Types of Greenhouses Based on Shape

1. Lean-to Type Greenhouse This type of greenhouse is attached to one side of an existing building. The structure utilizes the building’s wall as one of its sides, which reduces the cost of materials and simplifies the design. Generally limited in width (7 to 12 feet) and can be as long as the building it is attached to.

1. • Advantages: Utilizes existing infrastructure like electricity and water. Low-cost construction. Optimal sun exposure, especially when facing south.
   • Disadvantages: Limited space and light. Less ventilation and temperature control due to the wall’s heat retention.

2. Even Span Type Greenhouse The most common and standard greenhouse design, with symmetrical roof slopes. Suitable for medium-sized greenhouses with a clear span ranging from 5 to 9 meters.

1. • Advantages: Greater flexibility in design. Better air circulation compared to lean-to types.
   • Disadvantages: More expensive than lean-to due to greater structural needs and more glass exposure.

3. Uneven Span Type Greenhouse This design is used for hilly terrain with unequal roof slopes. Adaptable to uneven land. Disadvantages: No longer widely used due to limited automation capabilities.
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4. Ridge and Furrow Type Greenhouse

1. • Two or more A-frame greenhouses connected along the eave, forming a continuous interior space.
   • Advantages: Reduced labor and fuel consumption. Efficient for automation. Suitable for regions with heavy snow due to its sturdy design.
   • Disadvantages: Snow accumulation can be an issue.

5. Saw Tooth Type Greenhouse A variation of the ridge and furrow design with ventilation incorporated into the roof design to improve airflow.

1. • Advantages: Improved natural ventilation.
   • Disadvantages: May not be suitable for all crops depending on the ventilation requirements.

6. Quonset Greenhouse A semi-circular design with arches or trusses supporting the structure, usually covered with polyethylene plastic.

1. • Advantages: Low-cost construction, especially for small-scale operations.
   • Disadvantages: Less durable compared to glass or rigid panel designs. Limited space and flexibility for larger plants.

Types of Greenhouses Based on Utility

1. Greenhouses for Active Heating

1. • These greenhouses are designed to maintain an optimal temperature during cold weather by using various heating systems (unit heaters, radiant heat, solar heating, etc.).
   • Key Features: Double layers of polyethylene or thermo-pane glass for insulation. Efficient heat retention systems are essential to maintain the temperature inside.
   • Examples of Heating Systems:
     • Unit heaters (individual room heaters).
     • Central heating (more comprehensive for larger structures).
     • Radiant heat (floor heating systems).
     • Solar heating (using passive solar energy).

2. Greenhouses for Active Cooling

1. • Description: These greenhouses are designed to maintain cooler temperatures in hot climates, often through evaporative cooling methods.
   • Cooling Methods:
     • Evaporative cooling pad systems: Water is passed through pads, and air is drawn through them to cool the greenhouse.
     • Fog cooling: Fog is used to cool the air inside the greenhouse, increasing humidity.
   • Key Features: Roof openings of up to 40% or even 100% in some cases to allow hot air to escape and increase airflow.

Types of Greenhouses Based on Construction

1. Wooden Framed Structures

1. • Generally used for smaller greenhouses with spans less than 6 meters. The frame is primarily made of wood, such as pine or other locally available strong timber.
   • Advantages: Lower material cost. Good for small-scale or home gardening.
   • Disadvantages: Not suitable for larger spans. Less durable compared to metal frames.

2. Pipe Framed Structures

1. • These greenhouses use metal pipes for the frame. Suitable for medium-sized greenhouses (span around 12 meters).
   • Advantages: Stronger and more durable than wood. Suitable for larger structures.
   • Disadvantages: More expensive than wood. Requires proper treatment to avoid rusting.

3. Truss Framed Structures

1. • These greenhouses use complex trusses made of steel or iron, used for large greenhouses with spans of 15 meters or more.
   • Advantages: Suitable for very large greenhouses. Can support a heavy roof covering, such as glass.
   • Disadvantages: Expensive and requires more labor to install. Often more suitable for commercial scale operations.

Types of Greenhouses Based on Covering Materials

1. Glass Greenhouses

1. • Traditionally the most popular covering material, especially for high-end and commercial greenhouses.
   • Advantages: Excellent light transmission. Better air circulation.
   • Disadvantages: Expensive to build. Fragile and can break easily. Poor insulation in colder climates unless supplemented with additional heat.

2. Plastic Film Greenhouses

1. • Flexible plastics, including polyethylene, are used as covering material, making them cheaper and easier to install.
   • Advantages: Affordable, especially for small to medium-sized operations. Good insulation properties compared to glass.
   • Disadvantages: Shorter lifespan (usually around 4 years). Less light transmission as the material degrades.

3. Rigid Panel Greenhouses

1. • Polycarbonate or fiberglass panels are used, offering better durability than plastic films.
   • Advantages: Long-lasting (up to 20 years). Provides more uniform light intensity.
   • Disadvantages: More expensive than plastic films. Can become dirty, reducing light transmission over time.

4. Shading Nets

1. • Used to reduce the intensity of sunlight for sensitive plants, especially in regions with strong sunlight.
   • Advantages: Adjustable shading levels (30-90%). Protects plants from excessive heat and UV rays.
   • Disadvantages: Does not provide full protection against rain or wind. Requires proper installation and maintenance.