![Mist Chamber
• Propagation by cuttings [rooting of cuttings]
• In Mist Chamber, Relative humidity is maintained artificially at high level (95 %) with
the help of mist installations, which spray water under pressure.](https://image.slidesharecdn.com/plantpropagationstructures-240725163400-3d7ac481/85/Plant-Propagation-Structures-45-320.jpg)
![Manure heated hot beds
• South and south eastern exposures - are
preferable because beds will get more
sunshine
• Frames: wood, cement, brick or stone
[concrete - best]
• Frames may extent 30-45cm above the
surface of the ground on backside and 15-
30 cm in the front, thus giving a slope
• For every one mere, across bar or a slide
should be placed for the sash to rest upon](https://image.slidesharecdn.com/plantpropagationstructures-240725163400-3d7ac481/85/Plant-Propagation-Structures-50-320.jpg)
Plant Propagation Structures
- 1. PLANT PROPAGATION STRUCTURES Dr. S.ANANDHI Assistant Professor (Horticulture) SRM College of Agricultural Sciences Chengalpattu
- 2. Propagation structures • Structures which facilitate propagation of plants • Required for propagating plants by seed, cuttings and grafting Types • The first type a structure with temperature control and ample light, where seeds can be germinated or cuttings are rooted or tissues culture micro-plants are rooted and acclimatized Eg: Green house, poly house or hot bed • The second unit is a structure into which the younger, tender plants can be moved for hardening, preparatory to transplanting out-of-doors. Eg: Cold frames, low polyethylene tunnels or sun tunnels covered by saran cloth and lath-houses.
- 3. Green house • A greenhouse is a framed, inflated structure covered with a transparent material in which crops can be grown under at least partially controlled environment. • A greenhouse is large enough to permit people to work within it and to carry out cultural operations.
- 4. How does a greenhouse work? • Every greenhouse operates on a simple physical principle called "the greenhouse effect". • Sunlight passes through transparent or translucent materials such as glass or plastic. When it strikes an opaque surface inside (plant leaves, greenhouse floor, planters) some of the light energy is changed into heat. • The darker the surface, the more heat is generated. The greenhouse panels are good at transmitting light, but not heat. Therefore, most of the heat stays inside.
- 5. • Orientation • Single greenhouses with latitude above 40°N should have ridge running east to west to allow low angle light to enter from side rather than ends. • Below 40°N the ridge of single greenhouses should be oriented from north to south, since the angle of sun is much higher. This orientation permits the movement of shadow of the gutter across the green house. • Size of the greenhouse The dimension of GH should not be more than 50m x 50m. • Spacing between greenhouses The spacing between naturally ventilated green house should be 10 to 15 m so that the exhaust from one greenhouse should not enter the adjacent greenhouse. • Height of greenhouse The maximum height can be up to 5m for 50m x 50m green house and this can be reduced as per the reduced size of the green house.
- 7. COMPONENTS OF GREENHOUSE 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. • 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 • 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 multispan 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
- 15. • Types of green house - Classification as per type of structure
- 17. Types of Greenhouses lean to uneven-span even-span ridge-and-furrow
- 19. Classification based on number of spans a. Free standing or single span b. Multispan or ridge and furrow or gutter connected
- 21. Even span gutter connected greenhouse
- 22. Gutter connected Green house
- 23. Classification as per glazing or covering material or cladding material • Glass • Flexible covering materials - polyethylene, UV-stabilized polythene • Rigid covering materials - acrylic, polycarbonate and fibre glass
- 24. Glass covered greenhouses are • expensive but for a permanent long term installation under low light winter conditions because glass has superior light transmitting properties • and less excessive relative humidity problems
- 25. • Polyethylene materials are light weight and relatively less expensive compared to glass. • Being light in weight, permits a less expensive supportive frame work than is required for glass. • Polyethylene has relatively short life than glass. • The UV-stabilized sheets can last for 3-4 years. • Polyethylene having a thickness of 100-200 micron is generally used.
- 26. • For providing rigid panels fiber glass is used widely for construction of greenhouse. • It transmits 80-90% of light.
- 27. • The acrylic is highly weather resistant and does not yellow with age, has excellent light transmission properties and retains twice the heat of glass, but it is more costly and brittle.
- 28. Polycarbonate: • It is probably, the most widely used structures sheet material today. • This material is similar to acrylic in heat retention properties, with 90% light transmission of glass. • It is light in weight 1/6th of glass and easy to install. • Polycarbonate textured surface diffuses light and reduces condensation drip.
- 29. S. No. Type Durability Transmission Maintenance Light Heat 1. Poly ethylene One year 90% 70% Very high 2. Poly ethylene UV resistant Two years 90% 70% High 3. Fiber Glass Seven years 90% 5% Low 4. Tedlar coated Fiber Glass Fifteen years 90% 5% Low 5. Double strength Glass Fifty years 90% 5% Low 6. Poly carbonate Fifty years 90% 5% Very low Comparison of different kinds of covering materials
- 30. Greenhouse type based on construction a) Wooden framed structure b) Pipe framed structure c) Truss framed structure Wooden framing
- 33. Aluminium framed Green house
- 34. Classification based on environmental control a) Naturally ventilated polyhouse These polyhouse do not have any environmental control system except for the provision of adequate ventilation and fogger system to prevent basically the damage from weather aberrations and other natural agents. b) Environmental controlled polyhouse This type of polyhouse helps to extend the growing season or permits off- season production by way of controlling light, temperature, humidity, carbon- dioxide level and nature of root medium.
- 35. Classification of greenhouse based on suitability and cost a) Low cost or low tech greenhouse • Low cost greenhouse is a simple structure constructed with locally available materials such as bamboo, timber etc. • The ultra violet (UV) film is used as cladding materials. • Unlike conventional or hi-tech greenhouses, no specific control device for regulating environmental parameters inside the greenhouse are provided. • Simple techniques are, however, adopted for increasing or decreasing the temperature and humidity. • Even light intensity can be reduced by incorporating shading materials like nets. • The temperature can be reduced during summer by opening the side walls. Such structure is used as rain shelter for crop cultivation. • Otherwise, inside temperature is increased when all sidewalls are covered with plastic film. This type of greenhouse is mainly suitable for cold climatic zone.
- 36. Medium-tech greenhouse • Greenhouse users prefers to have manually or semiautomatic control arrangement owing to minimum investment. • This type of greenhouse is constructed using galvanized iron (G.I) pipes. • Evaporative cooling pads and misting arrangements are also made to maintain a favourable humidity inside the greenhouse. • As these system are semi-automatic, hence, require a lot of attention and care, and it is very difficult and cumbersome to maintain uniform environment throughout the cropping period. • These greenhouses are suitable for dry and composite climatic zones.
- 37. • Hi-tech greenhouse To overcome some of the difficulties in medium-tech greenhouse, a hi-tech greenhouse where the entire device, controlling the environment parameters, are supported to function automatically. Liquid CO2 tank Natural gas CO2 generators Computerized Environmental Control Systems Optimum CO2 for crop yield: 1000- 2000 ppm
- 38. FAN AND PAD SYSTEM
- 40. Heating methods • Hot water heaters • Forced air heaters • Stem heat • Solar energy
- 43. Co2 enrichment in green house • To sustain the rate of the plant growth. • To increase the rate of plant growth. • To eliminate pests such as whiteflies and spider mites because at very high concentrations carbon dioxide is toxic to animal life. • To substantially increase yields.
- 44. Cost involved 1. Less expensive greenhouse without fan and pad Rs.300 to 500/m2 2. Medium cost greenhouse with pad and fan system Rs.800 to Rs.1100/m2 without automation 3. Expensive greenhouses with fully automatic Rs.2000 to Rs.3500/m2 control system
- 45. Mist Chamber • Propagation by cuttings [rooting of cuttings] • In Mist Chamber, Relative humidity is maintained artificially at high level (95 %) with the help of mist installations, which spray water under pressure.
- 46. The aim of misting is to maintain humidity by a continuous film of water on the leaves, thus reducing transpiration and keeping the cutting turgid until rooting take place. Mist propagation units are used for propagation of “difficult to root, cutting in most advanced countries.
- 47. Mist Chamber A fine mist is sprayed intermittently over the cutting at regular intervals during day and night. The mist unit is controlled by a time clock, operating a magnetic solenoid valve and is set in a way to turn on the mist for 3-5 seconds to wet the leaves and turn off for some time and when the leaves are dry. The mist is again turned on. The water should have good pressure and it must be free from salts. The optimum pH of water to be used in mist unit is 5.5 to 6.5.
- 48. Mist has 5 control mechanisms • The two types of timers are used in a mist unit, one turn on in the morning and off at night and the second operate during day hours to produce an intermittent mist, usually 6 seconds “on” and 90 seconds “off”. • In electronic leaf, a plastic with two terminals is placed under the mist along with cuttings, the alternate drying and wetting of the terminal breaks of the current, which in turn control the solenoid valve. • A thermostat controls the temperature of the mist. • In screen balance control mechanisms, stainless steel screen in attached to a lever with mercury switch. When mist is on, water is collected on the screen and when weight of water is more, it trips the mercury switch. • The photoelectric controls are based on the relationship between light intensity and transpiration rate.
- 49. HOTBEDS • 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. • Hotbeds are used for forcing plants or for raising early seedlings. • Instead of relying on outside sources of supply for seedlings, you 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.
- 50. Manure heated hot beds • South and south eastern exposures - are preferable because beds will get more sunshine • Frames: wood, cement, brick or stone [concrete - best] • Frames may extent 30-45cm above the surface of the ground on backside and 15- 30 cm in the front, thus giving a slope • For every one mere, across bar or a slide should be placed for the sash to rest upon
- 52. Lath house/ Shadenet house • A framed structure made of materials such as GI pipes, angle iron, wood or bamboo. • It is covered with plastics net (Nets are made of 100% Polyethylene thread with specialised UV treatment) having different shade percentages. • It provides partially controlled atmosphere and environment by reducing light intensity and effective heat during day time to crops grown under it.
- 53. • Shadenets are available in different shade percentages or shade factor i.e 15%, 35%, 40%, 50% 75% and 90% (for example 35% shade factor means - the net will cut 35% of light intensity and would allow only 65% of light intensity to pass through the net).
- 54. Type of Shadenets • Presently shadenets are available in different colours i.e. white, black, red, blue, yellow and green and in combinations: • Green x Black - cut off un-wanted U.V rays and gives aesthetic look. Used in grape for providing shade and helps in drying. • Black x Black - it absorbs and radiates heat inside the shadenet house. Used in nursery raising. • White x Black - diffuses the light inside the shadenet house. Mainly used for flowers such as Gerbera, Anthurium etc. • Green x Green - enhance the process of photosynthesis in plants resulting better foliage in ornamental plants.
- 55. COLD FRAMES • A cold frame is a bottomless box with a removable top. • It is used to protect small plants from wind and low temperatures. • No artificial heat or manure is used inside a true cold frame but many gardeners experiment with a variety of soil conditions. • They utilize the sun's heat. • The soil inside the box is heated during the day and gives off its heat at night to keep the plants warm. • Low-cost cold frame construction is the same as for hot beds, except that no provision is made for supplying bottom heat.
- 56. Polytunnels • Also known as a polyhouse, hoop greenhouse or hoop house, grow tunnel or high tunnel • A tunnel typically made from steel and covered in polythene, usually semi-circular, square or elongated in shape • The interior heats up because incoming solar radiation from the sun warms plants, soil, and other things inside the building faster than heat can escape the structure. • Air warmed by the heat from hot interior surfaces is retained in the building by the roof and wall.
- 57. Plastic Tunnels Plastic Tunnels Used in Nursery
- 58. Plastic Tunnels/poly 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.
- 59. •A phytotron is an enclosed research greenhouse used for studying interactions between plants and the environment. •Phytotron is a facility where a number of Growth Chambers and Greenhouses are organized in such a way that different environmental factors can be simulated for research studies simultaneously. PHYTOTRON
- 60. •National Phytotron Facility is available at IARI, New Delhi. •This is the first facility of its kind Greenhouse Gases in the country to study the live responses of plants under controlled conditions and the possible impact of climate change and greenhouse gases.
- 61. THANK YOU