 30 inches
intervals.
• A white translucent polyethylene sheet of 6 feet wide is then
stretched over the loops and is fastened to the frame of the
tunnel.
• Plastic tunnels prove effective for seed germination as well as
vegetative propagation of nursery plants in winter season.

13. Plastic Tunnels
Plastic Tunnels Used in Nursery

14. Glass Houses
Roof and all the four sides of glass houses are covered with glass
sheets.
Green house effect increases temperature inside glass houses.
Most of the glass houses are provided with heating systems.
During summer, cooling devices are also provided.
Temperature, humidity, light and carbon dioxide are also controlled
through computerized micro processor system for providing ideal
conditions.
CO2 enrichment is done inside the glass house for increasing yield.
Plants are fed with optimum amount of nutrients through drip
irrigation and foliar spray.
The high initial outlay for erection of glass houses and for providing
glass house environment is compensated by long duration,
prolonged harvesting periods, high yield and good quality.

15. Mist Chamber
• Nursery plants propagated by cuttings are grown in mist
chambers.
• In Mist Chamber, Relative humidity is maintained artificially at
high level (95 %) with the help of mist installations, which
spray water under pressure.
• High relative humidity facilitate better root initiation and
cooling effect prevents the cutting from drying out.

16. Mist Chamber
Mist Chamber Used in Nursery

17. Advantages
• This method results in faster rooting of the cuttings.
• Create optimum Microclimate for better root initiation and
development.
• Higher success rate found in propagation of hard wood
cuttings.
Disadvantages
• Hardening of rooted cuttings is more difficult and requires
careful attention. Selection of right medium is very important.
• Under mist conditions oxygen deficiency can create problem.
Mist Chamber

18. Hot Beds A hotbed is a bed of soil enclosed in a
glass or plastic frame. It is heated by
manure, electricity, steam, or hot-
water pipes.
The frame of hot bed made of
concrete blocks which acts as an
effective insulator but obstruct light.
Reinforced polyester plastic is also
used for frame. It is light in weight,
easy to handle and admits light,
which however, is likely to decrease
with age.
Hot beds are headed with the help of
different heating systems like hot air,
hot water and electricity, which are
adopted depending upon availability
and cost, systems.

19. • Hotbeds are used for forcing plants or for raising early seedlings.
• Instead of relying on outside sources of supply for seedlings, we can
grow vegetables and flowers best suited to your own garden.
• Seeds may be started in a heated bed weeks or months before they
can be sown out of doors.
• At the proper time the hotbeds can be converted into a cold frame
for hardening.
• The plants may then be moved to the garden when outdoor
conditions are favourable.
• The hotbed should be located on well drained soil. In some
locations a 3-inch layer of gravel under the prepared soil mixture or
under flats may be required.
• For supplementary heating, electric soil-heating tape or cable with
a thermostat to automatically control temperature and make more
efficient use of electricity is suggested.

20. Cold Frame The cold frame is made with frame
and the cover.
Cold frames are used to protect plants
from frosts heavy rains and heavy
winds.
These are used in winter for raising
herbaceous leafy vegetable plants.
During summer, cover may be
removed.
Cold frames are of two types (i)
temporary which is usually made of
wood, and (ii) permanent which is
made of concrete, concrete block and
bricks.
A cold frame is a bottomless box with
a removable top. It is used to protect
small plants from wind and low
temperatures.

21. • With a cold frame, we can do many of the same things as in a
greenhouse.
• We can sow summer flowers and vegetables weeks before outdoor
planting. So we will gain sufficient time to grow an extra crop.
• We can start vegetables, annual flowers for fall and winter, and
perennials for next year's bloom.
• Plants are protected from harsh weather and will grow to
transplant size quickly.
• We can root cuttings of deciduous and evergreen shrubs and trees,
softwood cuttings of chrysanthemums, geraniums, and fuchsia,
and leaf cuttings of Bryophyllum.
• African violets and succulent and foliage plants take root faster in
a cold-frame, particularly during warmer months.
• We can also grow lettuce, chives, endives, parsley, and green
onions right through the winter by converting to a hotbed.

22. Cold frames and Hot beds
• Cold frames and hotbeds are mini-greenhouses in that both use
solar energy for a source of heat and light. The main difference
between cold frames and hotbeds is that hotbeds have a
supplemental heat source.
• Uses-Cold frames and hotbeds can be used to:
• increase the length of growing season by starting plants earlier and
providing protection for some plants in the fall.
• overwinter semi-hardy plants.
• start transplants.
• harden off plants.
• dry fruits, vegetables, and flowers.
• force flowering bulbs.
• start root cuttings.
• stratify seeds, nuts and acorns.
• vernalize plant material.

23. Humidifiers
• A humidifier is a device that increases moisture in a single room or
an entire building. In the home, point-of-use humidifiers are
commonly used to humidify a single room, while whole-house or
furnace humidifiers, which connect to a home, provide humidity to
the entire house.
Role of Humidifiers in Propagation:
• Overhead fogging maintained greenhouse humidity above its
set point and avoided excessively low humidity conditions on
sunny days.
• Managing humidification for greenhouse propagation can be a
critical step to ensure healthier plants and greater yield from
the crop.

24. • The main purpose for adding humidity for greenhouse
propagation is to create an environment where plants will
thrive. This capability will promote increased health and
productivity within the greenhouse by eliminating ‘plant
water stress’.
• Greenhouse cooling systems (humidification systems)
facilitate seedling development and healthy plant growth by
generating high volumes of ultra-fine droplets that evaporate
quickly.
• In hot, arid climates, grow successfully through the summer
months with the maximum cooling potential. In colder
climates, maintain optimal humidity to maintain nutrient
uptake and plant health through the heating season.
• Control the propagation of young plants and seedlings by
maintaining constant humidity levels. The correct
environment allows faster and more even rooting for
maximum output.