Thickness and varieties of greenhouse films, film repair
Treat greenhouse films with care
It is known that in our climatic conditions it is impossible to grow a good harvest of heat-loving crops (tomatoes, cucumbers, peppers, eggplants, etc.) without covering them with a film. Unfortunately, many summer residents and gardeners buy either unreliable films, but cheap, or durable and expensive, but poorly conducive to the harvest.
Since the choice of film is a delicate matter, the author considered it necessary to show the main factors that reduce the durability of films. The main ones are:
Thickness and thickness difference of films
Experience shows that such films are less durable if they have a small thickness and a large difference in thickness. Most often, the market offers customers a film with a thickness of 0.100; 0.120 and 0.150 mm, and with an increase in thickness, its price increases. The same is observed with the difference in thickness, which, according to my experience, can be from 0.01 to 0.015 mm. From this it is clear that a thin and different thickness film will serve a shorter period. This means that it is best not to skimp, pay more, but choose a thicker film. Thanks to this, it will last three seasons instead of one with a minimum thickness.
Frame material for film
Most summer residents and gardeners do not take this factor into account at all. Meanwhile, according to experimental data, on a rough unpainted frame or rusty metal, the film intensively loses its elasticity, becomes brittle, fragile and quickly collapses. The actual elongation at break in such cases reaches less than 100%. If the wood is planed, the metal is not rusted, and both materials are painted white, then the elongation at break of the film is 250-350%. All this indicates that with a smooth frame, the film, deforming and rubbing on it, can serve not 1, but 2-3 seasons.
The indicator that determines the level of light nutrition of plants, and hence the yield of cultivated crops, is the transmission of photoactive radiation, which reaches 85-90% for stabilized, hydrophilic and PVC films, which last for an average of three years. Many years of experience helped me make a choice: I prefer a hydrophilic film, which, although expensive, excludes drops of concentrated moisture from getting on the plants, preventing the likelihood of their disease. In addition, this film provides a minimum transmittance of infrared radiation (35%), turning the coating into a kind of trap for radiant energy. A version of the stabilized film has also appeared on the market. It is pinkish due to the pigment in it, does not fade, gives an enhanced orange-red spectrum of light, favorable for plants. I have been using one of these films for two years now, while there are no complaints about its quality.
Securing the film
The rupture of the film, perhaps even more often than from the reasons already mentioned above, occurs from errors when it is fixed on the frame. If you look closely at various greenhouses and greenhouses in the areas, you can find that often the film is attached with nails, and even without washers, because of which it often comes off and gradually breaks into pieces. The film must be fixed to wooden structures not directly with nails, but with the use of slats and glazing beads, which tightly press it to the frame. If the frame is metal, then a rail is first attached to it, to which the film is nailed, pressing it with wooden slats. When the film is laid on the arcs of the bed, it is usually recommended to simply cover its lower edge with earth. However, this method is unreliable and worsens the conditions for the care of plants. In practice, more and more often, a strip of dense material with loops is attached to this edge of the panel, and a board or pegs with nails for the loops are installed on the ground. At the same time, to access the plants or ventilate the greenhouse, it is enough just to remove the hinges from the nails.
As practice shows, even a very good film, subject to all the above conditions, after three years of operation, ceases to serve due to aging, thickness variation and careless handling. However, based on personal experience and the experience of other summer residents and gardeners, I can say that the durability of the film can be extended for another 1-2 seasons due to its repair. Today, experienced gardeners usually use five methods of repairing films. It:
- stitching the edges with threads, for which the pieces are connected with strips of thick paper between them, while the lines are made rare;
- melting of the edges to be joined, for which they are clamped between two smooth metal plates, and the parts of the panels protruding outward by 1 cm are exposed to either a blowtorch or a spirit lamp;
- welding, in which the edges of the panels are superimposed on each other, covered with paper or even newspaper, and carried out at the junction with an iron or a soldering iron;
- gluing the damaged edges of the panel with glue, for which the patches from the film are smeared with glue, for example, PVA brands and quickly applied to the damaged areas, and the glue quickly sets;
- gluing the edges of damaged areas of the film with adhesive tape such as adhesive tape, available on the market.
From my own experience I know that well-repaired films can still successfully serve, if not for their intended purpose, then in a new way. The experience of using them during frosts is especially successful as a second layer of shelter for a greenhouse, greenhouse or garden bed, as well as when the ground is cold before sowing or planting, and it must be heated.
It is very important to take good care of your films after the end of the summer season. It is advisable to wash all films from adhering earth and dirt, dry, and then roll up and store indoors.
In conclusion, I would like to note that all the described recommendations for choosing films and methods for storing and repairing them will undoubtedly not only help to get good yields of heat-loving crops, but also significantly save your money.
Anatoly Veselov, gardener
How to choose plastic wrap for a greenhouse and greenhouse - a critical review of all types
Several years ago, it was believed that plastic film for greenhouses is less attractive than glass and polycarbonate, as it is short-lived and inferior in quality. But the chemical industry does not stand still.
Knowing the disadvantages of conventional polyethylene, manufacturing plants are developing new formulas and methods to eliminate them.
Thus, various chemical additives appear in the composition of modern PE films, the structure of the material itself, its characteristics and properties change.
Physical and mechanical properties of greenhouse film
Polyethylene is widely used in agriculture. The fact that it is recyclable by all known high-throughput techniques makes it even more valuable. This polymer has a number of properties that have made it the leader in greenhouse coating materials.
The disadvantages, which are also present, are compensated by the low price of film materials.
Film in greenhouses perfectly replaces fragile glass
Advantages of plastic wrap as a coating
The film coating has many advantages, some of which typical summer residents do not even know about.
- Ease. Covering a greenhouse with PE-film does not require a strong frame, as is the case with glass or polycarbonate. The installation of the material is carried out manually, without special construction machinery and equipment. It is also easy to transport - it is sold in rolls in the form of a canvas, a sleeve or a half-sleeve with or without a fold.
- Transparency. Greenhouse film transmits a sufficient amount of light waves in the visible spectrum, and it transmits UV rays even better than glass.
- Resistant to weather conditions. A greenhouse with a new polyethylene cover is a fairly solid construction. It withstands not only gusts of wind and heavy rainfall, but also small hail and even the weight of the snow that has fallen. In addition, the temperature range at which the material does not lose its properties is wide - from -50 ° C in winter to 50 ° C in hot summer.
- Moisture retention. The greenhouse maintains optimum air humidity due to the "greenhouse effect". At the same time, the plants are not waterlogged and are not flooded with prolonged precipitation or melting snow.
- Environmental friendliness. Polyethylene is biologically neutral, it does not affect plants, soil, water and air in any way, does not emit toxic fumes. The fact that under natural conditions the film decomposes for a very long time is compensated by the ease of processing at any specialized plant.
- Price. The cost of this polymer is quite low. It is considered the most affordable type of greenhouse cover.
Polyethylene has a good level of transparency
The main disadvantages of film material
Considering the film as a cover for the greenhouse, one cannot but pay attention to the shortcomings.
- Fragility. This is the most obvious drawback of greenhouse plastic sheeting. The material is destroyed under the influence of ultraviolet radiation - the sun's rays. Manufacturers are developing new types of polyethylene to extend the service life.
- Lack of strength. Despite the fact that polyethylene withstands weather tests well, damage such as punctures and cuts will instantly render it unusable.
- Droplet formation. Condensation, which forms as a result of evaporation of moisture from the soil, settles on the film and falls in drops. Such constant exposure negatively affects the condition of the plants. For some types of polyethylene, this problem has already been solved.
- Electrostatic charge builds up. Simply put, the coating becomes electrified and dust adheres to it. As a result, light transmission is lost - the main characteristic of the greenhouse.
- Elasticity. Elasticity is considered an advantage in other applications of polyethylene. But when constructing a greenhouse, this characteristic only interferes. Sometimes the film bends even under its own weight. Under the influence of precipitation, the coating stretches even more and sags until it fails completely.
Greenhouse covering material in a roll
Varieties of polyethylene covering material
There are several types of greenhouse plastic films, which differ from each other in the amount and quality of chemical impurities, structure and physical properties. Each of them provides different conditions for the greenhouse. The main varieties are:
- unstabilized polyethylene film
- light stabilized greenhouse film
- stabilized hydrophilic PE film
Unstabilized polyethylene - budget option
Unstabilized film is the easiest and cheapest option for a home greenhouse. The yield under such a film is not the highest. This is because the coating transmits infrared radiation (heat) from the greenhouse. Thus, about 80% of the heat is lost overnight. The temperature difference outside and inside the greenhouse is not high.
Small home greenhouse
The service life of unstabilized film is 7-8 months. This is enough to get one harvest, but the next year the cover will have to be completely changed.
Light stabilized - protection for several years
If you plan to use the coating for several seasons, then it is better to opt for a light stabilized greenhouse film. Outwardly, it differs from ordinary polyethylene in a yellowish tint. Includes UV stabilizer. This additive can significantly extend the life of the coating.
The function of UV stabilizers is to refract direct sunlight. This has a beneficial effect not only on the film, but also on plants, which also suffer from excess ultraviolet radiation.
Durable stabilized polyethylene
Technologists have developed special formulations that can increase the service life for a given time. A light stabilized film is available with a lifespan of one, two or three years.
The term of operation means the time during which the film retains its properties by at least 50%. This indicator is very relative and average.
In practice, everything depends on the location of the greenhouse, the average annual temperature, the amount of precipitation, and even on the design of the greenhouse.
Stabilized hydrophilic anti-drip film
The stabilized hydrophilic film is the next step in the development of greenhouse coatings. Retaining all the advantages of conventional and light-stabilized polyethylene, manufacturers have overcome another greenhouse problem - condensation drops. The daily temperature difference is the reason that moisture accumulates on the surface in the morning. Cold water droplets can kill young shoots.
Water flows down the natural slope of the walls of the covering and does not drip down onto the plants. There is another indirect advantage of droplet condensate. It is an additional layer and reduces heat loss.
When folded, the film is very compact
Reinforced film - for strength and durability
Achieving the durability of a greenhouse cover is easy. It is enough to use a reinforced polyethylene film as a covering material. For its manufacture, stabilized polyethylene is used.
A net of fine threads is applied to the base. Reinforcement is most often made of low pressure polyethylene. In some cases, polyamide and even fiberglass can be used.
Due to this reinforcement, the film becomes tensile strength several times.
Antistatic additives are often added to the composition. They protect the surface from dust. Dust significantly reduces the characteristics of the greenhouse, since the surface loses its transparency and transmits less sunlight.
Reinforced polyethylene fibers
Heat-retaining polyethylene - for heat-loving plants
For early planting of thermophilic plants, it is advisable to use additional heating of the greenhouse. To avoid unnecessary costs, you can use a special coating - heat-retaining polyethylene. Such a film can be distinguished by its characteristic matte shade.
In terms of its light transmission qualities, this type of coating is not inferior to a stabilized film. It can also contain antistatic agents and anti-fog agents to combat dust and condensation. However, heat-retaining greenhouse film transmits significantly less infrared rays. This is its effect.
The heat accumulated during the day does not leave the greenhouse at night. The temperature inside a greenhouse with a heat-retaining coating is 2 degrees higher on average.
Heat retention properties are provided by the matte surface of the film
Three layers - maximum efficiency
Greenhouse plastic wrap manufacturers have been able to combine all the benefits of the most common varieties in one. This revolutionary technology simultaneously solves all the problems associated with the use of film material. The secret lies in the use of three thin layers of polyethylene. Each layer contains different additives and has a different function.
The outer thin layer contains absorbent, which is part of the heat-retaining film. It protects the greenhouse from heat loss. Antifogger is added to the inner layer to combat condensation drops. The thickest layer is the middle one. It ensures the strength of the material. It is impossible to see all three layers with the naked eye. Three-layer greenhouse film looks like a uniform canvas.
Multilayer film is stronger and more reliable
Bubble wrap - not just for packaging
Another unusual type of greenhouse covering material is bubble wrap. As it turned out, it can be used not only as packaging. Bubble polyethylene is an excellent thermal insulation material.
The air gap that is present inside each bubble protects the plants in the greenhouse from frost. If one bubble is damaged, the others will not be affected. This is the undoubted advantage of the cellular structure.
The bubble wrap consists of two layers. But some manufacturers use an additional protective layer of polyethylene on the outside. The optimum web thickness is 150 microns. With this thickness, the ideal balance of strength and light transmission is maintained.
Black film for greenhouses
Black polyethylene film for greenhouses stands apart from greenhouse film materials. This material is not used to cover the frames, it is used directly on the beds as mulch and for a number of other tasks. Polyethylene helps:
Application of black polyethylene for mulching
It can be difficult to decide which film for a greenhouse is better, but professionals with extensive experience in building and maintaining greenhouses will help.
Features of the
Film for greenhouses has many features that make the product the most popular among summer residents and owners of suburban areas. The material has a high wind load of 34 m / s. The greenhouse film can be used at temperatures from –50 to +60 degrees. The light transmittance index is 77%. These distinctive features make the product virtually universal.
Polyethylene is fused with fiberglass mesh, which increases the strength of the products. If you make a hole in the film, it will not creep, and the degree of damage will be minimal. Some canvases contain special fasteners with a rubber ring. When choosing such products, you do not need to make cuts.
Reinforced canvas has a complex composition, which consists of three layers. The first level is a reinforced frame, the rest of the layers are presented in the form of light stabilizing fabrics. The entire load is distributed over the fiberglass mesh. Due to this structure, the products are distinguished by a high degree of strength.
The disadvantage of the reinforced material is the low level of light transmission. It is 12% lower than that of traditional film.
Previously, only polyethylene sheets were used for greenhouses. At the moment, the market for greenhouse products is developing and improved analogues are offered to summer residents that have less pronounced disadvantages. However, all types of films have identical advantages and disadvantages.
Greenhouse film has the following advantages:
- affordable cost. Each type has its own price category, but if we compare it with glass or polycarbonate products, the film remains the most budgetary option.
- high level of elasticity and plasticity. Thanks to these qualities, you can create greenhouses of any shape.
- moisture resistance
- high light transmission, along with the ability to diffuse sunlight
- light weight
- easy installation.
The main disadvantages include the following nuances:
- short service life. When choosing a plastic wrap, you should be prepared for the fact that the purchase of a new product will be required for the next season. More expensive items last for 2-3 seasons
- low degree of resistance to sun rays. This leads to rapid wear of the film. In some cases, this indicator is not so pronounced.
- Condensation forms on the surface of the material, which can harm many crops. This defect can be eliminated with the help of a hydrophilic film, which is made with the addition of special components.
- the ability to accumulate electrostatic charge leads to the attraction of dust, which reduces the transparency of the material. Manufacturers are trying to deal with the disadvantage by adding special components.
From many summer residents, you can hear that the greenhouse canvas is subject to sagging and stretching, so it must be constantly tightened. However, the presence of such negative characteristics does not reduce the popularity of the material.
Film is the cheapest product for arranging greenhouses, so many agree that it is more profitable to replace the coating once a year than to buy expensive material right away.
There are several varieties of greenhouse film that you should familiarize yourself with before purchasing. Each of the types has its own characteristics and characteristics, on the basis of which each summer resident will be able to make the right choice. There are zipper types that are easy to use.
Polyethylene sheets for greenhouses are sold in rolls. You can buy products with a width of 1.2 to 3 meters. There are options from one layer and two-layer, the sleeve of which is cut along the fold line.
When cutting a polyethylene sleeve, you will need to tape the fold with tape to extend the life of the material.
The best option for a greenhouse is products with a thickness of 0.1 mm to 0.15 mm. Thicker options have a long service life, but will not work for next year.
Polyethylene film is considered the cheapest and most popular material, but when it comes into contact with atmospheric phenomena, it quickly wears out and loses all its characteristics. Such a purchase would be the best option for arranging a small greenhouse in a summer cottage or suburban area.
The reinforced type of film is a modified version of polyethylene. Oilcloth has a special frame with a mesh thickness of 8-12 mm. The frame takes all the loads on itself, distributing them over the entire surface.
It is recommended to choose a film by density. This is due to the fact that the thickness of the material can be different: it will be thicker on the reinforcement than in the central part. For growing seedlings, a product with a density of 120-200 g per square meter is suitable.
The reinforcing frame can be made from various raw materials:
- polyethylene with special treatment. There are twisted, stretched, low pressure and monofilament options
On sale there is a special grade of breathable reinforced film, in which there are microscopic holes in the central part of the cells.
Fiberglass frame is a rare type of product, which is practically not used on the territory of Russia. Manufacturers claim that reinforced structures must last at least three years. The degree of wear depends on the climate of the region in which the products are used. The harsher the conditions, the faster the products will wear out. Therefore, the climatic conditions in which the film will be used should be taken into account before purchasing.
PVC films have sufficient thickness and do not rustle, as many believe. Outwardly, it is similar to the material used to make a medical dropper. This similarity is not accidental, since the same material is used in both cases.
PVC oilcloth has optimal properties for use:
- the translucency reaches 90%. This indicator indicates that the product transmits light at the maximum level, which saves on the arrangement of auxiliary light.
- PVC almost does not transmit infrared rays into the greenhouse. Only 10% of the radiation gets inside
- the transmission of UV rays is 80%.
Many users are discouraged by the high cost of products and poor frost resistance. The material is able to withstand temperatures up to -15 degrees. Despite the presence of significant disadvantages, the service life of the film is about three years with proper use. In regions with mild climates, the service life is extended to seven years
The product is produced in rolls weighing several kilograms. The material is in great demand as it has a more favorable cost compared to other greenhouse films.
The products are of high quality. Even if the material is left in the open air for several years, it will not lose its strength indicators. Traditional polyethylene canvases will begin to tear from light loads after a year and will crumble in the future. Stretch film is considered warmer, since it can be wound in several layers on the bars. No fastening is required for this material. It simply wraps around a frame or racks.
Manufacturers are constantly working on improving greenhouse films and releasing modified versions. Long-term products are in demand, which are divided into several categories, depending on the type of additives.
Perennial films are made mainly of polyethylene, sometimes you can find products that contain other polymers.
There is no specific list of characteristics, as they depend on the list of ingredients.
- Light stabilized. This film is highly resistant to sunlight.
- Hydrophilic. The products have a special layer that prevents the formation of condensation on the surface
- Heat-retaining. The film transmits a minimum amount of infrared rays into the greenhouse
- Anti-static film is capable of repelling dust
- Reflective sheeting can increase the amount of light required to grow seedlings. Available in black for weed control
- Light scattering. There are several types of such films, which differ in additives. You can choose material with phosphors, with UV absorption, with infrared reflection function.
Perennial films can combine several properties at once. On sale there is an option of five layers, which combines all the unique properties: the first layer is assigned high strength indicators, the second layer is responsible for blocking ultraviolet radiation, the third layer is responsible for light scattering, 4 is the regulation of thermal and infrared radiation. The fifth layer eliminates condensation on the film surface.
Bubble wrap is considered a perennial material.
It consists of three layers:
- the first two layers are made of polyethylene
- the inner layer is vesicular. He is responsible for reinforcement.
Many users are familiar with such a film, calling it "anti-stress". Most people are attracted by the opportunity to click the product for their own comfort. Thanks to the stabilizing additives, the service life of the products is about 3 years. The term is determined for the film that is not removed from the frame of the greenhouses.
Thanks to the air inside the bubbles, the material retains heat and can be used for winter greenhouses.
Reinforcing film: additional information for discerning buyers
Sometimes it is not easy to understand the quality of a product. You get convincing information from the seller, you buy a product, and it breaks, breaks, breaks down much earlier than the warranty period expires.
When buying a reinforced film, it is important to pay attention to its color; for use in greenhouses, the material must be white
When buying a reinforced film for greenhouses, the pitfall may be the use for the manufacture of not primary, but secondary raw materials. How can you find out? You need to figure out this issue yourself: no sales manager will share such information, even if he owns it. Do not be tempted to buy a cheap product unless it is marked on it as an economy offer. Read the information about the film carefully.
Be sure to familiarize yourself with the manufacturer's data (address and phone numbers), product dimensions, technical specifications, including a description of the composition, density and other characteristics, taking into account additives. If, according to the information, it was not possible to get a complete picture of the product, it is most likely not certified, therefore, you can forget about quality guarantees.
For those who plan to buy a tarpaulin awning, it will be useful to have the following information. When cutting fabrics for the manufacture of an awning, two technologies are used, more precisely, two measurements of sizes. The first option is when the final size is the official one, that is, if the parameters of the finished product are indicated. These awnings are sold under the Tarpix brand.
Density is one of the most important parameters to pay attention to when choosing a reinforced film.
The second type of designation of official dimensions is according to the cutting of the canvas, i.e. the size of the blanks is indicated on the tent. Naturally, the canvas is bent, some goes to the seams. These are Tarpaulin tents. If you bought a material with dimensions of 3x4 m, but it turned out that the sides are 20 cm smaller, this is not a deception - this is such a designation method. It is recommended to take into account the difference in size before purchasing the product.
You can list the positive characteristics and disadvantages of waterproof and vapor barrier reinforced film. You can talk about quality and disagree with the methods of designating sizes, prefer imported or domestic goods. But two indisputable advantages of the reinforced film cannot be denied: a reliable shelter is obtained from it, and the process of laying the material itself becomes much easier.
Features and dimensions of reinforced film
Reinforced film is a polymer material used in industrial and private construction, household and agriculture. It is one of the most reliable and durable polymers produced on the basis of polyethylene.
Hydrophilic covering material
This type of film provides additional protection against the formation of condensation, which can be detrimental to plantings.
Due to high humidity, molds or harmful microorganisms can appear.
The film contains special substances that can form condensation in the form of a flooring, which will not harm the plants in any way. This film is much thicker than polyethylene, its thickness reaches 150 microns. The warranty period is 3 years.
Film coating properties
Polyethylene film is used not only in agriculture, but also in construction, as well as for packaging various goods. However, not every roll film is suitable for covering greenhouses. Types of films made of low-pressure polyethylene have low strength, poorly tolerate temperature extremes and solar radiation.Such a film is deformed and torn after 2-3 months in the summer, and cracks when the temperature drops below -10 ° C in winter.
Professional greenhouses under the film
There are several types of film for greenhouses:
- high pressure polyethylene
- light stabilized polyethylene
- light-transforming, heat-retaining film
- ethylene vinyl acetate copolymer film "Svetlitsa"
- PVC film
- reinforced polyethylene
- air-bubble, from 4 to 10 mm thick.
Films for covering greenhouses, regardless of the type, have common advantages and disadvantages.
Features of film coatings for greenhouses:
- easy installation, repair or replacement of the film
- low weight and low load on the frame
- a wide range of thicknesses, widths and types of films.
To improve the characteristics of the film, various components are added to the polymer to give it special properties.
- Light stabilizers - components embedded in the polymer chains of the material and reducing the harmful effects of solar radiation on the structure. The film with light stabilizers does not deteriorate after several months of use, even under the bright spring and summer sun. In addition, the light-stabilized film has greater elasticity and frost resistance; it does not have to be removed for the winter.
Light stabilizers or UV stabilizers
The addition of only 1% of 104355-E antistatic agent is sufficient to prevent dust accumulation on the surface of EVA films.
Effect of using chalk additive F-2 in LDPE films of various thicknesses
Slip additives improve plasticity and smoothness of the film surface, make it more pleasant to use.
Influence of the combined additive (sliding + antistatic agent) on the technical parameters of the blown film made of high pressure polyethylene
Phosphors - components that help convert ultraviolet light waves that are useless for plants into the visible part of the spectrum. This increases the illumination of plants, accelerates photosynthesis and growth. Another feature of light-transforming films is the weak transmission of infrared rays outside, due to which the greenhouse gives off heat more slowly at night.
Comparative Results of Phosphor Life in Film
Note! Determining a film with phosphors is quite simple: you need to shine through it with an ultraviolet lamp or blue LEDs. The light passing through the film should turn red.