One of important stages of construction of the greenhouse is the choice of ukryvny material. Correctly picked up covering provides not only esthetics of exterior of design, but also creation of the favorable microclimate directly affecting productivity of plants.
At construction of the greenhouse it is important to remember that the quality of harvest directly depends on quantity of the sunlight getting through walls and ceiling of hotbed. Therefore the covering has to ensure good transparency, safety of heat and possibility of fast removal of pollution of surface. The film, glass and polycarbonate are considered as the most widespread ukryvny hothouse materials.
Advantages polyethylene and PVC of film consist in its low cost, availability, ease of mounting and good ability to pass and to evenly scatter sunlight. Such material ideally keeps heat, and svetopreobrazuyushchy colored films are capable to transform ultraviolet to the infrared radiation protecting plants from overheating, burns and accelerating their growth.
The fragility, need for prewinter dismantling from greenhouse framework, vozdukho- and water tightness are considered as essential shortcomings of film coverings. Accumulation of condensate on inside face of such covering quite often leads to sticking of dust and dirt that causes various diseases of hothouse plants.
Glass is considered traditional covering for greenhouses. It well passes light and accumulates heat, does not require specialized care, maintains washing by means of abrasive materials and does not spoil when processing plants toxic chemicals. The important advantage of glass is also its chemical inertness: at strong heating by sunshine glass, unlike film PVC, does not allocate in air of hazardous substances and does not exude specific smell. However mounting of glass greenhouses is very difficult, demands availability of reinforced frame and skills of work with fragile materials. In addition, glass – expensive material that will negatively affect the budget in case of emergency replacements of elements of glazing. In hot days the glass design strongly heats up that not always does well to plants and therefore such greenhouses need regular airing in the afternoon. At night, if cool weather was established, glass will quickly give the saved-up heat and it is necessary to think over the system of additional heating of air. Greenhouses from cellular polycarbonate are tamperproof, have the increased durability and durability. Sheets of polycarbonate flexible and elastic that provides ease of mounting and possibility of use of household, nonprofessional tools for work with tree or metal. Plastic panels well pass and scatter light, reliably keep heat, are unpretentious in service. From polycarbonate it is possible to refer need of the device of system of aeration or mounting of special window leaves, processing of panels to covering shortcomings sealant for protection of hundreds against hit in them of moisture that reduces transparency of the greenhouse because of water "blossoming". Besides, some inexpensive panels in which production the salvage has been used are capable to emit at strong heating in air hazardous substances.