Temperature sensors for the greenhouse. Sensors in the greenhouse, the use of a thermostat. Compliance with the temperature regime in the greenhouse is the key to high yields

History and modernity

It is hard to imagine the gardening of our days, which would be carried out without the use of greenhouses and hotbeds. The temperature regime in the greenhouse makes it possible to have a set of your favorite vegetables and fruits in the refrigerator all year round and even enjoy the view of flowers in the very middle of winter.

The history of the invention of the greenhouse and greenhouse refers to XIX century when they started using them. These were pits covered with frames. These greenhouses were provided with heat by decomposing manure. Although such a design was primitive, it still helped even then to grow vegetables all year round.

In modern suburban area the greenhouse is one of the most important elements. A considerable part of gardeners come on weekends from their cities, where they mainly live, therefore, for such people, daily care of the greenhouse is difficult.

If you try to do without a greenhouse, the gardener will lose many advantages. Here, for example, greens planted in a greenhouse or greenhouse in early spring can be served at the table as early as May. If you grow your produce in a greenhouse, you will be able to harvest much earlier, and besides, your products will be at least as tasty as those grown in the traditional way.

When planning the purchase of a greenhouse, you need to think carefully so that your greenhouse does not end up being too expensive to maintain. Any gardener will want to have a high-quality and durable greenhouse. One of the most important criteria is strength, because this design must withstand strong wind and snow loads.

Aluminum greenhouses are the strongest and most durable (25 years), but the price bites, which is a considerable disadvantage. Greenhouses made of wood can last not so much time (10 years). Plastic greenhouses are the most unreliable and short-lived. Among gardeners, galvanized profile greenhouses are more popular: they have an adequate cost and, moreover, are quite durable. To cover the greenhouse, polycarbonate or film materials are most often recommended. Cellular polycarbonate is a resilient panel with air cavities that rolls up.

The advantage of the material is effective heat management: it protects the plants from overheating in the heat and does not allow heat to leave the greenhouse in the cold. Also, this material withstands the action of chemicals and blocks the path of ultraviolet radiation, which can harm plants. In addition, the installation process itself is not complicated and you can do it yourself.

It can be concluded that polycarbonate greenhouses are a fairly reliable choice in terms of sustainability and heat circulation management and more profitable financially. Due to the ability to withstand wind, severe frost and other harmful effects, a greenhouse made of such material will serve you for a very long time. In addition, this material does not lose transparency over time.

Back to index

Temperature controller in greenhouses

The temperature level in greenhouses must depend on the illumination (at night the temperature should be lower, and during the day - higher). The temperature controller, which operates from two sensors (temperature and light), meets all the requirements of a greenhouse temperature controller.

Back to index

The regulator has two main parts:

Temperature correction unit according to the level of illumination (transistors VT2, VT4);
Assembled on transistors VT6, VT8, VT10 temperature control unit.

Back to index

Temperature controller: circuit diagram

Electrical diagram of the temperature controller unit.

The matching device, made on the transistor VT5, connects these blocks. The temperature value you have set will shift as soon as the light conditions change, depending on the position of switch S1. With its contacts not shown in the diagram, the output relay K1 controls the operation of the heating device. In addition, it is the load of the VT10 power amplifier.

The sensors are represented by a thermistor R14 and a photoresistor R1 and are configured to react accordingly in case of temperature and light changes. The pairs supported by the combined controller make the setting according to the illumination with a variable resistor R2, according to the temperature level this is done by a variable resistor R15 and the temperature bias controller is a variable resistor R12. CT and RT blocks are based on Schmitt triggers. Diodes VD3 and VD7 are included in their emitter circuits to reduce the dead zone of triggers (hysteresis).

The output relay K1, which controls a powerful contactor to turn on the RPU-2 heater, has a response voltage of 24 V. There is also the possibility of using a reed relay of the RPG series, which has the same voltage. In the case of a relatively small indicator of switched power (several tens of watts), it is allowed to use the RES-32 relay (passport RF4.500.131 or RF4.500.163).

The power transformer was created using the ShL20x16 magnetic circuit. The primary winding has 3300 turns of PEV-2 wire - 0.1, the second winding - 350 turns of PEV-2 wire - 0.47, the third winding - 100 turns of PEV-2 wire - 0.21. Switches S1 and S2 - P2K, having a fixation in the pressed position.

If the temperature in the greenhouse is adjusted correctly, the average temperature should be from +16 to +25 degrees Celsius, and at night it should fall by no more than 5-8 degrees. Temperatures below normal will begin to slow down the growth rate of plants, and too heat is also not very favorable: it stimulates the growth of green mass, which will cause damage to plant yields and fruit quality in the greenhouse. It seems that everything is simple, hot weather in the greenhouse should help both tomatoes and palm trees in growth and yield. But it was not there. Just a few extra degrees above normal, and a large number of plants begin to wither. What is the reason?

The fact is that each type of plant has its own "favorite" temperature, and not only air, but also the soil. This is why it happens that under a certain regulation of the temperature in the greenhouse, one vegetable shows abundance in its harvest, while the second at the same time produces almost no fruit. For this reason, it is necessary to create special conditions for each individual group of seedlings. Here is a typical temperature control circuit:

The temperature of the air and soil in the greenhouse sets the pace of development by plants of the necessary nutrients. The more developed the root system of plants, the more correctly the organization is set. temperature regime in a greenhouse. If the temperature is less than 10 degrees Celsius, the process of assimilation of nutrients begins to slow down. For this reason, the soil temperature must be between 13 and 25 degrees, depending on the plant that is planted in this soil. For good development root system, the air temperature must be the same both at night and during the day.

Depending on what type of vegetables is grown, the daytime optimum temperature in the greenhouse is 16-25 degrees, and at night it is 4-8 degrees less. The growth rate of plants is directly proportional to the temperature, so if you increase the temperature by 10 degrees, the growth rate will also increase. But it is not worth raising the temperature excessively (over 40 degrees), as this will cause the death of greenery.

The most optimal temperature for the soil is 14-25 degrees. Reducing this temperature to 10 degrees will provoke phosphorus starvation of plants. Also, an excessive increase to 25-28 degrees can lead to difficulty in the absorption of moisture by the roots, for this reason there is a threat of wilting of plants even in moist soil.

The thermostat for greenhouses is necessary to ensure comfortable conditions for the growth and development of various crops. One installation of equipment that provides heating is not enough. The temperature to which air, water and soil are heated must be monitored and regulated around the clock. The fact is that, for example, during the day the temperature in the greenhouse should be higher, and at night it should go down. Accordingly, the mode of operation of the heating system must also change. It depends on external conditions, ambient temperature.

The thermostat in the greenhouse allows you to grow plants in any weather, providing a comfortable temperature.

Not only the air temperature inside the greenhouse should be controlled and regulated, but also the temperature of the soil in it. The ratio of these two parameters determines the intensity of growth and development of plants, since the activity of assimilation of nutrients by them directly depends on it. For most plants, the most comfortable are the following values:

for air 16-25°С;
for soil 13-25°С.

The need for temperature control and regulation also arises in summer. Security necessary conditions in this case, it is usually carried out using a controlled ventilation system.

The principle of operation of temperature control devices

The principle of operation of structures of this kind is quite simple: a signal is sent to the actuator, which, depending on the type of this installation, can cause the following reactions:

if it is a heating system, increase or decrease its power;
enable or disable forced ventilation;
open or close natural ventilation shutters for ventilation;
turn on or off the heating system of the soil and water for irrigation.

The occurrence of this signal is provided by a thermostat relay, which receives information from sensors installed in the greenhouse. A favorable microclimate for plants is determined not only by the ratio of temperature and light, but also by the amount of air humidity. For this reason, the most perfect system will be one that provides automatic regulation of parameters, taking into account the readings of three types of sensors: temperature, illumination and humidity. The following devices are most commonly used as sensors:

As a temperature sensor, the thermistor (thermistor) is most often used. In home-made designs, as a temperature-sensitive element, it is often used p-n junction semiconductor diode or transistor, since its forward resistance depends on temperature.
The light sensor is most often a photoresistor, but home-made designs sometimes use the same p-n junction, the reverse resistance of which strongly depends on the illumination. To access light to the junction, the cap of the metal case is usually cut off from the transistor, and the paint from the glass is washed off from the diode.
Industrial sensors of the third necessary parameter often use the humidity dependence of the dielectric constant of the medium between the capacitor plates. In addition, the change in resistance upon contact with moist air of substances such as alumina can be used. The fact of changing the length of a synthetic fiber or a defatted human hair with a change in the relative humidity of the air is also used, and so on. In home-made devices, such a sensor is often a piece of foil fiberglass with grooves cut into it. With increasing humidity, its resistance decreases.

Back to index

Types of industrial thermostats

Temperature controllers for greenhouses of varying degrees of complexity can be purchased at the appropriate stores, or assembled with your own hands (if you have the necessary skills).

Today, three types of models of these devices are produced:

Touch temperature controllers are quite expensive multifunctional systems. Designed primarily for large greenhouse complexes. It is possible to set a variety of programs that control the operation of the heating system. They can even take into account the release of heat from decaying manure. They have a wide variety of functions, usually equipped with a backlit display.
Electronic thermostats are devices, the number of functions of which is noticeably less than that of the regulators of the previous class, but the price is correspondingly lower. Usually equipped with a switch that allows you to set a specific heating mode. For convenience, they are often supplemented with a liquid crystal display with the necessary information.
Mechanical thermostats are the simplest in their design, but often no less effective devices than their electronic counterparts. It is not economically feasible to purchase, for example, expensive equipment for a small country greenhouse. But an inexpensive mechanical thermostat for her would be the most suitable option.

When purchasing any of these devices, you should pay special attention to their characteristics:

power of the serviced heating installation and its capabilities;
specific settings that may be required;
whether this device has all the required functionality;
ease of use and suitable appearance.

In industrial greenhouses, a whole system of sensors monitors the stability of the microclimate. In private buildings, plants have to be saved from heat or cold manually - by ventilating or regulating the heating system. Round-the-clock service is not only tedious, but also tightly ties the summer resident to the beds, so sooner or later he has to think about whether it is possible to make a thermostat for the greenhouse with his own hands, and how reliably it can function.

It would seem, why not purchase a ready-made device, because many models are offered on the market today, the price of which starts from 400 rubles? In fact, branded controllers, the reliability of which can be trusted, are expensive, and cheap analogues can fail at the most crucial moment, which is fraught with the loss of the entire crop.

By assembling and testing the thermostat with your own hands, you can save money and be safe from its failure.

Automatic thermostat from the manufacturer

How to achieve the main goal - adjusting the temperature inside the greenhouse in automatic mode? The easiest way to do this is to open and close the windows at the right time.

Timely ventilation helps to keep the air temperature in a certain range, comfortable for the normal growth and fruiting of cultivated crops.

Many devices have been invented to automatically open the windows: some of them are made from improvised materials - plastic bottles, empty cylinders; for others, you need to stock up on some parts in advance, for example, an automobile gas shock absorber. In both cases, the price of the device is minimal, but the level of its operation will need to be checked quite often.

Ventilation - the usual way of thermoregulation

Classic greenhouse thermostats, if necessary, limit the access of the coolant to the heating elements or, conversely, contribute to a rapid increase in temperature. Thus, hypothermia and overheating of plants are excluded, and excess energy is not consumed. This significantly reduces the cost of heating the greenhouse, so this method of controlling the microclimate is preferable.

Their principle of operation, regardless of the type, is to process the readings of one or more temperature sensors and transmit a signal to the actuator of the heating system, which then either reduces the power of work or increases it.

To create such a thermostat for a greenhouse with your own hands, you need knowledge of electronics and skills in assembling electrical circuits.

Homemade thermostat assembly

Video: How to assemble the thermostat yourself

Installation of thermostatic devices - mechanics and electronics

Ideally, when thermostats complement the operation of fanlight thermal actuators: in winter they turn off and turn on heating, and in summer the microclimate is controlled by opening and closing the windows. Thus, a summer resident can devote much less time to his greenhouse without fear for his crop.

Pneumatic thermostat - removal of excess heat

The pneumatic device, whose action is based on the ability of hot air to expand, is elementary in assembly and at the same time allows solving the problem of thermoregulation for a long time. For its installation, the following elements are required:

2 cans of paint with a capacity of 5–7 liters (with lids);
several tubes from medical droppers;
children's inflatable ball with a coverage of about 300 mm;
thin plywood with a width of at least 300 mm;
metal strips (strips) of any size;
3 copper tubes 50 mm long.

Schematic diagram of the pneumatic regulator

Assembling a thermal drive consists of a few simple steps:

Seal the cans by soldering or potting with epoxy.
Drill one hole the size of the copper tubes in one container and two in the other.
Insert the tubes into the holes and seal the joints.
Make a plywood box measuring 300x300 mm. Leave it open on both sides.
Cut the plywood plate to the dimensions that correspond to the cavity of the box as much as possible.
Insert the plate inside the box and fix it with loops.
Attach the box with the open part to the window.
From two metal strips, make a movable lever, one shoulder of which is rigidly attached to the window, and the second to the movable plate of the plywood box.
Close the window and check the position of the plate - its angle of inclination relative to the walls of the box should be 45 degrees.
Hang tin containers under the roof and connect them with tubes from droppers, while the length of the outgoing tube should cover the distance from the cans to the box.

It is necessary to close the entire system into a single mechanism in cool weather or in the evening. To do this, you need to put the ball in the box and inflate it exactly until the moment when, with further air injection, it begins to open the window.

After that, it is necessary to tightly connect the end of the outgoing tube with the ball and check the operation of the device when it warms up.

Pneumatic system in another design

gas shock absorber thermostat

Having slightly modified the pneumatic shock absorber from any passenger car (these are usually placed on hoods or rear doors), you can get a device that can automatically open a transom or window, thereby eliminating excess heat energy.

The spare part does not have to be new - it is enough that pressure remains in it. You also need to stock up on a brake hose and an empty car fire extinguisher in advance.

You can mount these parts in a single device in this way:

Without violating the tightness of the pneumatic cylinder, cut off the spherical part of its shank, leaving the maximum length.
From the side of the formed end, drill a hole with a diameter of 2–3 mm to bleed air from the cylinder cavity.
Cut the thread on the shank (its pitch depends on the size of the thread on the existing brake hose).
From a fire extinguisher (or a car cardan with a volume of 3 liters), build an oil reservoir with a connecting hole for a hose.
Pour oil into the shock absorber and reservoir, then connect them with a hose.

After installing the thermostatic system, test its functionality by temporarily increasing the heating output.

Homemade pneumatic regulator in the greenhouse

The wonders of electronics - assembling a regulator from a household thermometer

To get at your disposal a thermostat for a greenhouse, which controls the air temperature in a constant mode and transmits a signal about the need to change the operation of the heating system, you need to modify a conventional pointer thermometer:

Disassemble the temperature sensor so as not to damage it.
Drill a hole with a diameter of 2.5 mm in the scale - in the area of \u200b\u200bthe required temperature limit.
Opposite it, construct a corner of thin tin with a 2.8 mm hole drilled in it.
Install the phototransistor in the socket of the corner and attach them to the scale using Moment glue.
Under the hole, fix another corner that prevents the arrow from moving when the temperature rises.
On the opposite side of the thermometer, install a 9 V light bulb. You can put a lens between the scale and the light bulb - this way the device will more accurately respond to the indicators.
Lay the wires of the photocell through the central hole of the thermometer scale.
Drill a hole in the housing for the light bulb wires. Thread the tourniquet into the vinyl chloride sheath and secure with a clip.
According to the standard scheme, assemble a voltage stabilizer and a photo relay with a GT109 transistor.
Place the photorelay, power supply and temperature sensor on the basis of the factory relay mechanism.
On the outside of the common body, fix a toggle switch and a neon light to signal the start of heating.

Pointer thermometer for greenhouse

A do-it-yourself thermostat for a greenhouse works on the principle of an electromagnet: a steel anchor is pulled into a coil, and a switch (with a current of 2 A and a power of 220 V) activates an electromagnetic starter that supplies power to the heating devices.

Thermostat assembly diagram

The main disadvantage of an electronic thermostat for a greenhouse is its dependence on a source of electricity. If the electricity goes out in extreme heat or cold, you can lose all the plants.

The temperature regime, which is formed and regulated by several systems at once - heating, ventilation, air humidification, evaporative cooling and others - plays a major role.

For constant control with the possibility of adjustment, the air temperature controller in the greenhouse is used, which is an important element, since even a slight change in indicators can adversely affect the plants, up to their death.

Compliance with the temperature regime in the greenhouse is the key to high yields

As a rule, for most plants, the most comfortable temperature is within from 16 to 25 °C, and a deviation of even a degree, if it does not lead to the death of plants, their appearance will be very eloquent: in this case, the symptoms of wilting begin to appear.

It is important to regulate not only the air temperature in the greenhouse, but also the soil temperature. The interaction of these two indicators determines the rate and intensity of the assimilation of nutrients from the soil, respectively, they directly affect the growth and development of plants.

The optimum soil temperature is in almost the same range as 13 to 25 °C and is determined, as a rule, by what kind of crop is grown.

Attention! Temperature differences in the soil are sometimes even more noticeable for plants. For example, a decrease slows down or stops vegetation, and an increase affects the absorption of moisture by plants.

Methods, methods and devices for temperature control in a greenhouse

The most convenient option: to make automatic temperature control in the greenhouse, taking into account the readings of sensors connected to all systems. For this, various models of automatic regulators are used.

Some of the modern models have the ability to program:

for a specific type of plant;
under day and night modes;
with the possibility of sms notifications, etc.

On such models, all information is displayed on the scoreboard, and making adjustments, programming or reprogramming is carried out easily and quickly, thanks to an intuitive menu.

Advice. It is economically unprofitable to buy an expensive system in private ones. In this case, for example, a mechanical apparatus or a home-made temperature controller in a greenhouse can be successfully used, which, meanwhile, successfully cope.

How to choose the right thermostat

A properly selected regulator (thermostat) must take into account several factors.

The power of the device, which should be:

sufficient and correspond to the power of the heating system;
fit the size of the greenhouse;
be completed with or compatible with sensors and their number, which is required.

Ease of installation and operation:

functionality of the device:programming; control; control of current parameters;degree of autonomy.
timing of installation work.

How the thermostat is arranged and works

Any thermostats for - temperature control unit based on the readings of the connected sensors. Such a device can be assembled independently. For this, a thermostat scheme for a greenhouse can be used, presented in professional literature and on specialized sites on the Internet.

All thermostats, even assembled with their own hands, work according to the following principle: a signal processed on the basis of sensor readings is sent from the device to the system, for example, heating, to increase or decrease power.

How to properly set up the device

For a self-assembled device using sensors, a so-called setup process must be carried out. In this case, the instruction must be clearly followed, according to which the process is reduced to grading the scale of the resistor.

The essence of the adjustment is as follows:

sensors are placed in heated water with a known temperature;
based on the data, the scale is calibrated and synchronized;
after that, the sensors can be installed and connected to the thermostat.

A simple, affordable and efficient way to control temperature

For summer residents who have greenhouses on their site, but visit them only once a week, it is rational to assemble a device, the price of which is much lower compared to industrial counterparts. However, such devices meet all the requirements for them, they are reliable and accurate.

Solar energy serves as a power source for them, and air acts as a sensor. The regulator is a housing divided into sectors made of duralumin, an inspection cover with a pusher link and a rotary valve.

Next is an expansion tank connected to a rubber chamber, for example from a ball. When the air is heated above 25 ° C, the chamber is filled, which, in turn, opens the transom of the greenhouse to the appropriate width. When the temperature drops, the reverse process occurs.

How to quickly change the temperature in a greenhouse in an emergency

It is often necessary to regulate the temperature in greenhouses, especially in small home or summer cottages, by some other available methods.

As a rule, such measures are relevant when there is an urgent need to raise or lower temperatures, for example, during the off-season.

The temperature can be easily raised, for example, by one of the following methods or in combination:

covering with an additional layer of film,
the use of a portable structure, under which plants are sheltered in the greenhouse itself,
use of means for covering the soil, such as manure, film, etc.

Measures such as:

provide access to fresh air in sufficient quantities;
spraying the greenhouse with a chalk solution;
in the summer, water and spray plants early in the morning, immediately after sunrise.

Conclusion

For each greenhouse, the calculation and scheme of temperature controllers must be done separately, depending on the design of the room, heaters, fans and crops to be grown. Some options can be seen in the video in this article.

Not one even the most well-built greenhouse will be able to perform its main function, growing plants, without the correct temperature regime. Today we will talk about the temperature regime in the greenhouse.

At the very beginning of our article, we want to say right away that the yield of plants is affected not only by the air temperature in the greenhouse, but also by the temperature of the soil (see Earth in the greenhouse: soil selection and care).

It is important to understand that various plants grow well and bear fruit strictly at a certain temperature.

Different plants - different temperatures

Many probably faced such a question that in a certain year some plants gave a rich harvest compared to other plants growing nearby.

It's all about the temperature, for some it was the most optimal, and for others it was either too high or too low.

Greenhouse - temperature advantage

But if on open ground temperature control for individual plants is not possible, then the greenhouse is a closed space in which it is possible to successfully regulate the temperature regime.

Proper placement of plants is an important task

That is why it is so important to properly plant plants in a greenhouse. If your greenhouse is large, then there will be a significant difference in temperature in various parts of it.

This can be successfully used by planting heat-loving plants in warmer places, and in cooler places, plants for which given temperature is optimal. For more information on how to grow different crops together, you can read: Peppers and Eggplants in the Same Greenhouse and Growing Cucumbers and Tomatoes in the Same Greenhouse).

temperature fluctuations

As in the open field, in the greenhouse there is a temperature difference between day and night. This difference is very important. Too large fluctuations can adversely affect plants and lead to their diseases, and in some cases even death.

Our reference - the limit of night and day mode should not exceed 4 - 8 ° С.

What is good for greens is bad for the fruit

Depending on the type of plants, the daily air temperature in the greenhouse should be 16 - 25 °C. Temperature directly affects growth, for example, a temperature increase of 10 ° C will increase the growth of greenery.

Do not rejoice, the roots and fruits at the same time develop much worse.

An increase to 40 ° C leads to a depressed state and possible death of the entire plant.

We were talking about air temperature.

Air is important - soil is just as important

The temperature regime of the soil is also important and should be within 14 - 25 ° C, everything also depends on the type of plant.

If the soil temperature drops and reaches 10 ° C, the plant will begin to experience phosphorus starvation.
Too high a temperature, exceeding 25 ° C, leads to difficult absorption of moisture by the roots.
With the right temperature regime, the root system of plants develops and functions correctly, which cannot affect the well-being of the whole plant.

temperature issue

Realizing that the temperature regime in the greenhouse is extremely important and the yield depends on it, many will wonder how to control the temperature and observe the most optimal regime in the greenhouse?

Automatic regulation - the solution to the temperature issue

As is clear from the above, visual compliance with all parameters is a very difficult and responsible task.

Therefore, the surest option would be to equip the greenhouse with automation.
Automatic temperature control in the greenhouse will relieve you of the worries of hourly control and measurement of air and soil temperature parameters in various parts of the greenhouse.

Sometimes the temperature begins to rise above the required norm, and at this time you are not.

How to lower the temperature in the greenhouse to the required parameters?

Automation comes to the rescue. Currently, there are a large number of various electronic devices on sale, which we have already discussed earlier (see Thermoregulator for a greenhouse).

We build a temperature controller ourselves

But it is not necessary to purchase temperature control devices with electronic filling, such a device can be built by any person, even far from knowledge of electrical engineering.

Physics to the rescue

Today we will build a device that uses a simple law of physics - when heated, a substance expands in volume.

So, how to lower the temperature in the greenhouse using a homemade, simple device?

Materials - all from the farm

It is quite easy to make it at home. We will need:

Three liter jar 1 pc.
Liter jar 1 pc.
Copper tube with a diameter of 5 - 6 mm.
Lid for cans metal (for seaming) 1 pc.
Lid for jars polyethylene 1 pc.
Rubber hose (a hose from a dropper works well). The main condition is that the hose should fit tightly on the tube, be flexible and not be pinched.

Tool minimum

From the tool we need:

Soldering iron.
Seat for cans.
A hammer.
Pliers.
Thermometer.

Stage one - we make a thermosyphon

You can get to work.

Roll up a three-liter jar with a metal lid.
Drill a hole in the center of the cover of such a diameter that the copper tube fits snugly into the hole.
Insert the tube into the lid so that it does not reach the bottom of the jar by 3 - 5 mm.
While holding the tube in this position, solder it to the cap. The connection must be tight.

Calibrating the device

Our thermosyphon is ready. Before performing a complete installation of the entire device, it is necessary to check our siphon and obtain accurate data on its operation.

This is done as follows:

Pour a liter of water into a three-liter jar through a tube.

Our advice - understanding the complexity of pouring water through a tube with a diameter of 5 - 6 mm, we advise you to do the following. Pour a liter of water into the container. Put a hose on the tube and turn the jar upside down.

Suck the air out of the can through the hose, pinch the hose and lower its end into the collected water. Release the clamp. The water will go into the jar.

After performing this action several times, you will pump the required amount of water into the jar. Thus, later on, water is added to the device.

Place the jar in a bucket and fill it with water to such a level that the water does not reach the lid of the jar by 50 - 70 mm.
Put a hose on the copper tube, and lower the other end into a liter jar.
Put the bucket on the fire and heat the water, while controlling its temperature with a thermometer.
When the water in the bucket begins to heat up, the air and water in the jar will heat up.
The created pressure will begin to push water out of the three-liter jar, it will begin to flow through the hose into the liter jar.
When the temperature reaches 25 ° C, the fire must be turned off and the amount of water that has entered the liter container must be measured, this volume will be approximately 400 ml.

Principle of operation

You can collect our device. The principle of its work has already become clear.

When the temperature inside the greenhouse starts to rise, their water three-liter jar will begin to flow into the liter, which in turn plays the role of a counterweight.

Thus, an increase in the mass of a liter jar opens a window and ventilates the greenhouse. The higher the temperature, the more water arrives and means, the window opens more and more.

When the air temperature in the greenhouse begins to drop, a vacuum is created in the three-liter jar and the water from the one-liter jar is sucked back. Thus, the mass of a liter jar becomes smaller, and the window begins to close.

Assembly and installation

As you can see, the temperature controller for the greenhouse turned out to be quite simple, but nevertheless very effective.

A liter jar is hung from the window.
A plastic cover is put on it, in which a hole is made and a hose is inserted there. The end of the hose does not reach the bottom by 3 - 5 mm.
200 ml of water is poured into a liter jar.

Weight adjustment

The only thing to do is to choose the right counterweight for the frame.

Everything is done by experience.

The weight of a liter jar and the water poured into it should not open the window.
But when water from a large jar begins to flow into a small one, the window should open.

Important - the cavity of a liter jar should be freely connected to atmospheric air. If the hose fits snugly in the plastic cover, make a hole in the cover next to it.

This system does not require special control. The only thing that needs to be done is to add water to a three-liter jar, the volume of which decreases due to evaporation.

Tomatoes, eggplants, cucumbers, strawberries - we solve the temperature issue

This unit is adjusted for tomato, but it can be adjusted to your desired temperature.

For example, the temperature for cucumbers in a greenhouse is different from the temperature regime for a tomato (see How to grow cucumbers and tomatoes in a greenhouse). During the germination period, the optimum temperature is 25 - 28 ° C.

With further cultivation, it is very important to ventilate the greenhouse on sunny days, while the temperature is 28 - 30 ° C, and on cloudy days it should fluctuate around 20 - 22 ° C.

This device will successfully cope with this task.

If you require that the temperature in your greenhouse does not exceed 20 ° C, adjust the device for this temperature regime. How to do this you probably already understand.
Make the counterweights removable and specify the temperature range for each, then you just need to change the counterweights, and the temperature in the greenhouse will be adjusted strictly according to the specified parameters.

Our advice is to put a water level mark on the jars, so it will be easy for you to determine the moment when you need to add water to the device.

By applying ingenuity and a system of levers, it is possible to make it possible to open several windows at the same time with this device.

Today we talked about how to build a temperature controller in a greenhouse on your own in just a few hours. At the same time, we did not need to get expensive and rare materials, we simply took advantage of what is always available in any household.

Air regulates temperature

Such devices are successfully used by many gardeners.

There is a device that works this principle but it uses air instead of water.

The device and principle of operation of the air regulator

It is arranged as follows.

Instead of a three liter jar, a metal container is used there, preferably aluminum. The container is sealed.
By increasing the temperature, the volume of air in the container increases and the air begins to flow through the hose into the rubber chamber. With success, you can use the camera from a soccer ball.
The camera expands and pushes the lever, which opens the window.

As you can see, the system is closed, sealed and does not communicate with the atmosphere..

As the air temperature in the greenhouse drops, so does the air pressure in the device.
The rubber chamber deflates, the lever moves back and the window closes.

Advantages and disadvantages

The advantage of this system is that it does not require control over the water level and works independently for a very long time.

Among the shortcomings, one can single out the fact that good tightness is required. Otherwise, the device simply will not work, and visually identifying a leak is quite difficult.

There are many ways to control - choose according to your liking

We have described several ways independent solution automation of your greenhouse. It's up to you to decide which method to use.

The most important thing is that you understand that the greenhouse, the temperature and humidity in it, directly affect the yield and health of your plants.

Good luck and a rich harvest!