- №1. Advantages and disadvantages of the greenhouse film
- №2. Main types of films for greenhouses
- No. 3. Polyethylene film
- №4. Reinforced film
- №5. PVC film for greenhouses
- №6. Polyethylene films with special additives
- №7. Density and thickness of the film
- №8. Color of the film
- №9. Manufacturers of film
Until recently, the film was the most popular material for the arrangement of greenhouses. Today, it is replaced by glass and polycarbonate, which surpass it in many ways, but do not have a low price. If the budget is limited, it is possible to grow a crop in a greenhouse, covered with a film, but it still needs to be able to choose.Film foil strife: manufacturers offer both the simplest polyethylene, and more practical options, such as reinforced, PVC and stabilized. Vendors also strive to issue cheap material for a more expensive analog, becauseoutwardly some species are very similar. How in these conditions to choose a film for a greenhouse, not to overpay and to be assured of its quality?
№1. Advantages and disadvantages of the greenhouse film
Previously, for the hiding of greenhouses used only polyethylene film. At the moment, gardeners are offered more perfect analogues, in which some shortcomings are less pronounced. In general, for all types of films that are used for the arrangement of greenhouses and greenhouses, are characteristicgeneral pros and cons.
- low price. Between the different types of film there are differences in price, but compared to glass and polycarbonate it is still a budget option;
- high elasticity and plasticity, therefore with the help of a film it is possible to equip a greenhouse of any shape;
- water resistance;
- high light transmittance and the ability to diffuse sunlight;
- low weight and easy installation.
- low durability. Choosing polyethylene film, it is worth to be ready, that for the next season it will need to be changed. More expensive analogues will have to be changed in 2-3 seasons;
- low resistance to sunlight, which leads to rapid destruction of the material, but in some films this defect is not so pronounced;
- Condensate accumulates on the surface of the film, which harms the majority of crops grown in the heifer. This disadvantage was avoided by hydrophilic films, in the production of which special additives are used;
- accumulation of electrostatic charge, which contributes to attracting dust, and this, in turn, reduces transparency. With this minus, manufacturers are also trying to fight by introducing special supplements.
Many gardeners also complain that the film is stretched and sagging, so you have to constantly pull it up. But the presence of so many significant disadvantages still does not make the material less popular, because itthe cheapest way to equip a greenhouseat the dacha, and many believe that it is more profitable to change coverage once a year than to immediately spend money on buying expensive polycarbonate.
№2. Main types of films for greenhouses
All the variety of films for greenhouses can be divided into these types:
- polyethylene (the most common and inexpensive);
- polyvinyl chloride;
- films with additives (light stabilizing, antistatic, thermostabilizing, foamed and others).
No. 3. Polyethylene film
The main advantage -low cost. The film transmits about 80% of the thermal radiation, so daytime heat is poorly maintained at night. Correctly mounted quality polyethylene film will lastno more than a season, and winter is unlikely to survive, as temperature changes, wind and snow will destroy the material. Even the thickest films do not differ in special longevity.
Polyethylene filmvery soft, therefore it is necessary to transport and mount it very carefully. Even the smallest cut will soon "expand which will bring to nothing all efforts to equip the greenhouse.
Sell the material in rolls with a width of -3 m, this can be a single-layer fabric or sleeve. In the second case, the material can be cut at the seam and get a wider canvas, or you can cover the hothouse with a sleeve, although you should not count on a significant increase in longevity. The bend of the sleeve is considered the weakest point and is destroyed in the first place, so it is better to immediately fix it with adhesive tape.
№4. Reinforced film
Reinforced film differs from conventional polyethylene by the presence of a uniquecarcass, made of fiberglass, pressed, twisted or stretched polyethylene or polypropylene, the thickness of the carcass filaments, 9 2 mm. Polyethylene, as a rule, is used more durable, sometimes with additives for greater resistance to sunlight. The main load is taken over by the frame, so the greenhouse with such a coating gets resistance to winds, snow and even a degree. The film can protect seedlings even with frosts down to -50 ° C.
The material will last on the greenhouse for more than a year, it usually sufficesfor three seasons, but some manufacturers talk about the service life of 5 and even 7 years, but much depends on the characteristics of the film and the climatic conditions of the region. Reinforced filmmore maintainable: holes can be sealed with adhesive tape, they do not have the property to extend to the entire canvas. The main characteristic of the material is not its thickness, but its density. The most common is a material with a density of 120-200 g / m2. On sale there is a film with holes in the cells, which provides the greenhouse proper tightness, but it does not allow "conserve" air in it.
The durability and strength of the reinforced film turns out to be morehigh price. In addition, the light transmittance of this material is slightly lower than that of a conventional stabilized film, and the dust is washed off due to the relief, which also damages the transparency.
№5. PVC film for greenhouses
Polyvinyl chloride films - one of the best options for the arrangement of greenhouses. It is an elastic and durable material that can hold outfrom 2-3 seasonsup to 6-7 depending on operating conditions, care and climate. As a rule, light-converting and stabilizing additives are introduced into the composition.
Material skipsup to 90% of light, 80% of ultraviolet radiationand delays up to 95% of infrared radiation, which means that at night and during frosts in the hotbed will be warmer than in the same of the polyethylene film. This is a very significant advantage of the material.
Lack of material - the price, which is 2-3 times higher than the cost of a polyethylene equivalent, but taking into account the fact, that there is no need for every season to buy a new film and mount it, this minus can not be called too much essential. Another nuance - polyvinyl chloride stronglyattracts dust, but it is not difficult to flush it. Frost resistance of the material is low, at temperatures below -150С the film becomes too fragile, therefore for winter greenhouses heating will be mandatory.
№6. Polyethylene films with special additives
If you introduce specific substances into polyethylene, you can slightly improve its performance.Depending on the additives, the following types of material are distinguished:
- stabilized filmis made with the addition of substances that increaseresistance to sunlight. The service life rises by 2-3 times, and the price also increases. The material may have an orange or pinkish tinge, but this is not necessary. Externally, the stabilized and conventional polyethylene film is the same, so you should carefully look at the packaging and labeling;
- light-converting film"Is able" to transform a hard ultraviolet, harmful to plants, into infrared and red radiation, which increase yield. All this is possible due to the phosphor additive, but in order for the material to last for a long time, it is necessary that the composition also contain stabilizing substances. To make sure that you really have a light-converting film, you need to shine with an ultraviolet lamp, while the light from the lamp should change to red;
- heat-retaining filmdiffers a matte whitish shade. It weakly transmits thermal radiation, so the temperature in the greenhouse will be 1-30C higher than in the similar of other types of film. Due to this, the early harvests can be increased by 10-30%, saving on heating. The lifetime of the film is about 9 months, the material has antistatic and hydrophilic properties;
- stabilized hydrophilic filmallows to solve the problem of "drop characteristic for other types of material. This film forms a flat-drop condensate in the form of a continuous layer, so there is no negative effect on plants. The high transmittance is high, the ability to transmit thermal radiation is 30-35%, so there will be heat in such greenhouses;
- bubble wrapstrongly resembles the one that packs fragile goods. It has good light transmission, and the level of thermal insulation will compare with polycarbonate. Strength is low, except for special types of film, but for the cultivation of early harvests in a small greenhouse material will come in handy;
- foamed filmconsists of a monolithic and foamed polyethylene layer, transmits 70% of light, holds heat well, is suitable for the construction of greenhouses intended for vegetative propagation of plants;
- copolymer ethylene vinyl acetateIt has a decent level of strength, good heat retention, it is resistant to punctures, wind loads, frost, hydrophilic. High light transmittance (up to 92%) on hot summer days can cause overheating. Durability - up to 3 years;
- photodestructive filmis destroyed after a certain period (20, 45 and 60 days). It is used for frameless shelters and mulching.
Despite the stated lifespan, some experts recommend changing the film every three years, as it is still cloudy. If the material has preserved its integrity, it can be used for other purposes.
You can also find films, in the production of which several additives were used at once - this is the best option. But often under the guise of special films are given the usual polyethylene, so do not interferelook at the certificates and labeling.
According to GOST 10354-82, stabilized film for greenhouses and greenhouses are labeled ST, stabilized light-converting film - SIC. Also for greenhouses, you can use a film marked with the letter H: it is a stabilized or unstabilized film for the manufacture of household products.
№7. Density and thickness of the film
The thicker and thicker the film, the better it will cope with the negative environmental factors. In the case of a conventional polyethylene film, thickness has little effect on durability, and when it comes to stabilized materials this factor is of greater importance.
Externally, a film with a thickness of 200 and 100 μm is impossible to distinguish, which is used by unscrupulous sellers. To protect yourself from unprofitable purchases, it is worth remembering that a thicker film weighs more:the film's running meter 200 μm weighs 530 grams, 150 μm - 400 g, 120 μm - 320 g,100 microns - 260 gramsand 80 microns - 210 g. For greenhouses it is better to choose a film with a thickness of 150-200 microns.
№8. Color of the film
It is better to choose a transparent film- she misses more light. To obtain a material of different shades, the food color is usually introduced into the formulation, which has the property of being burned under the sun's rays, so there is no point in it. If the paint is stable, light will penetrate into the greenhouse less, which will result in lower yields and the need for additional lighting.
№9. Manufacturers of film
If the choice is stopped on a conventional polyethylene film, then the risk of running into a substandard product is reduced. More fakes occur in the category of more expensive types of films: for example, for a stabilized film can give out the usual. In any case, it is better to trust the proven manufacturers, it is good to look at the accompanying documentation and marking.
The film of such manufacturers possesses sufficient quality:
- SPF "Shar"- a company from St. Petersburg, founded in 1991 and specializing in the development of composite polymer materials. For agriculture produce films of different types, including. "Svetlitsa "Rostok" and "Yuzhanka" use their own development, all materials are durable, and "Svetlitsa according to the manufacturer, serves up to 7 years;
- "Agro-farm"- one of the leading domestic enterprises in the field of polymer production. The range of the manufacturer is the widest, and Vural Plastik film with reinforcement is produced for greenhouses;
- «Agrothema A»- a domestic enterprise that has been operating since 1993. The main activity is the production of polyethylene film for various spheres of use. For the equipment of greenhouses the usual polyethylene and reinforced film is offered;
- "Stable"- a company that produces film under the trademark Stabilen. When it is manufactured, Fitistab's patented unique additive is used to obtain A durable material suitable for year-round use in virtually all climates belts. Several types of films are produced, differing in thickness and basic properties, all have the highest quality, are exported to the countries of the near abroad;
- "Odysseus"works since 2005, specializes in the production of polyethylene. For greenhouses, conventional polyethylene and reinforced films of different thickness and width are produced;
- "Polymer"- Kemerovo plant with 30 years of experience in the production of films. Greenhouse films of the company are considered one of the best among domestic, their range is the broadest, constantly replenished with new types;
- "ORA"- St. Petersburg company, equipped with modern imported equipment and producing a variety of film brands, including. "Polisvetan" and "Antipresen". The quality is high, the price is affordable;
- Richel Serres de France- a French company that offers integrated solutions for the arrangement of greenhouses. The official dealer for us is the company "Greenhouse Technologies which offers the film Richel. She, according to reviews, keeps even on winter greenhouses long enough.
Despite the fact that the film - not the most durable and durable material for creating greenhouses, with literate approach to its choice will be at a minimum cost to equip the greenhouse by all the rules and get good yields.