What is a greenhouse dehumidifier?
A greenhouse dehumidifier helps in the removal of excess water vapor from within the greenhouse air. It helps in creating a more controllable environment with higher energy efficiency. It also allows the closing of the greenhouse without the risk of an unexpected disease outbreak in the plants.
The fall and spring seasons are when humidity hits the peak and diseases that stem from excess humidity damage the plants.

How does humidity cause diseases in plants?

1. On sunny days, the transpiration from plant surfaces and evaporation from soil increases.
2. The warm air inside the greenhouse holds this moisture in vapor form
3. At night, when the air starts to cool down, condensation occurs and water droplets are formed on the cooler surface, generally the plant leaves.
4. This unwanted moisture gives room for the growth of fungal pathogens like powdery mildew.
5. Any dripping moisture from condensation on the greenhouse covering also wets the plant surface and causes the spread of pathogens from one plant to another by plant debris and splashing soil.

Benefits of dehumidification:
• Helps in maintaining optimum humidity levels for the plants to grow
• No need to compromise on ideal temperature to gain ideal humidity level
• Reduces chances of plant diseases
• Lesser need for chemical protections like pesticides
• Lesser labor costs and working hours
• Vapor pressure benefits

Tools and methods to reduce humidity levels:

1. Bottom heat- Improves air circulation and helps reduce condensation on plant leaves
2. Anti- drip plastic- using a wetting agent in the interior surface of the greenhouse to reduce humidity levels
3. Ventilation and heating- Allowing the exchange of moist greenhouse air with dry air from outside (ventilation) and to bring the outdoor air to optimum temperatures for plant growth (heating)

How to choose the right dehumidifier for the greenhouse?
There are various types, sizes and strengths od a greenhouse dehumidifier. While choosing the right dehumidifier for a greenhouse factor such as the size of the greenhouse, area that requires dehumidification, air circulation, uniformity and cost must be kept in mind. If a single dehumidifier is placed in the greenhouse with no ducting, then only the area around the dehumidifier will be dry, but areas away from the dehumidifier will definitely not be dried and will have high humidity and vapor levels. Having such a dehumidifier is pointless as the diseases outbreak will end up affecting all the plants regardless of their proximity to the dehumidifier.

What are the desirable humidity levels?
The desire humidity levels generally vary with the desired temperature. These levels are an average accepted rate and specific plants may require certain specific other levels. The most common temperatures are listed below:
• 50 Degrees Fahrenheit- 83% humidity
• 61 Degrees Fahrenheit: 89% humidity
• 68 Degrees Fahrenheit: 91% humidity
• 86 Degrees Fahrenheit: 95% humidity
Humidity management in a greenhouse is a valuable tool that helps in the prevention of fungal diseases in a plant and is a part of the overall Integrated Pest Management. Controlling the humidity inside the greenhouse along with the temperature not only reduces diseases outbreak or the use of chemical pesticides but also ensures that the reentry intervals from pesticide use does not create any issues.

What is a polyhouse?
A polyhouse refers to a structure that is specially constructed, similar to a building, for the growth of plants under controlled conditions. It is made with transparent materials, like glass or polythene, to permit the entry of natural sunlight into the built area for the plants.
Similar to greenhouses, they can be of various shapes and sizes based on the requirements of the user. Its frame is made of GI Pipes and can range anywhere between 50 Sq meters to 4000 Sq meters. Similar to a greenhouse, a polyhouse requires various heating, cooling and misting systems to maintain a conducive environment for the plants to grow in.
Crops that can be grown in a polyhouse include- Floriculture crops, Nursery plants and exotic vegetables.

Difference between polyhouse and greenhouse:
The main difference between a polyhouse and a greenhouse can be seen in the quality and build.
• A polyhouse is made out of polythene plastic as compared to a greenhouse which is made of glass or PVC.
• The materials of building make a polyhouse much more durable than a green house.
• Polythene plastic will not crack or break as easily as glass making polyhouses much more long-lasting build than greenhouses.
• Polyhouses have shown better strength in standing against natural calamities like hail, storms and hurricanes.

Benefits of polyhouse farming:
• High quality at low cost of construction
• Protection against insects and rodents
• Cost effective and low cost of maintenance as compared to traditional farming
• Plants stay clean and increase in shelf-life
• Controllable climate
• Increase in harvest quantity as lower outbreak of diseases caused by external factors.
• Off season crops can be comfortably grown
• No dependency on season changes for crop cycles to finish
• Subsidiary costs, quality and quantity advantages

How to select the right location for a polyhouse?

1. There should be enough land area to build a structure around the defined open space for the plants
2. The land should have a free flow of resources like water, electricity etc.
3. The site location should not exceed to pollution limits set by the respective government.
4. The site of construction should be higher than the surrounding land areas.
5. There should be sufficient transportation space and availability of good roads to and from the polyhouse for construction and transport of harvest.

Conditions that can be maintained in a polyhouse:
• Carbon dioxide and oxygen levels
• Temperature
• Lights
• Humidity
• Air flow and ventilation

These factors can be maintained by installing high quality misting, heating and cooling systems that will help regulating the environment of the polyhouse creating an artificial conducive place for various plants to grow freely.

Based on the control of these factors a polyhouse can be termed as:
I. Uncontrolled- Only when the top of the polyhouse is covered and all natural factors are freely available
II. Partially controlled- When a polyhouse has windows that can be opened and closed as per the requirement of the plants
III. Completely controlled- when a polyhouse does not have any windows, is completely closed and the conditions within the polyhouse are controlled remotely with advance technology and automation.

A polyhouse is extremely advantageous and a profitable investment in the agricultural sector in India. With a growing demand for exotic plants a polyhouse is the most suitable form of cultivating crops on a commercial scale.

What are greenhouse curtains?
Greenhouse curtain systems also known as greenhouse screens or greenhouse shades consist of moveable fabric or plastic films that are used to cover and uncover a greenhouse. They are used to cover either a small area of the greenhouse, that is a particular patch of certain crops or the entire greenhouse.
The movement of these greenhouse curtains can be either entirely automated (generally done for large greenhouses) or can be manually moved by hand. The main function of a curtain is to provide heat retention for the plants.

How do curtains provide heat retention for the greenhouse?
Generally, the heating demand for plants is highest at night and any greenhouse curtain can be used to meet this demand. The amount of heat retained, hence reducing fuel cost, varies based on the material of the curtain film.
Curtains can trap an insulating layer of air inside the greenhouse, reduce the volume to be heated and if the curtain has an aluminum strip, it can reflect heat back into the greenhouse.

Removal of curtain during day time:
It is extremely important to remove the curtain very slowly during the day as a curtain that is used specifically for heat retention traps the cold air between the fabric of the curtain and the roof of the greenhouse. If the curtain is opened very fast, then the cold air will drop straight on the plants, causing a sudden change in temperature and damage the plants as they wont be able to adapt to this change immediately.
To avoid this, the curtain should be uncovered gradually to allow the cold air on top to mix with the hot air already present within the greenhouse. Another option is to let the sunlight warm the cool air and then the curtain can be uncovered allowing the hot air existing inside to mix with the naturally warmed air outside. This option is however viable only if the plants can tolerate some level of shade during the day time or if artificial lighting systems are installed within the greenhouse.

Material for creating the curtains:
• Knitted white polyester
• Non- woven bonded white polyester fabric- made with alternating lines of clear and aluminum strips to reflect heat into the greenhouse.
• Composite fabric- flame resistant fabrics with gaps for air circulation

Benefits of greenhouse curtain systems:

• Helps in controlling the humidity of the greenhouse
• Heat retention during night time
• Reduces day time fluctuation of temperature
• Increases summer shading
• Cost effective compared to an artificial heating and shading system
• Can be automated completely hence reducing manual labor and labor costs
• Reduces energy consumption
• Provides conducive environment for plants even during the night time
• Day length control for exotic plants

Types of greenhouse curtain systems:

1. Gutter-to-gutter curtain system- This refers to a type of system where a single panel of fabric is used for each house. Under this system, the curtains are pulled flat across the width of the greenhouse at gutter height. Here, the volume of hot air inside the greenhouse is much lesser as compared to the volume of cold air above the curtain causing difficulty in mixing the cold and hot air when the curtain is lifted during the day time.
2. Truss-to-truss curtain system- This refers to a system where a curtain is present between each truss. When the curtains are moved, each section moves at the same time, speed and amount hence covering the area between the trusses

There are different kinds of greenhouse curtains that can be adjusted based on the needs of the plant and this is the quickest and most cost-effective method of trapping heat and provide shade to the plants within the greenhouse.

What is a greenhouse heating system?
Greenhouses create a secure and sheltered environment for plants to grow in. they trap solar radiation to increase the heat. The heating systems in a greenhouse try to create an artificial environment for plants to grow in by ensuring the temperature is hot enough for a conducive environment.
For most places, there exists at least one period of time where the climate is too cold for the specific plants to grow where the temperature outside is too low to support crop production. The heat energy provided by the heating systems can be measured in British thermal units, horsepower, calories or joules.

How is heat lost from greenhouses?
In a greenhouse, heat energy must be added to the greenhouse at the rate at which it is lost from the said greenhouse, in order to maintain the required temperature. There are 3 main ways energy is lost from a greenhouse:

1. Radiation: This refers to the loss of heat energy due to the emission of radiant energy from a warm area (the greenhouse) to a cold area (area outside the greenhouse) with very little warming of air. Compared to greenhouses made out of polythene film, glass walls of a greenhouse do not allow the passage of radiant energy.
2. Conduction: This refers to the loss of heat energy through the doors, fans, metal purlins, glazing etc. Glazing leads to a major loss of heat energy in a greenhouse and conduction is a major factor of the same.
3. Infiltration: This refers to the loss of heat energy through any cracks that may exist between and around the panels, doors and fans. No matter how tight and well designed the greenhouse is, there is always up to at least 10% of heat loss due to infiltration.

What is a greenhouse cooling system?
A greenhouse cooling system refers to a system where the greenhouse is cooled in summer or when the external temperature gets too hot and does not facilitate the growth of crops. High temperature outside the greenhouse and solar heating within the greenhouse make it essential to install a cooling system to remove hot air from inside the greenhouse.
Sometimes, when the outside temperature is appropriate, the air inside the greenhouse can simply be replaced by the air outside to maintain the required temperature. In winter, cooling may be required because of the solar input and hence the cooling systems used in summer and winter are often different from each other.

What is a greenhouse fan?
A greenhouse fan helps breaking the air stratification in the greenhouse. Since hot air is lighter than cool air, the greenhouse tends to have the hot air on top and the cold air below. A greenhouse fan helps in mixing the two temperatures of air constantly to maintain the overall temperature inside the greenhouse.

A greenhouse fan affects and improves:
• Air temperature
• Gas Concentrations (Carbon di oxide and oxygen)
• Moisture level
• Plant hardiness
• Dust and pest levels
There are various types of fans that have different purposes such as- exhaust fans, circulation fans, solar powered fans, thermostat fans, and fanjets. The right kind of fan can be chosen based on the size of the greenhouse, plant needs, outdoor climate and energy needs of the greenhouse.

What is greenhouse ventilation?
A greenhouse ventilation system replaces the stale air inside the greenhouse with fresh air. This helps in increasing the quality of plant growth and ensures that the air inside the greenhouse does not get saturated with oxygen. As light hits the walls of a greenhouse, a part of the energy absorbed is converted to heat.
While this energy can easily get into the greenhouse, it is extremely difficult for it to leave the inside of the greenhouse on its own. This energy then creates warmth which may or may not be conducive for the growth of plants. If there are no greenhouse cooling systems in place, the temperature within the greenhouse will keep rising and become extremely high that will destroy the crops.
To balance the increasing temperature in the greenhouse a proper ventilation system must be installed. The design of this ventilation system will determine the maintenance of optimal temperatures for plant growth. A good ventilation system will also help in increasing pollination of the plants and reducing the susceptibility to pests.

What is the need for greenhouse ventilation?
• Temperature control- Too much heat can cause damage to plants. There should always be a system in place that helps the heat escape at all levels.
• Humidity control- Humidity build up inside the greenhouse can also damage the plants. Water that comes off plants should be timely removed to maintain the level of humidity based on temperature.
• Air circulation- Maintaining a proper air circulation will ensure that the temperature is maintained as well as the saturation of elements in the air is combated.
• Provides carbon Dioxide- If Carbon Dioxide is not induced artificially, the ventilation system should ensure that the there is sufficient CO2 for the plants to grow and the air should not end up being oxygen saturated and hinder with the process of photosynthesis.
• Prevents pests- A good ventilation system will ensure that pests don’t multiply as it maintains temperature with low humidity. Pests require warmth and moisture to multiply and a ventilation system combats both these issues.

What are the types of greenhouse ventilation?
There are 2 main types of greenhouse ventilations and the suitability is based on factors such as the size of the greenhouse, cost of the system etc.

1. Mechanical Ventilation: This refers to a system where fans are installed inside the greenhouse to exhaust the rising hot air. This system creates a vacuum in which the cold air from outside is pulled inside through louvers on the side walls of the greenhouse. There should be various fans installed through out the greenhouse to ensure proper ventilation. When the fans are installed and operated at the right speed, they can provide the exact temperature for the plants regardless of the outside climate changes.
2. Natural Ventilation: This refers to a system where greenhouse curtains and side wall vents are used to maintain the circulation of air inside the greenhouse. A curtain system allows the movement of air across the width of the greenhouse. These systems do not require fans and are more energy and cost effective as compared to a mechanical ventilation system. They can be automated to reduce labor cost and increase operating efficiency.
   Both these ventilation system have their own pros and cons and the right kind of system should be chosen after careful consideration of all external factors that may affect the greenhouse now and on a future date.

A greenhouse heating systems refers to a process where the air inside a greenhouse is artificially heated to maintain a temperature that will promote the plant growth. These systems are definitely used in winters in places where the climate becomes too low to grow plants and is sometimes used in summer to maintain a certain level of heat energy within the greenhouse.

Types of greenhouse heating systems:
There are 2 main heating systems that can be adopted to maintain the required temperature in a greenhouse, namely, Centralized heating systems and local heating systems. The type of heating system to be chosen for the greenhouse depends on factors such as, size of the greenhouse, energy cost budgets, size of boiler units etc. Both the systems have their own benefits and can be automated to suit the needs of the owner as well as the plants inside the greenhouse.

1. Central Heating System: A central heating system is where the heat energy is generated using a large boiler in one location and is then distributes to many locations. These systems may distribute the heat energy either as hot water or steam. Most central heating systems use steel, copper or aluminum pipes to ensure that the hot water or steam is evenly distributed throughout the greenhouse.
2. Local Heating systems: A local heating system is located in the greenhouse or a section of the greenhouse that is responsible for heating. This type of heating system is often suggested for smaller operations and is much more cost effective as compared to a central heating system. There are various types of local heating systems. The main characteristic that differentiates them from other heating systems is that they are located inside the area that they are supposed to heat. Different kinds of local heating systems use different kinds of fuels.
3. Convection heaters: These heating systems are relatively low cost and are used in either commercial or domestic greenhouses. These systems use wood, agricultural waste or coal to produce heat. The fuel is burned in a large firebox and an exhaust is vented from the firebox into a large pipe that goes out to the greenhouse before being vented outside.
4. Solar heating: This system is only used in domestic greenhouses as the solar energy may not be sufficient for a commercial greenhouse. A major disadvantage of this heating method is that sunlight is not present at night and this causes a change in the internal temperature to the air of the greenhouse every single day and can drastically damage the plants.
5. Radiant heaters: This system refers to a structure of heaters where an aluminum tube with a reflector is used to combust fuel inside it. When the tube reaches a certain temperature, the tube emits infrared radiation which is directed downwards by the reflectors. The radiation is converted into heat when it strikes an surface like the plants or infrastructure in the greenhouse and ensures that the heat is hence maintained.
6. Unit heaters: This refers to a set of heaters that burn natural gas or agricultural wastes in a firebox through a supply line. The heat generated is transferred from the exhaust that is connected to the fire box, to the metal of the heat exchanger. A fan behind the unit draws the air inside the greenhouse to the heater and the heated air is transferred to the greenhouse.

As mentioned above, there are various types of heating systems that can be used to warm the air in a greenhouse. It is best to seek professional guidance to understand the exact need of the plants and determine which heating system is best suited for the same.

Why do greenhouses have different types?

There are various types of greenhouses based on the utility and functions. Out of the different utilities artificial heating and cooling systems are much more expensive and complicated. They require the help of a professional to install. The type of greenhouses is largely dependent on factors such as plants to be grown in the greenhouse, area size of the land on which the greenhouse is to be installed, cost and budgeting of the owner and other related factors.

Greenhouse types based on utility:

1. Greenhouse for active cooling: This refers to a greenhouse where the temperatures inside the greenhouse must be reduced to attain the desirable climate for the plants to grow in. This can generally be seen in summer where the external environment is too hot to promote plant growth.
2. Greenhouse for active heating: This refers to a type of greenhouse where the air temperature decreases at night or in winters. To avoid damage to the plants artificial heat should be generated based on the rate of heat energy that is lost. There are many methods that can be employed to prevent extensive heat loss such as using a double layer polyethene film or thermos pane glass panels.
   

Greenhouse types based on Covering Material:

1. Glass greenhouse: This refers to a greenhouse where glass is used as the primary material to build the walls and roof of the greenhouse. Using glass enables higher penetration of natural sunlight and higher air infiltration rates. This ensures lower humidity inside the greenhouse and helps in preventing plant disease.
2. Rigid panel greenhouse: This refers to a greenhouse that is constructed with Polyvinyl Chloride rigid panels, acrylic and polycarbonate rigid panels or fiber glass reinforced rigid panels. These panels provide a ridge and furrow type of framework to the greenhouse and the material is much more resistant to breakage as compared to glass panels. Their life is up to 20 years and they require minimum maintenance.
3. Plastic film greenhouses: This refers to a greenhouse that is constructed with plastic films that include polyethene and polyester. These materials are becoming extremely common as they are cheap and the cost of heating is relatively cheaper as compared to a glass greenhouse. However, they do not have a long life and need to be replaced every 3 to 4 years.

Greenhouse types based on construction:

1. Wooden frame structure: This refers to a greenhouse with a span less that 6 meters where wooden framed structures are used to construct the side posts and columns inside the greenhouse. Pine wood and timber wood with good strength, durability and machinability can be used for constructing these greenhouses.
2. Pipe framed structure: This refers to a greenhouse where the side posts, columns, purlins and cross ties are constructed using pipes. The area inside the greenhouse is generally around 12 meters.
3. Truss framed structure: This refers to a greenhouse where the area is generally above 15 meters and truss frames are used for the construction. A truss is made by welding together flat steel and tubular steel and encompasses chords and struts. These support support members under tension and compression respectively. Most of the glass greenhouses are of this structure.

The type of greenhouse that is suitable should be analyzed thoroughly and it is advised to seek professional help before investing in the actual structure of the greenhouse. All the different types of greenhouses have their own pros and cons which when understood thoroughly can help lead to better decision making and avoid any shortcomings in the future and ensure optimum plant growth.

Industrial Greenhouse

What is an industrial greenhouse?

An industrial greenhouse refers to a type of a greenhouse that helps in the production of plants- greens, flowers and crops that are to be sold for commercial purposes.

Types of industrial greenhouse:

Greenhouses can be classified based on their type, shape and style. The cross section of a greenhouse is what determines its width and height while the length is perpendicular to this cross section. There are 6 main types of green houses that can formed between the combination of the cross section and the length.

1. Lean-to Greenhouse:

This type of greenhouse is built when the greenhouse is placed against the side of an existing building. The existing structure is used as one side of the greenhouse which is built adjacent to it. It is generally attached next to a house and is enclosed with an extended roof made out of appropriate covering materials. These types of greenhouses are limited to 2 to 3 rows with a total width of 7 to 12 feet.

It is south-facing to ensure maximum sunlight is available for the crops. It is extremely cost effective and has easy access to electricity. With a reduced roof support structure, it gives maximum sunlight to the plants. This type of greenhouse is best for a small business or a part time industrial trade.

• Even span greenhouse:

The even span greenhouse is the standard and full-sized structure. It has 2 sloping roofs made out of glass and of equal pitch width. This design is used for small greenhouses and is constructed on a levelled ground. An even span greenhouse is also attached to a house and can accommodate 3-4 rows of plants.

An even span greenhouse is costlier than a lean- to greenhouse but has much more flexibility with designs and provides more for plants. This greenhouse will cause more heat due to the all-glass structure. A separate heating and cooling system may be required in certain cases.

• Uneven span greenhouse:

These greenhouses are generally constructed on hilly terrain. The roofs are of uneven width making the greenhouse adaptable to the hilly surroundings. The main disadvantage of this greenhouse is that very little automation is possible and hence it can not be remotely controlled.

• Ridge and furrow greenhouse:

This type of greenhouse uses multiple ‘A’ shaped frames that are connected with each other to provide one big interior for the plants. The shape of the panels provides a furrow for rain, melted snow and other liquid wastes to slide. This reduces labor, automation costs and improves personal management. Since there is less heat escaping through the walls, fuel consumption also reduces largely.

This type of greenhouse is largely suited for the Indian climate and has already show saucerful results in Europe and Canada.

• Saw tooth greenhouse:

These greenhouses are similar to ridge and furrow greenhouses with an added provision for natural ventilation. Specific natural ventilation systems can be installed based on the size and location of the greenhouse.

• Quonset greenhouse:

This refers to a greenhouse where pipe arches are supported by pipe purling running along the side of the greenhouse. Polyethene is the material generally used to cover the greenhouse. These greenhouses are generally cheaper to construct that a saw tooth or rigid and furrow greenhouse and are useful when a small isolated cultural area is required. Truss members overlap and allow a bed of crops to grow between the overlapping portions of the adjacent houses.

With the use of standard structural parts, simplified erection techniques and a modern line of production industrial greenhouses can be constructed cost-effectively and can be extremely helpful with industrial levels of farming and agriculture. Our personal one-on-one service and commitment to innovate designs provides you with the best experience of green housing

Commercial Greenhouse Construction

What is a greenhouse?

A greenhouse, also known as a glasshouse is a building with walls made of glass and a glass roof. Greenhouses are used to grow plants and flowers in an artificial setting that creates a conducive environment for their growth. Its temperature, fans, misting systems, fogging systems and cooling systems can be controlled.

Benefits of a greenhouse:

• Fresh greens, fruits and flowers all year long
• Ability to control the environment settings within the greenhouse to ensure plants grow
• Protection against droughts, winds and other natural occurrences
• Pest control and protection against animals and invasive plant species
• Ability to grow and cultivate exotic plants
• Commercial profitability compared to traditional cultivation
• Simple and cost-effective maintenance

Materials and supplies for greenhouse construction:

• Glass walls and roof
• Arches
• Canals
• Crop wires
• Support materials- wood, iron, aluminum, galvanized steel
• Plastic films and rigid plastics

What is a commercial green house?

A commercial greenhouse helps in cultivating crops for commercial use/ consumption. These greenhouses use high technology that are specifically fitted for the growth of the intended crops. These greenhouses have a transparent roof to let sunlight in or have a special lighting system to act as artificial sunlight. Heaters and coolers are used to control the greenhouse temperature. They are generally larger than domestic greenhouses and require stronger filters and systems.

How to build a commercial greenhouse?

1. Decide the location- A sunny spot that is large enough to cultivate the number of crops should be identified. The plot should not be in an extremely windy area. Even though a greenhouse is built to withstand any natural accidents, it is wise to keep the greenhouse away from such zones as much as possible.
2. Dimensions and foundations- the dimensions are based on the size of plot and the number of plants to be grown. This will further decide the types of misting, fogging and cooling systems required. The foundation will determine the right structure of the greenhouse and it is important to build a strong foundation.
3. Set up walls, sheets and roof- the walls and roof of a greenhouse are generally made of glass and allow a free flow of natural sunlight into the greenhouse to facilitate the growth of plants.
4. Finishing touches can be added in the form of aesthetic features that add to the external appearance of the greenhouse.

Automated greenhouse:

An automated greenhouse is a type of greenhouse control system that uses sensors to monitor and measure the run-off. It can control the heating, cooling, fogging and misting systems externally using sensors and monitors to control and create the right environment for the plants to grow. An automated greenhouse does not require constant monitoring of factors and is much less time consuming to maintain on a day-to-day basis.  

Cost of greenhouse construction in India:

Greenhouse cultivation has shown to be more profitable than traditional cultivation in India due to the various benefits of a greenhouse. The cost varies based on the size, features, systems and other factors involved. Its best to get in touch with the team members to get an exact quote based on all these factors.