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Arrangement ventilation greenhouses are one of the main challenges faced by vegetable growers with the onset of the hot season.
Indeed, for the normal growth of plants, certain conditions are required. temperature and humidity.
And this cannot be achieved without quality airing.
Why do you need to maintain temperature and humidity?
Each type of plant has its own indicators. optimal temperature... In this case, not only the air temperature in the greenhouse is important, but also the soil temperature. It is these factors that explain the effectiveness of the harvest in the fields of one vegetable, and at the same time the failure of another.
Therefore, each type of seedlings grown in the greenhouse must be provided with favorable conditions for healthy life and growth.
Air temperature and soil in the greenhouse affects the rate of absorption of nutrients by plants. An indicator of how well the temperature regime in the greenhouse is organized is the good development of the root system.
At a temperature below 10 ° C plants begin to absorb nutrients more slowly. Therefore, the soil temperature, depending on the crops grown, should be from 13 to 25 ° C.
Reference: for the qualitative development of the root system in the daytime and at night, the temperature in the greenhouse must be maintained. For this, temperature controllers are often installed indoors.
Increasing the temperature in the greenhouse affects the growth rate of the plants. But here it is important to know when to stop, since too high a temperature (for example, more than 40 ° C) can lead to death seedlings.
Insufficiently heated soil will cause phosphorus starvation of plants, but even at elevated temperatures, the roots may not be able to absorb moisture well, which can cause wilting and drought, even on well-moistened soil.
Greenhouse plants also need to maintain a certain humidity around the clock.
During the day and at night, at various stages of development, seedlings need different humidity modes.
Thus, low moisture levels especially affect plants during seed germination and flowering and can cause poor growth in crops.
In addition, dry pollen during the period of pollination loses its ability to pollinate, and in hot climates it generally becomes sterile, which leads to lack of ovaries on the brushes of plants.
In addition, the presence of dry air in the greenhouse favors the appearance of mites when growing cucumbers.
Greenhouse ventilation: what is the reason for this?
There is only one way to achieve a normal temperature regime - it is to replace hot air in a greenhouse on cool air currentscoming from outside the premises. In addition to cooling, ventilation also solves other tasks aimed at maintaining favorable climate conditions inside the greenhouse structure, namely:
- shaping temperature and humidity air and soil;
- uniform circulation air masses;
- balance air composition (ensuring the required content of oxygen and carbon dioxide).
Reference: in certain cases, ventilation is used to hardening of seedlings, thanks to which the plants adapt more easily when planting in open ground.
By management method ventilation systems for greenhouses are:
- mechanical (doors and fanlight sashes are opened and closed manually);
In the greenhouse automatic ventilation (use of a thermal drive) is divided into several types:
- electrical ventilation system for greenhouses... Affordable. Consists of a thermostat and an electric fan. The mechanism is triggered when the set temperature is exceeded;
- hydraulic... A device based on a hydraulic cylinder, with the help of which the transoms are opened and closed. The mechanism comes into action due to the expansion of the liquid inside the device with an increase in the air temperature;
- bimetallic... Works by varying the expansion coefficients of the two metals. When heated, one plate bends, opening the transom;
- automatic window.
Microclimate control system
Control system microclimate greenhouses are used to maintain optimal levels of four parameters: humidity and temperature in the greenhouse, lighting and carbon dioxide content. For this, the greenhouse is equipped with:
- heating and ventilation system;
- CO2 feeding system.
System operation is monitored using special control controller, and measuring sensorslocated inside the greenhouse. In addition, the system is equipped with weather station, which includes a whole set of different sensors in its design.
Microclimate control system has the following functionality:
- greenhouse climate control;
- installation of temperature and humidity conditions;
- tracking outdoor meteorological conditions;
- preservation and analysis of the obtained indicators.
In industrial buildings
In most cases, industrial greenhouse structures are equipped with combined ventilation system.
In this case, the ventilation technology in industrial greenhouses is carried out by combining natural air exchange with artificial mixing of air in the room using fans suspended from the ceiling.
Air enters the greenhouse through transoms, which are used to open hydro- or electric drive.
The openings open automatically, while the flaps are opened not one by one, but in a complex manner, maintaining the required angle.
The combined ventilation method can also be used in large home greenhouses.
For ventilation in a polycarbonate greenhouse, you need to equip a structure vents, which can be of a conventional design or a blinds forum. In the presence of vents in the form of louvers, the air enters the room evenly, which helps to prevent the formation of drafts.
In addition, a polycarbonate building can be equipped with various types automatic ventilation system.
Electric ventilation system
With this method, air exchange occurs due to supply ventilation system, which turns on at a certain time in accordance with the specified settings or when the required temperature in the room changes. Air is removed by means of exhaust fans.
Suitable for air circulation household fan, which is installed on the wall indoors.
It is also possible to organize air exchange by automatic opening of vents, however, such a system requires special drives, the installation of which is not only difficult, but also associated with considerable financial costs.
This method implies using hydraulic cylinder, which includes in its design the stem, pipe and O-rings.
The oil contained inside the device expands when heated, setting in motion the stem, under the influence of which the transom opens.
The device is installed on the ridge of the roof of the structure and is fastened with brackets.
The rod is connected to the upper flaps by means of flexible rods.
The importance of having good ventilation in the greenhouse obvious.
This process plays a key role in ensuring healthy growth and plant development, regardless of the type of crops grown. Good harvests to you!