Earth’s shape and orbit around the sun are a bliss for a few regions and a bane for others. Owing to the proximity to the sun, few geographical places experience abundant sunlight. The vegetation in this region thrives naturally without dependence on greenhouse glazing systems. Other regions are not so lucky as the experience has harsh winters and sub-tropical and sub-zero climates. Plants need sunlight to photosynthesize food from water and carbon dioxide. If the temperature is hot, the stomata opens wide to absorb the sunlight. During winter plants conserve energy, and their metabolic activity is lowest.
Regions that experience extreme hot and cold weather are not ideal for agricultural practices. Growing food is an uphill task in these places. In the last few years, extensive use of commercial greenhouse farming has been witnessed to overcome the food crisis and reduce the cost of importing food. Open-air farming in cold countries is very limited, reducing the harvest cycle of the crops. Contrarily, greenhouses help in controlling the climate inside the space, by trapping the heat and sunlight, thereby extending the harvest cycle of the crops. With technology, maintaining a constant temperature throughout the year is easy and simple. It translates to round-the-year crop yields leading to abundance. However, the functional aspect of greenhouses largely depends on the material used in the structure. Depending on the regional requirements and the budget constraints one has to choose the glazing material for the greenhouse. Let us look at the various available options:
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Glass
Glass is a classical choice for many as it offers the best transparency and aesthetic value. Since it has high transparency, it also has high transmission of photosynthetically active radiation. The retention of the heat during night times is higher, and extra insulation is not required. Transmission of UV light is very low in glass greenhouses. The glass available in current times is more durable and can withstand a few Christmases without issues. The cost of using glass is on the higher side. However, over the years the benefits outweigh the initial investment.
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Plastic Sheets
Materials such as polycarbonate, acrylic, and fiberglass are used as glazing materials. These materials are budget-friendly and are more durable than plastic films. In comparison to glass, although these materials are less transparent, their photosynthetic active radiation levels are decent. However, in sub-zero temperatures, extra insulation is recommended to retain the heat and light. Across the world, these materials are gaining popularity in greenhouse construction.
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Plastic Films
It is the least expensive glazing material where polyethylene or PVCs are used as thin films to protect the plants from excessive cold winds. Coupled with a shade net, plastic films are used for nursery beds, even in hot countries. Till plants are a few weeks old and ready to be transplanted, they are nurtured, in polyhouses.
Conclusion:
Now every region can locally produce food without depending on other nations. Choosing the glazing material depends on the geographical zone, budget, and farming requirements.
