What is Greenhouse ?
A greenhouse is a structure where plants example flowers, vegetables are produced. The temperature inside the greenhouse increases during the day by means of infiltration of the sun's beams which heat the plants, soil and structure inside the greenhouse.
Types of Greenhouses :
Greenhouse structures of different kinds are basically designed for the purpose of crop production. There is no single kind greenhouse, which can be considered as the best , all types of greenhouses have their significant advantages. Various types of greenhouse structures are intended to meet the particular requirements.
1. Greenhouse type based on shape :
Greenhouses can be classified depending on their size or style. The specificity of the cross part of the nursery for classification can be considered as a factor. As the longitudinal section would normally be equivalent for many types, the longitudinal section of the nursery cannot be used for grouping.
Cross areas illustrate the width and length of the structure and the length is opposite the plane of the cross segment. Similarly, the cross segment gives data on the general condition of the primary individuals, for example, the support or band, which will be shared again each day. The types of nursery generally dependent on size are lean-to, even span, uneven span, ridge and furrow, saw tooth and quonset type greenhouse.
a. Lean-to type greenhouse :
A lean-to design is utilized when a nursery is set against the side of a current structure like building or house. It is built against a structure, utilizing the current structure for at least one of its sides. It is typically joined to a house, yet might be connected to different structures.
The top of the structure is reached out with suitable nursery covering material and the territory is appropriately encased. It is regularly confronting the south side. The lean-to / shelter type greenhouse is restricted to single or twofold column plant seats with an all out width of 7 to 12 feet. It tends to be the length of the structure it is joined to. It should confront the best heading for satisfactory sun exposure.
⦁ The preferred position of the lean-to type greenhouse is that it is ordinarily close to accessible power, water, and warmth. It is a most economical structure. This plan utilizes daylight and limits the prerequisite of rooftop underpins.
⦁ It has some drawbacks like restricted space, restricted light, restricted ventilation and temperature control. The stature of the supporting divider restricts the possible size of the plan. Temperature control is more troublesome on the grounds that the divider that the nursery is based on, may gather the sun's warmth while the clear front of the nursery may lose heat quickly.
b. Even span type greenhouse :
The even-span is the standard sort and full-size structure , the two rooftop inclines are of equal pitch and width. This plan is used for the greenhouse of little size, and it is built on level ground. It is additional to a house at one peak end. It can oblige 2 or 3 lines of plant seats. As a result of its size and more well-known/obvious measure of uncovered glass, the even-span will cost more to warm.
The plan has a better shape over a shelter type for air courses to keep up uniform temperatures throughout the colder time of year warming season. A different warming framework is extremely important except if the structure is near a warmed structure. It will house 2 side seats, 2 walks, and a wide focus seat. A few single and different range types are for use in different places of India.
c. Uneven span type greenhouse :
Uneven span type greenhouses are built on hilly terrain. The rooftops are of inconsistent width; make the structure versatile to the side inclines of slope. This type of nursery is only occasionally utilized now-a-days as it isn't versatile for automation.
d. Ridge and furrow type greenhouse :
Plans of this sort utilize at least two A-frame greenhouses associated with each other along the length of the eave. The eave fills in as a wrinkle or canal to divert downpour and dissolved day off. The side divider is wiped out between the nurseries, which brings about a structure with a solitary enormous inside, Consolidation of inside space diminishes work, brings down the expense of computerization, improves individual administration and decreases fuel utilization as there is less uncovered divider territory through which warmth gets away.
The snow loads should be taken into the casing determinations of these nurseries since the snow can't slide off the rooftops as in the event of individual unsupported greenhouses, however it softens away. Despite snow loads, edge and wrinkle nurseries are viable in northern nations of Europe and in Canada and are appropriate to the Indian conditions.
e.) Saw tooth type Greenhouse :
Saw tooth type greenhouses are additionally like ridge and furrow type greenhouses aside from that there is arrangement for common ventilation in this sort. Explicit normal ventilation stream way creates in a saw-tooth type nursery.
f.) Quonset greenhouse :
This is, where the line curves or brackets are upheld by pipe purling running along the length of the nursery. All in all, the covering material utilized for this sort of nursery is polyethylene. Such nurseries are regularly more affordable than the canal associated nurseries and are valuable when a little confined social territory is required.
Quonset greenhouse advantages :
A quonset greenhouse is frequently arch or dome shaped, giving ideal sun infiltration is probably the best favorable position. Quonset greenhouse have systems, for example, ventilation , warming , fans and better ecological control. A preferred advantage of quonset greenhouse is that they function admirably on slopes and expand warming from the sun. One weakness or disadvantage of quonset greenhouse is that they need costly help because of lopsided or uneven design, which makes them more costly than different greenhouses. These houses are associated either in free, standing style or orchestrated in an interlocking edge and wrinkle.
2. Greenhouse Type Based On Utility :
Order of nurseries can be made relying upon the capacities or utilities. Of the various utilities, fake cooling and warming of the nursery are more costly and expound. Consequently dependent on the counterfeit cooling and warming, nurseries are delegated nurseries for dynamic warming and dynamic cooling frameworks.
a.) Greenhouses for active heating :
During the evening time, the air temperature inside the nursery diminishes. To evade the virus nibble to plants because of freezing, some measure of warmth must be provided. The prerequisites for warming a nursery rely upon the rate at which the warmth is lost to the external climate.
Different strategies are embraced to diminish the warmth misfortunes, viz., utilizing twofold layer polyethylene, thermo sheet glasses (Two layers of plant fixed glass with silence space) or to utilize warming frameworks, for example, unit radiators, focal warmth, brilliant warmth and sun oriented warming framework.
b.) Greenhouses for active cooling :
Throughout the late spring season, it is alluring to diminish the temperatures of ozone depleting substances more than the surrounding temperatures, for compelling harvest development.
Thus reasonable changes are made in the nursery so huge volumes of cooled air is brought into the nursery, This kind of nursery either comprises an evaporative cooling cushion with fan or haze cooling. This nursery is planned so that it allows a rooftop opening of 40% and now and again almost 100%.
3. Greenhouse Type Based on Construction :
The kind of development dominatingly is impacted by primary material, however the covering material likewise impacts the sort. Higher the range, more grounded ought to be the material and more underlying individuals are utilized to make durable tissues. For more modest ranges, straightforward plans like loops can be followed. So dependent on development, nurseries can be delegated :
a) Wooden framed structure :
All in all, for nurseries with ranges under 6 m, just wooden outlined structures are utilized. Side posts and segments are developed of wood without the utilization of a bracket. Pine wood 8 is normally utilized as it is modest and has the necessary strength. Wood locally accessible, with great strength, toughness and machinability likewise can be utilized for the development.
b). Pipe framed structures :
Lines are utilized for development of nurseries, when the unmistakable range is around 12 m. By and large, the side posts, segments, cross ties and purlins are developed utilizing pipes. In this sort, the supports are not utilized.
c). Truss framed structures :
In the event that the nursery range is more prominent than or equivalent to 15m, support outlines are utilized. Level steel, rounded steel or rakish iron is welded together to shape a bracket including rafters, harmonies and swaggers. Swaggers uphold individuals under pressure and harmonies uphold individuals under strain.
Point iron purlins running all through the length of the nursery are dashed to each bracket. Segments are utilized distinctly in wide support outline places of 21.3 m or more. The vast majority of the glass houses are of bracket outline type, as these edges are most appropriate for pre-creation.
4. Greenhouse based on covering materials :
Covering materials are the major and most significant piece of the nursery structure. Covering materials have an immediate impact on the nursery impact inside the structure and they change the air temperature inside the house. The kinds of casings and techniques for fixing likewise change with the covering materials , the nurseries are named glass, plastic film and unbending board nurseries.
(a). Glass greenhouses :
Just glass nurseries with glass as covering material existed before 1950. Glass is very dormant , rather than plastic and it can work for 40 to 50 years without disappointment. It is non-flammable , impervious to UV radiation and air toxin corruption, and it keeps up its underlying radiation transmission if routinely cleaned.
These nurseries have higher invasion rates which prompts less inside mugginess and better illness avoidance. What's more, the best disadvantage of glass is its weakness to calamitous misfortunes brought about by hail. Shelter type, even range, edge and wrinkle sort of plans are utilized for development of glass nurseries.
(b). Plastic Film nurseries :
Plastic (polyethylene) film is the most famous coating material , essentially because of its low beginning expense. It is genuinely reasonable to introduce, requiring generally restricted measures of other primary material, particularly when utilized in a Quonset – style development.
One of its points of interest is that it is an incredible diffuser of daylight, taking into account serious light at the shelter level of the nursery. It is an incredible decision for first time nursery producers. Perhaps the greatest downside to utilize plastic film is it has a genuinely short life expectancy. Over the long haul daylight and air contamination significantly debilitates polyethylene and makes it weak making it shred and tear.
c). Rigid panel greenhouses :
Polyvinyl chloride inflexible boards, fiberglass-fortified plastic ,acrylic and polycarbonate unbending boards are utilized as the covering material in the Quonset type outlines or unbending and wrinkle type outline. This material is more impervious to breakage and the light power is uniform all through the nursery when contrasted with glass or plastic.
High evaluation boards have a long life even upto 20 years .The fundamental inconvenience is that these boards will in general gather dust just as to 5 harbor, which bring about obscuring of boards and resulting decrease in the light transmission . There is a critical threat of fire peril.
d). Shading nets :
There are an incredible number of types and assortments of plants that fill normally in the most different atmosphere conditions that have been moved by present day horticulture from their common territories to controlled harvest conditions. Consequently, conditions like the normal ones should be made for each sort and assortment of plant.
Each sort of developed plant should be given the particular kind of shade needed for the different periods of its turn of events. The concealing nets satisfy the undertaking of giving proper miniature atmosphere conditions to the plants.
Shade meshes are intended to shield the harvests and plants from UV radiation, however they additionally give insurance from atmosphere conditions, for example, temperature variety, concentrated downpour and winds. Better development conditions can be accomplished for the harvest because of the controlled miniature atmosphere conditions "made" in the covered zone, with conceal netting, which brings about higher harvest yields.
All meshes are UV balanced out to satisfy anticipated lifetime at the zone of openness. They are described by high tear obstruction, low weight for simple and speedy establishment with a 30-90% shade esteem range. A wide scope of concealing nets are accessible in the market which are characterized based on the level of shade they convey to the plant developing under them.
Advantages of Greenhouses :
- Longer Growing Season.
- Climate Protection.
- Bug / Pest Prevention.
- Convenience and Customization.
- More Plant Options.
- New greens, vegetables and organic products.
- New cut flowers throughout the year.
- A warm spot to go in a chilly, dim winter.
- Capacity to produce plants you wouldn't in any case have the option to produce.
- No more fights with squirrels and bugs.
Disadvantages of Greenhouses :
- Can be costly to construct.
- Fertilization Problems in Greenhouses.
- Temperature and Ventilation Management.
- Can be costly to warm.
- Requires consistent checking, support and care.
- Could expand electrical and water bills.
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