Why is the temperature in the greenhouse high, and how much can the greenhouse temperature reach in

The temperature in the shed is variable, and although it varies regularly, it is very difficult and unrealistic to determine the temperature at all points. However, if it is specific to a certain point, the temperature of the shed is very easy to determine, and from the temperature of this one point, we can deduce the approximate temperature of other points.

Generally speaking, 30 is the upper limit of the most suitable temperature for most nightshade vegetables and melon vegetables, and on this basis, increase by 2-3 to make the shed temperature reach 32-33, which is the theme of the shed temperature control that I want to talk to you.

So, why is the temperature so regulated? From the perspective of the actual production operation of vegetable farmers, the temperature can be controlled to the most suitable range for vegetable growth.

First of all, the thermometer in the shed is mostly hung on the upper part of the plant, and the air temperature of different parts of the day is basically positively correlated with the height of the plant, especially when the plant is lush and high, due to the shading effect of branches and leaves, the temperature drop gradient is very obvious when measured from the growth point to the ground. Generally, the ground temperature can be 3-7 lower than the temperature at the growing point, if the temperature at the growing point of the crop is about 34, then the temperature at the main branch and leaf of the crop is just between 27-30, which is in the most suitable temperature range for photosynthesis.

Secondly, shed cultivation, covered with plastic film, soil moisture is sufficient, thereby accelerating the transpiration of crop leaves, reducing the leaf temperature, the leaf temperature, generally lower than the air temperature 3-5, even if the air temperature is significantly higher than the light temperature 2-4, the leaf temperature is still within the suitable temperature range for photosynthesis.

Again, raising the air temperature in the shed is conducive to the increase of ground temperature. If the ground temperature is low, it is not only not conducive to the growth and development of crop roots, resulting in less rooting, poor root absorption capacity, and low physiological activity, but also will cause the occurrence of a variety of physiological diseases, and even rotten roots, dead roots, and crop death.

In general, the temperature of the soil at a depth of 5 cm during the day can be 5-7 times lower than the temperature in the shed, and the ground temperature at a depth of 5 cm at night is 3-5 times higher than the air temperature. It can be seen that the temperature in the shed is lower than 20 for most of the day, which is 3-5 lower than the soil temperature of 23-25 suitable for the root growth and development of melons and fruit and vegetable crops.

The higher ground temperature can promote root development, increase the amount of rooting, improve root activity, and promote the absorption, transformation and utilization of water and nutrients by roots. So as to achieve the purpose of promoting the growth and development of crop shoots, improving crop yield and quality.

Therefore, I said that the temperature of the shed should be adjusted to the upper limit suitable for crop growth and add 2-3 to the upper limit.

The top of the greenhouse is made of glass, and the sunlight can enter the greenhouse through the glass, but the infrared rays in the sunlight can't get out, and the temperature is high, so there is a reason for you to ask.

This is determined by the windshield wall of the greenhouse.

wall thickness and artificial heating measures. I know that there are places where the greenhouse can maintain 30 degrees in winter, and it is said that in order to maintain the high temperature in the shed in the summer in the harsh winter season, in addition to the thickness of the wall, polyvinyl chloride film is also used to increase the light transmittance, the new construction technology is used to enhance the closure of the shed, and the 15 kg straw curtain is used to increase the thermal insulation performance.

1 The temperature in the greenhouse is about 7 or 8 degrees in the morning, and the temperature increases as the sun rises. Generally, it can reach 30 degrees, but generally vegetables can't stand this or above temperature, so it is necessary to release the wind, which is generally controlled at about 20-25 °, especially in the middle of the night, it will be relatively low, below 0 °, and even lower when the weather is cold. If it is minus 6 degrees outside, it can generally be maintained at 7 or 8 degrees in the shed, if the insulation measures are done.

2 15-25 ° is very easy, just in the roof of the roof of the sixth tuyere, no additional measures are needed, the air outlet will be enlarged and ventilated in hot weather, and the air outlet will be closed in cold weather. How can there be a lack of oxygen if there are plants in the greenhouse? I am afraid of the lack of carbon dioxide, which is also the reason for the air outlet.

3 400 square meters need more than 10,000 in the first year, and several thousand in the second year, mainly to buy medicine and film, and the backbone can be used for many years. There is no need to add money to the constant temperature room.

1. The temperature in the shed in the morning is about 7 degrees, with the higher the sun, it can generally reach 30 degrees, the vegetables should be ventilated, controlled at 20-25 degrees, lower at night below 0 degrees, and the outdoor minus 6 degrees, the shed is maintained at 7-8 degrees.

25° is very easy, on the roof of the greenhouse No. 6 tuyere, no additional measures are required, the tuyere will be enlarged and ventilated in hot weather, and the tuyere will be closed in cold weather.

Generally sunny days, ventilation when the temperature in the shed reaches 28-30 during the day, and proper ventilation to maintain the temperature of about 20 on cloudy days.

It is generally in the 30s Celsius.

How much does the greenhouse on the picture cost.

The plastic film has thermal insulation, after covering the film, the turbidity in the greenhouse will increase with the increase of the outside temperature, and decrease with the decrease of the outside temperature, and there are obvious seasonal changes and large temperature difference between day and night, the lower the temperature difference in the lower temperature period, the greater the temperature difference, generally in the cold season in the greenhouse daily temperature increase can reach 3-6, cloudy days.

or the nighttime warming capacity is only 1-2.

In the warm spring season, the temperature difference between the shed and the open field gradually increases, and the temperature increase can reach 6-15. When the outside temperature rises, the temperature increase in the greenhouse is relatively increased, up to more than 20, so there are high temperature and freezing hazards in the greenhouse, which need to be manually adjusted. In the high temperature season, more than 50 high temperatures can be generated in the shed.

Carry out full shed ventilation, cover the outside of the shed with a straw curtain or build a pergola, which can be 1-2 times lower than the temperature in the open field. In winter, when it is sunny, the minimum temperature at night can be 1-3 times higher than that in the open field, and on cloudy days, it is the same as in the open field. Therefore, the main production season of greenhouses is spring, summer and autumn.

Through heat preservation and ventilation cooling, the greenhouse temperature can be maintained at 15-30 for growth.

The main device of the greenhouse.

an indoor greenhouse cultivation device, comprising a planting trough, a water supply system, a temperature control system, an auxiliary lighting system and a humidity control system; The planting trough is set at the bottom of the window or made into a partition for planting plants; The water supply system automatically supplies the right amount of water at the right time; The temperature control system includes an exhaust fan, a heat fan, a temperature sensor and a thermostatic control box to adjust the temperature in a timely manner.

The auxiliary lighting system consists of plant lamps and reflectors, which are installed around the planting trough to provide illumination when there is no sunlight, so that the plants can photosynthesize and present a beautiful landscape through the refraction of light. The humidity control system works with an exhaust fan to regulate humidity and reduce room temperature.

1. For solar radiation, plastic greenhouses and glass are almost transparent, and solar radiation can enter most of them. However, for the long-wave radiation on the ground, the plastic greenhouse and glass are opaque, so that the greenhouse and the greenhouse can make the solar energy from the outside continue to enter the room, and the indoor heat is rarely lost, so as to play a role in regulating the temperature.

2. Therefore, the sunlight shines into the greenhouse through the film, and the temperature is firmly locked by the film, so the temperature is relatively high. The surface itself also has temperature, due to the barrier of the film, the cold air outside can not enter, can not contact with the indoor air so that the temperature will not drop, the function of the film is only into the sunlight and not into the air, so the indoor temperature is much higher than the outdoor temperature.

Summary. Regardless of day or night, the indoor temperature of the greenhouse is lower than the outside temperature, which is a fallacy and untenable. People use greenhouses to plant in order to increase the ground temperature and promote the growth of crops in colder climates.

If the temperature is cooler at night than outside, wouldn't it freeze the crop to death?

The so-called greenhouse is to use the temperature absorption of plastic or sunlight panels to increase the temperature in the shed, and then use the airtightness of the greenhouse to keep warm to ensure that the temperature in the shed is higher than the outside temperature. Because the greenhouse heats up quickly when there is sunlight during the day, and the temperature drops faster when there is no sunlight at night, resulting in a large temperature difference between day and night in the greenhouse, sometimes it gives people the feeling that the temperature in the greenhouse is quite low at night, which is just relative to the warmth of the day, not relative to the outdoor temperature. In addition, there is often more moisture in the greenhouse, and when the temperature drops at night, the humidity in the shed is larger, giving people the feeling of being wet and cold, which is more thorough than the outdoor cold.

But if you measure it by temperature, the temperature inside the shed will definitely be greater than the temperature outside.

Why is the temperature lower at night in the greenhouse than outside?

Regardless of whether it is during the day or at night, the indoor temperature of the greenhouse is lower than the outside temperature, which is a fallacy and untenable. People use greenhouses to plant in order to increase the ground temperature and promote the growth of crops in colder climates. If the temperature is cooler at night than outside, wouldn't it freeze the crop to death?

The so-called greenhouse in Tanla is to use the temperature absorption of plastic or sunlight panels to increase the temperature in the shed, and then use the airtightness of the greenhouse to keep warm to ensure that the temperature in the shed is higher than the outside temperature. Because the greenhouse heats up quickly when there is sunlight during the day, and the temperature drops faster when there is no sunlight at night, resulting in a large temperature difference between day and night in the greenhouse, sometimes it gives people the feeling that the temperature in the greenhouse is quite low at night, which is just relative to the warmth of the day, not relative to the outdoor temperature. In addition, there is often more moisture in the greenhouse, and when the temperature drops at night, the humidity in the shed is larger, giving people the feeling of being wet and cold, and this distribution cold method is more thorough than the outdoor cold.

But if you measure it by temperature, the temperature inside the shed will definitely be greater than the temperature outside.

The indoor temperature of the greenhouse is colder than the outside, which means that there may be cloudy days, no sunlight for many consecutive days, the humidity in the greenhouse is larger, and there is no accumulated temperature, which may make the temperature in the shed lower. Or the greenhouse has been covered with curtains, has not received sunlight, and there is no accumulated temperature in the shed. But this is unlikely, because no one will cover the greenhouse with a curtain during the day in spring.

No matter what time it is, the temperature inside the plastic greenhouse must be higher than the outside temperature. The temperature in the shed rises and falls with the change of the outside temperature, or changes with the change of the outside sunlight. There is an obvious seasonal temperature difference and day and night temperature difference in the temperature in the plastic greenhouse.

In the current facility agricultural production in China, for the greenhouse that is used for uninterrupted production all year round, the most frequent use in summer cooling is the water curtain cooling system of Yueneng fan. So today I will share a few tips for using wet curtains.

First of all, we need to understand the composition and working principle of wet pads. Wet pad is a multi-layer corrosion-resistant paper material made of kraft paper after pressing and pasting, which has the characteristics of water absorption and rapid dispersion. The cooling principle is that the air passes through the water film of the wet curtain, and the unsaturated air absorbs most of the heat through evaporation to achieve the purpose of cooling.

Here are some tips for sharing.

1. The fan is closed for a delayed time.

The wet curtain works with the fan, and the negative pressure is formed in the fan exhaust shed, and the outdoor air is cooled by the water curtain to work. However, we tend to ignore that after the cooling of the wet pad is over, the fan should extend the working time so that the moisture on the pad can be dried and the service life of the pad can be prolonged.

Second, the filter cannot be ignored.

The water supply system of the wet curtain is generally used for water circulation in the circulating pool, and we need to install a filter on the upper water pipe of the water curtain to prevent impurities in the water from blocking our water curtain and affecting the cooling effect.

3. Installation of insect nets.

In the inside of the water curtain outward window, a high-density insect net is installed to prevent insects, dust, catkins and other foreign objects from entering or attaching to the wet curtain, which affects the ventilation and cooling effect of the wet curtain.

It is not ideal to rely on one aspect of the cooling of breeding greenhouses, and a variety of methods are needed to implement it together. The method of comparative science is roughly as follows:

1. Shading and cooling (recommended).

At present, the most commonly used in actual production is the shading system for cooling, which can block excess sunlight from the outdoors, protect crops from strong light burns, and create suitable growth conditions for crops. The sunshade methods are even more varied, some cover the shade net to cool down, and some pour mud and ink on the shed film to cool down.

2. Negative pressure fan + water curtain (highly recommended).

Negative pressure fans to achieve active ventilation and promote air circulation is a very good method, which can force the hot air to be discharged outdoors to actively achieve the effect of ventilation and cooling (in China: big herdsman, Tuhe, Jiafeng negative pressure fans, are the best in the industry). If you need to go further, you can further cool down by installing a cooling curtain.

3. Micro-mist cooling.

Micro-mist cooling is to spray water into the greenhouse in the form of micron-level or 10-micron-level fog particles to make it evaporate rapidly, take advantage of the characteristics of large latent heat of evaporation of water, absorb a large amount of heat in the air, and then discharge the moist air out of the outdoors to achieve the purpose of cooling.

4. Natural ventilation and cooling (recommended).

Natural ventilation generally refers to the setting of windows on the top or side wall of the greenhouse, relying on heat pressure or wind pressure for ventilation, and the amount of ventilation can be adjusted by adjusting the amplitude of the window.

5. Spray cooling on the roof of the shed.

Spray cooling on the roof of the shed is a cooling measure adopted by many farmers, but it also depends on its own water source.

6. Air conditioning and other equipment cooling (not recommended).

The use of air conditioning equipment is the best. However, the cost of this method is high, and the air conditioning system is rarely used as the greenhouse temperature control system. Collapse.