Greenhouse Automation: Climate Control Systems Explained
Basics4 minInnovialabs editorial team
In short
A climate control system measures air, substrate and light with sensors, and a controller follows set rules to run vents, heating, fogging, grow lights and fertigation — all visible and adjustable from a phone.
What greenhouse climate control is
Climate control is a chain of sensors, a controller and actuators. Sensors measure what is happening inside. The controller compares readings with target values (setpoints) and decides what to switch on. Actuators — vents, fans, the boiler, screens, lamps, pumps — change the conditions.
The main value is stability. Plants suffer less from a "wrong" temperature than from sharp swings and from a person noticing a problem too late. Automation reacts immediately, day and night, and logs everything that happened.
Which parameters are controlled
| Parameter | Measured with | Controlled by |
|---|---|---|
| Temperature | Air sensors in aspirated housings, sometimes leaf sensors | Heating, vents, fans, screens, evaporative cooling |
| Humidity | Relative humidity sensors, calculated VPD (vapour pressure deficit) | Fogging, ventilation, heating |
| CO2 | NDIR CO2 sensors | CO2 dosing from tanks or a generator, limited while vents are open |
| Lighting | PAR or light sensors, outdoor weather station | Supplemental lighting, shade screens |
| Fertigation | EC and pH sensors in the solution, substrate moisture, drain | Dosing pumps, irrigation zone valves |
Fertigation means irrigating and feeding at the same time. The unit mixes concentrates, controls EC (salt concentration) and pH, and delivers solution to zones on a schedule or based on accumulated light: the more light the crop received, the sooner the next irrigation.
How the parameters affect each other
The hard part is that parameters are linked. Open the vents to cool down and humidity drops and CO2 escapes. Turn on fogging and humidity rises, but with poor ventilation disease risk grows. That is why good controllers do not act as separate thermostats but run strategies:
- day and night modes with smooth transitions at sunrise and sunset;
- priorities, for example overheating protection beats keeping CO2 levels;
- outdoor weather — wind, rain, solar radiation — from a rooftop weather station: in strong wind, windward vents stay closed;
- rate limits: vents open in steps, not all at once.
What the system consists of
- Sensors inside and outside. How many depends on area and uniformity: one sensor is not enough for a large greenhouse.
- Controller — a dedicated greenhouse computer, an industrial PLC or a simpler controller for small farms.
- Actuators with motors and relays.
- Connectivity: wired buses (Modbus RTU, RS-485) inside, Ethernet, Wi-Fi or LoRaWAN for sensors, cellular for internet access.
- Software: settings interface, charts, event log, alarms.
A key principle: the controller must work on its own. If the internet drops or a cloud service fails, the greenhouse keeps running on the last setpoints. The cloud is for monitoring and analysis, not real-time control.
Remote monitoring
What is usually available remotely:
- live readings and charts for a day, week or season;
- alarms via a mobile app, SMS or a Telegram bot: overheating, power loss, pump failure, EC out of range;
- changing setpoints and manual control with confirmation;
- comparing several greenhouses or zones;
- data export for the agronomist.
Decide who receives alarms and what happens if they do not respond. An escalation chain — a second person after a few minutes — often matters more than a nice dashboard. You also need a backup channel: a power-loss sensor with its own battery and a separate SIM card.
How to implement it
- Start with an audit: which equipment already exists, what is done by hand, where crops are most often lost.
- Automate in layers: monitoring and alarms first, then temperature and ventilation, then fertigation and CO2.
- Calibrate sensors on a schedule. A cheap uncalibrated humidity sensor produces confident but wrong decisions.
- Keep a manual mode for every actuator in case of failure.
- Choose open protocols so you can add other equipment or your own analytics later.
Common mistakes: sensors in direct sun without shielding, one sensor for a huge area, no backup power for the controller, setpoints copied from the internet without regard to crop and variety.