In our latitudes, agriculture is limited to four months a year. With own garden during this time it is usually possible to harvest without nitrates and other substances harmful to humans. In order to extend the period of growing crops and be able to get organic vegetables, even in winter, it is necessary to build on the site greenhouse. Here we will talk about how to build a greenhouse with their own hands, what materials are used to them, as they have, ways of heating and lighting.
From a school course of botany, everyone knows that the development of plants provides a process of photosynthesis, which requires light, air, heat and moisture. Therefore, to create conditions in the greenhouse should take into account several factors - its appearance, size, and translucent material, the organization of additional lighting, ventilation, air heating and irrigation.
The construction of greenhouses
Before considering how to build a greenhouse, you should understand what they are. Greenhouses by design divided into arch and tent. Hip design in appearance resembles a small house, as formed by vertical walls and pent, gable, flat or arched roof. Sometimes the opposite wall slightly tilted inward. Arched same design in appearance resembles a tunnel made of transparent material. Its structure consists of parallel arcs connected together, and ends with flat walls. The frame is assembled from angle steel or aluminum by means of screw connections or welding. Steel structures primed and painted or zinc for corrosion protection and aluminum profiles there is no need to protect.
The most comfortable height la greenhouses 2-2, 5 meters, and the width of 2, 5-3, 5 meters. Although the use of absolutely any size. This width allows you to make three beds with two tracks between them instead of two on one side of the central walkway. Though useful area while slightly reduced, but to work in a greenhouse is much more convenient. The width of the ridges, mainly depends on the crop. It is recognized that the optimal distance from the plant to the edge of the beds, especially if it is located near the walls must be 30-40 centimeters.
The length of the construction can be varied as a greenhouse assembled from individual sections. The end walls are provided folding, hinged or sliding doors, which are needed not only to maintain but also to ventilate the greenhouse. Also, arrange for ventilation flaps or pivot ridge transom. In standard tent greenhouses they are usually up to three pieces on each side of the ridge, but you can install any number.
Translucent coating greenhouses should not only possess the optical properties of a certain limit, but also be sufficiently strong and withstand temperature extremes from -20 milking +60 ° C. Task translucent coating - skip radiation in the range of PAR providing photosynthesis. In addition, it must pass no less than seventy percent of the infrared and the near and far ultraviolet radiation, which transmit solar energy plants.
As the use of translucent glass coating or film - polyethylene or polyvinyl chloride. In recent years, for the construction of greenhouses using plastics. For those interested in how to build a greenhouse made of polycarbonate with his own hands, will have a value that today is widely spread relatively new material - polycarbonate. All of these materials are characterized by their translucency, which indicates the ratio of transmitted light to the total energy of the radiation.
All of these materials are missing most of the PAR radiation and near ultraviolet range. Infrared and far-ultraviolet range, they passed enough and should compensate for artificially. The missing heat wave infrared radiation in a greenhouse heated make up air heating appliances and compensation for the far ultraviolet radiation provides dosvechivaem special ultraviolet lamps.
For the tightness of the greenhouse glazing glued rubber profile that ensures a stable microclimate necessary. These rubber seals provide ozone, moisture, and light resistance. Today, manufacturers produce a variety of prefabricated greenhouses. Some of them are used for glass rails, equipped with locks. They make it possible to remove a sheet of glass in a couple of minutes. But it is much safer and more convenient to use as a translucent polycarbonate cover. It is not only stronger and lighter than glass, but also less fragile.
Especially suitable for the construction of cellular polycarbonate arch greenhouses. In addition, it looks more attractive thanks to him, such a greenhouse at the same base area has a larger volume than the hip. This means that it has more volume and air. Previously, only the arched greenhouse glass end walls and the spaces between the arched arches covered with a film, which was shot in the winter. Above the door or next to her in the end face is provided vents. Polycarbonate, which is easy to bend, will close the entire framework, and to dismantle the winter need not be. In addition, if the need arises in the capital intensive airing or drying greenhouses, on the one hand, you can release the plastic sheets, without any damage to the entire structure of the greenhouse.
Positioning the greenhouse at the site should be, depending on how you intend to use it. If it is used all year round, it is best to focus from west to east. If it is assumed that the ground will have a rest in the winter, the greenhouse is best placed from south to north - this will reduce the risk of burns summer plants. Conveniently positioned with a hip greenhouse shed roof so that it bordered on the south side to the blank wall of the house. This will significantly reduce the amount of required energy in its heating. The best for our region roof angle to the horizon line - 25-30 °. To avoid the appearance of a wall between the house and a greenhouse mold and damp, you need to make between the waterproofing of glassine paper or roofing material.
With year-round use at the tent greenhouse is best done long walls tilted inward at 10-15 °. This will allow in the winter is better to accumulate solar energy. It should take into account the cold wind and provide protection against them, because they may increase by half the energy loss. To do this it is best to plant in the lee of a hedge, the distance to which must exceed 5-10 times the height of the greenhouse. With frequent northerly winds allowed to establish a greenhouse next to some buildings, because the shadow of it will not be too much in that direction.
A place where you intend to install the greenhouse, it should be smooth. If the site is not a place, it will be necessary to equip the bulk area. Under a glass greenhouse is best done with a metal strip foundation reinforcement to the location of the foot to a depth of thirty centimeters. Such a strong and rigid construction gives an opportunity to eliminate distortions and cracks foundation, which respectively may cause misalignment of the framework and then to cracking of the glass. If the water table is at a depth of less than 0, 6m, you must also provide a drainage system. Because the excess moisture can lead to heave that impair the development of plants.
Water, heating and ventilation of greenhouses
With the help of convection can be aligned in the greenhouse air temperature and mix. But it does not provide a supply of fresh air is a must have plants in the dark to the process of breathing. Everyone knows that plants mainly produce oxygen during the day and night to absorb. The microclimate of greenhouse differs from the natural fact that the temperature and ventilation is not only selected, but are supported so as to provide optimal conditions for growing plants.
Relative humidity in the greenhouse should be about 70% and the temperature is selected by taking into account specific plants, so that they do not overheat and drying out. In the absence of the greenhouse heating temperature depends on heat transfer conditions. That is why great importance is the amount of greenhouse. It affects the rate of temperature change after sunrise or sunset. To simplify the maintenance of the system, the rate should be linked to climatic conditions.
To plants developed normally, so they will not rot or "burning", especially in summer, humidity and temperature in the greenhouse is controlled by airing and venting. Air ratio in practice in a cloudless sky in the summer should be a multiple of fifty. For ventilation even small greenhouses need some pretty powerful devices. To reduce costs, the ventilation can be combined with ventilation. Due to the well thought-out organization of ventilation is possible and completely eliminate ventilation.
Air exchange when using the ventilation can be controlled by time or thermostat. Airing is difficult to manage - will sit for days near the greenhouse, closing vents and skylights. Left unattended as a greenhouse is difficult to protect from the weather - rain, wind, hail. Ventilation should provide the necessary ventilation. Most often with the help of the inflow of the lower part of the greenhouse air, which rises progrevshis and out through the skylights in the roof. Keep in mind that this process is necessary to cover the entire amount of the greenhouse, leaving nowhere stagnant air.
In practice, the organization of air used by the two equivalent circuits:
- Fresh air and through the roof of his hood on opposite sides of the greenhouse;
- inflow from the bottom - in the middle or on the edges and through the roof hood, also at the edges or in the middle.
Fresh air ventilation is carried out, opening for this ridge skylights and doors. In the tent of the greenhouses to provide additional vents in the walls. If you wish, you can automate the greenhouse ventilation by installing a special mechanism with hydraulic fluid that does not freeze. If the temperature in the greenhouse rises, the fluid being heated, it expands and pushes the plunger, which lifts the window. And vice versa.
Ventilation air dry in a greenhouse. Therefore, it is necessary to provide hydration to maintain the necessary humidity. But it should be taken into account and that too in a moist environment and rapidly developing plant disease, and if the air is too dry, they die. The issue is solved humidity creating a mini-irrigation system, which is automatic or semi-automatic mode can provide the necessary irrigation. Such systems are controlled by special sensors.
In the presence of running water in a greenhouse greatly reduced volume of work. Create better water using plastic pipes, which are provided with thermal insulation. For convenience and safety of them is conveyed in the ground with access already in the greenhouse.
Growing plants in a greenhouse at outdoor temperatures below 5 ° C is possible only with the mandatory air heating because the heat accumulated by the day due to solar energy is not enough to maintain the microclimate in the greenhouse at night for security and preservation of plant life. We must also take into account that the sun is not every day. To ensure the appropriate temperature, there are different types of heat sources, but choosing them, it should be remembered that the energy dissipation greenhouse is much higher than residential house. Therefore, year-round greenhouses have provided a better seal than seasonal.
Electrification of the greenhouse it easier for you to service. In addition, it will provide an opportunity to use additional equipment such as UV lamps for supplementary lighting plants. As additional sources of heat pipe can be used, which have around the perimeter of the greenhouse walls. Sprinkler-irrigation system can be made mobile. Between the spray nozzles is the optimal step 1, 6m.
Given all the above rules the construction of greenhouses and equipment, you can not give up all year round on the site to summer.