Advantages of greenhouse cultivation

Advantages of Greenhouse Farming:
Increased production per unit area (in other words, up to ten times higher than open-field cultivation). For example, in the case of cucumber, production in a greenhouse can reach about 20 kilograms per square meter, compared to only 2 kilograms per square meter in open-field conditions.
Production of more than one crop per year, such as three production cycles per year for cucumber and two production cycles per year for tomato.
Improved quality of the produced crops, achieved through better and more precise control of pests and diseases using biological control methods, reduced use of chemical pesticides, higher product quality, increased export potential, and environmental protection.
Water conservation, particularly through the use of pressurized irrigation systems.
Utilization of non-arable lands through hydroponic systems (such as greenhouse vegetable production in Kish Island).
Independence of production from environmental conditions, enabling effective marketing and scheduling of cultivation programs according to market demand (for example, scheduling cucumber harvest for late March).
Continuous operation and year-round production, due to the ability to control environmental factors and regulate conditions required by plants.
Creation of suitable employment opportunities for young people and agricultural graduates, as well as productive use of farmers’ free time during autumn and winter seasons.
What Should Be Done When Deciding on Greenhouse Cultivation?
Identifying the target market (“sell your crop before planting”); it must be clear where the product will be sold.
Determining different periods of the year in terms of sales volume, market stagnation and saturation, and periods of shortage and high market demand.
Selecting the type and characteristics of the required product based on consumer preferences in the target region (for example, producing small or large tomatoes, yellow or black peppers, etc.).
Collecting meteorological data for the cultivation area (ten-year averages of minimum temperature on the coldest night of the year, maximum temperature on the hottest day, average annual rainfall, number of sunny days, cloudy days, frost days, etc.).
Determining geographical orientation and prevailing wind directions in the region.
Evaluating soil characteristics, including texture, structure, soil pH, soil EC, macro- and micronutrients, lime content, cation exchange capacity, and related factors.
Assessing water quantity and quality in the region; approximately one cubic meter of water per square meter of greenhouse soil bed should be available, and dissolved solids such as sodium bicarbonate, chlorine, and fluoride should be within acceptable limits.
Distance between the greenhouse and the consumer market.
Labor wages in the region where the greenhouse will be established.
Collecting scientific information related to planting, cultivation, harvesting, pests, diseases, and storage of the intended crop.
Visiting nearby greenhouses to gather scientific and practical information in order to avoid repeating others’ mistakes.
Different Types of Greenhouses
Single-Slope Greenhouse:
A single-slope greenhouse is usually built adjacent to a wall. The northern wall is constructed of solid materials, while the eastern and western walls are either fully or partially made of brick. The southern wall is shorter than the northern wall and faces south. The roof slope angle with the ground ranges from 30 to 55 degrees, depending on latitude. In the Northern Hemisphere, the farther one moves from the equator, the steeper the roof slope should be; conversely, closer to the equator, the roof angle should be smaller. Maximum light utilization occurs when sunlight strikes the greenhouse surface perpendicularly, minimizing reflection. Therefore, as one moves toward the poles, solar rays become more oblique.
Uneven-Span (Asymmetrical) Greenhouse:
This type is similar to a double-span greenhouse, but the roof consists of two unequal slopes. The roof slope angle ranges from 35 to 55 degrees. This design allows optimal light utilization and minimizes roof area. In regions with low winter light intensity, uneven-span greenhouses are constructed so that the southern surface receives more light than the northern surface. If the southern roof forms a 25-degree angle with the horizontal plane and the northern roof a 55-degree angle, about 11 percent more light is received through the covering. If the southern roof angle is 90 degrees and the northern roof angle is 65 degrees, even more light is received. In such cases, the northern wall can be fitted with reflective insulating materials, increasing light availability for plants and reducing heat loss.
A-Shaped Greenhouse:
In this type of greenhouse, the two roof sides are of equal width. The height at the highest point of the roof ranges from 2.5 to 3.5 meters, and the width ranges from 3 to 6 meters. The roof slope angle is between 35 and 55 degrees.
Quonset (Semi-Cylindrical) Greenhouse:
The framework is constructed from water pipes bent into 180-degree arches (pipe diameters range from 1.88 to 2.5 centimeters). These arches are supported by purlins running along the length of the greenhouse. The distance between main arches is about 4.5 meters, and the spacing between purlins ranges from 0.9 to 1.2 meters.
Furrow and Ridge or Gutter-Connected Greenhouse:
In this type of greenhouse, the walls between adjacent greenhouse units are removed, resulting in reduced structural requirements.