Advantages and disadvantages of plastic wrap greenhouses, popular frame designs. The choice of material for the coating and methods of fastening it, the technology of building assembly. Greenhouses with polyethylene cover are the simplest structures for growing seedlings and early vegetables. They do not require heating, they are quickly assembled and disassembled, which makes them the most popular among similar buildings. How to choose the right frame, assemble it and cover it with foil, we learn from this article.
Features of the design of greenhouses made of polyethylene film
A typical polyethylene lined greenhouse is a lightweight structure with a translucent top. There are many quick-build buildings, each of which has certain advantages. Before you make a greenhouse from a film, you need to choose the right design that is suitable for a particular suburban area.
The most popular bases for polyethylene are arched (metal or plastic) and wooden frame-type structures. As a rule, their dimensions do not exceed the indicated values: length - 6-7 m, width - 2.4 m, height - 2.5 m.
An arched greenhouse has an arc-shaped roof. It has the following advantages:
- Ease of installation;
- Low cost of building materials for the construction of the frame;
- Resistance to mechanical stress;
- Good illumination due to the large area of polyethylene cover;
- In winter, snow does not accumulate, so the film can be left on during this period.
Frame-type greenhouses are single-slope and gable. The first ones are not mounted separately, but are attached to the southern side of a building. A noticeable disadvantage of this design is the manual removal of snow from the roof, which is not very good for a polyethylene coating. Gable greenhouses are easy to use, because there is a lot of space inside.
From the point of view of operation, the structures are divided into winter and summer ones. Winter ones are made of reinforced film and have a complex device that includes various systems - heating, fire fighting and others. They are often buried 1–2 m deep in the ground.
Summer buildings are usually quickly dismantled in order to be dismantled for the winter. The frame is made of plastic, metal or wood.
Advantages and disadvantages of plastic film greenhouses
Greenhouses have been covered with polyethylene since the last century. Users note the following positive aspects of the material:
- It is the cheapest of all products for a similar purpose. Its use allows you to save financial investments in the construction.
- Greenhouse film does not allow moisture to pass through and reliably protects crops from rainfall.
- It is elastic and can withstand high tensile loads. The stretch ability makes the installation process easier.
- The product can be conveniently attached to a frame made of any material.
- The film is permeable to oxygen and carbon dioxide and does not absorb ultraviolet light and most of the solar spectrum. The cover diffuses direct sunlight, which increases the yield.
- The dimensions of modern polyethylene products remain unchanged throughout the entire service life. They do not change under the influence of wind and atmospheric precipitation.
- Fungus does not take root on the film, it is non-toxic, odorless.
- The material is safe for plants.
- Good resistance to acids and alkalis.
However, polyethylene has drawbacks that the owner of the dacha must remember. These include the following:
- It has a weak weather resistance, so it quickly breaks down. Over time, even a dense product becomes fragile.
- Reduced transparency due to the property of the material to electrify and attract dust. Greenhouse coverings need to be washed frequently to increase their light transmission performance. Also, the film becomes cloudy under the influence of oxygen, moisture and ultraviolet radiation.
- Loss of shape due to elasticity, which leads to sagging of the panel.
The latest models are devoid of such disadvantages, which allows you not to change the greenhouse cover for several years.
Film greenhouse construction technology
The methods of erection of structures of various structures are in many respects similar. Construction is carried out in several stages. Each of them is described below.
The choice of plastic film
The design is covered with a panel, which is selected depending on many factors. Without fail, the coating is removed at the beginning of winter. Even a film of great strength does not withstand the tests of frost, wind and snow.
When buying, consider our recommendations:
- The main characteristic of polyethylene is its density. The ability to withstand the load from wind and precipitation and transmit light depends on it. The larger it is, the worse the lighting inside. Low density products break easily and may fail before the end of the season. The best option that meets these requirements is considered to be a material with characteristics of 150-200 microns.
- The width of the panel depends on the size of the structure. Small tunnel greenhouses (for example cucumbers) can be covered with samples 3 m wide.
- For large stationary buildings, it is recommended to buy 6-meter products. They are usually sold folded in half, in the form of sleeves, 3 m wide. Before pulling, the cuts are cut.
- If the width is not enough, the individual parts are glued or welded.
We suggest that you familiarize yourself with the characteristics of the most popular types of plastic films:
- Unstable film … It allows up to 80% of thermal and ultraviolet energy to pass through, so it is cold under it at night. Differs in low wear resistance, despite the addition of light stabilizers, which increase the mechanical strength. Service life - 5-6 months. One of the few advantages is the low price.
- Stabilized hydrophilic film … It contains stabilizing additives that increase resistance to light. They are often produced in various colors - blue, orange, pink. They are distinguished by a special surface structure that allows condensation to form. Moisture rolls down without droplets. The material is impregnated with antistatic agents, which prevent the build-up of static electricity and attract dust. The surface always remains transparent. The canvas does not transmit infrared rays, so little heat escapes through it at night. Reducing daily temperature fluctuations increases the productivity of the garden.
- Light scattering film … It can reflect light or absorb ultraviolet light, depending on the additives. The product distributes light evenly over the entire area. If the area is in the shade, you need to choose a material that lets in more light. Under such a coating, unpleasant moments do not arise when leaves are burned on the plant due to a drop of water. Reduces the risk of damage to cucumbers, which are recommended to be watered in the middle of the day.
- Heat retaining film … Has an increased level of thermal energy absorption. Under it, the temperature is 1-3 degrees higher than in other structures. Its use can increase the yield by 10-30%. It is easily recognizable by its matte white shade. But the coating has a small margin of safety and can withstand only 9 months of operation.
- Reinforced film … Durable material reinforced with dense threads forming 6x12 mm cells. The coating can last more than 2 years. You can leave it on for the winter. But it passes thermal energy 10-12% lower than other samples.
Preparatory work
To quickly assemble a greenhouse and start operating it, prepare in advance for the process.
Perform the following operations:
- Choose a place to build. Greenhouses are built on a flat, well-lit place with an average level of humidity, with soil of the same composition.
- It is recommended to prepare the soil in the fall so as not to waste time cultivating it on nice spring days. The site must be dug up, fertilized, leveled with a rake.
- Perform such work that cannot be done after the installation of the structure, for example, if the greenhouse is year-round, mount a heating system under the beds.
- At the places where the load-bearing elements are installed, compact the soil.
- Treat wooden elements with antiseptic agents. Without protective impregnation, lumber will rot in a few years.
Installation of the frame for plastic wrap
Consider assembling the base of the most popular greenhouse shape - arched. The load-bearing elements of the frame are made of metal or plastic pipes. The first option is more durable, and such a structure can not be disassembled for the winter. The advantages of the plastic frame include simple installation, without the use of welding or adapters to connect the elements together. It is recommended to develop a drawing of a greenhouse for a film, which should show all the elements of the structure and how to fix them.
For work, you will need the following materials:
- Pipes - metal or plastic with a diameter of 25-30 mm. A film is attached to them.
- Resinated timber or logs with a section of 100x100 mm, treated with antiseptic agents, which are used as a base. The massive lower part of the structure will add rigidity to the structure.
- Metal pins or fittings about 1 m long and 15-20 mm in diameter, with which the base is attached to the ground.
- Metal rods 80-100 cm long, on which plastic pipes are put on. The pins should be of such diameters that plastic pipes can be put on them.
- You will also need additional pipes, which are laid at the top of the arcs and on the sides of the structure, in two rows, to give it rigidity.
Consider the assembly of an arched frame made of plastic pipes, which can be completed within a few hours.
The work is performed in the following sequence:
- Assemble a box of beams that will support the entire structure and provide it with rigidity. Put it in a place prepared in advance.
- At the corners of the box, drive metal pins into the ground to fix the product.
- Drive metal rods into the ground to a depth of 50 cm along the long sides of the base, onto which the arches will be put on. The same amount should come out. The distance between them is 50-60 cm.
- On each pair of pins located on opposite sides of the box, put plastic pipes in such a way that an arc is formed. The length of the element can be determined empirically. To do this, you will need assistants: one puts the pipe on the pin, the second holds it in the middle of the greenhouse, and the third marks the place of the cut for the second pin. The rest of the pipes can be cut according to the first sample, using it as a template.
- Fix the elements in their places with mounting loops, which are fastened with screws to the box.
- Reinforce the structure with props made of a bar with a section of 5x5 cm, placing them at the ends of the structure.
- On top of the arches, place a plastic pipe that will provide stability to the greenhouse.
- Fix on the sides of the pipe with two rows of purlins. Secure them with bolts or welding. It is possible to fix metal elements with a bolted connection, but for this it is necessary to weld brackets to the arches. Do not drill holes in the arcs, you will weaken the structure.
- Knock down the door frame and secure it to one of the ends of the greenhouse.
- Make the frame of the door according to the dimensions of the box. Cover it with foil and fix it in its original place.
- Make ventilation vents in the same way. They settle at the ends of the structure, above the door, as high as possible.
- If the building is large, shelves with earth can be built inside.
- After the construction of the frame, fix the film.
Fastening the film to the frame
Polyethylene is not the most durable canvas, the weakest part of it is the attachment point. This is where it breaks due to friction or from stretching when heated. Therefore, there are special fixation rules that depend on the base material - wood, metal, plastic. Let us consider in detail the methods of installing greenhouse polyethylene film.
When covering a greenhouse with a wooden frame with foil, the following rules must be adhered to:
- The beams at the polyethylene attachment points should be sanded and painted with light paint that reflects sunlight.
- The easiest way is to use glazing beads or strips that press the canvas. They are fixed with nails. This option has disadvantages - over time, the wood dries up, and the material is held only by nails. In this case, the polyethylene tears quickly.
- To extend the life of the coating, treat the slats with an antiseptic and paint, and use screws instead of nails. Screw in the fasteners every 20-25 cm.
- A more reliable way of fastening is to use pads. They are made of wooden planks 10 cm long and equal to the thickness of the frame. Round the edges of the block and sand it. Cover the surface of the workpiece with rubber glue and wrap it in several layers with plastic wrap. Make the required number of overlays, based on their laying in 20 cm increments.
- Stretch the canvas and coat it with rubber glue in the place where the overlays are placed. Place the workpiece in the intended place and secure with wood screws.
- You can use plastic packaging tape to secure the cover, which does not deteriorate or deform. It is attached to the lumber with a stapler.
- A more economical way is to cut strips of old linoleum, glue to the film and secure with a construction stapler.
- To fix around windows and doors, cut the canvas with a margin, wrap it around the rack several times, and then nail it.
The metal base heats up more than wood, so the polyethylene stretches and tears faster. Before fixing the film on such a greenhouse, carefully insulate the metal surface. If the frame is made of pipes or fittings, you can put a hose cut along them on them. Wrap the profile pipe with a thick white cloth. The method of fastening the film does not differ from those used for wooden products, but it is first necessary to make holes in the metal for fasteners.
It is allowed to use a coarse mesh or cord for fastening the panel. Before using the rope, first pull the cloth and secure it temporarily. Secure the cord at the bottom corner of the greenhouse. Throw over the top and pull. Then pass the cord under the longitudinal rail and zigzag it back. The cord is also pulled from the inside so that the cover rests on it.
The film does not need to be unrolled or cut. Pass the cord into the sleeve and secure it at the bottom of the greenhouse. Throw the workpiece over the structure and repeat the operation. Pull the next section with an overlap of 15 cm on the first. This method increases the consumption of material, but extends its service life.
It is best to fasten the canvas to the reinforcement with special clothespins.
Plastic barely heats up in the sun, so it does not require insulation. In stores, you can find special clips for fixing the film to the frame, but you can make them yourself. To do this, cut pieces of pipes 8-10 cm long and cut them lengthwise. Sand the edges of the cuts and remove any sharp edges and corners. For fastening, pull the plastic and press it against the pipes with the made clamps.
Film welding rules
With large greenhouses, the question often arises of how to connect the individual parts of the plastic wrap. The problem can be solved by welding the parts using one of the proposed methods.
Welding with a soldering iron is performed in the following sequence:
- Wrap a 25-40 mm flat strip with a thick cloth.
- Place it on a flat table with its wide side.
- Place the edges of the polyethylene pieces on the rail with an overlap and secure with a load.
- Cover the joints with newspaper to prevent the plastic wrap from sticking to the instrument.
- Heat your soldering iron or iron to 120-140 degrees.
- Practice on an unnecessary piece of polyethylene to determine the speed of the tool. You cannot keep it in one place for a long time, but it is also not recommended to move it quickly.
- Iron the joints with an iron or soldering iron.
To connect the cuts with a blowtorch, press down the edges of the product with metal clips. Heat the protruding parts with a blowtorch until a seam appears. It can be trimmed with a rubber spatula or plank.
How to make a greenhouse from a film - watch the video: [media = https://www.youtube.com/watch? V = _3h0z92SDqw] There are a large number of greenhouse structures covered with plastic wrap. They do not require much time to manufacture, but to obtain a good result, the assembly procedure must be performed carefully due to the low strength of the web. In order to properly build a greenhouse from a film with your own hands, you should study the sequence of work in advance and not deviate from it.
