My Cart

Frequently Asked Questions & Tips



VPD stands for Vapour Pressure Deficit.

This value is calculated from the leaf temperature and humidity. For an optimal metabolism of the plant, VPD has an even greater influence than temperature or humidity per se.

With GrowBase Pro the vapor pressure deficit can be controlled automatically.
To determine the leaf temperature, our leaf temperature sensor IRCube can be used, or a difference to the room temperature can be entered.


The transpiration of your plants is determined by the VPD value.

The transpiration determines how fast the plants' metabolism runs and to what extent new water and nutrients can be absorbed.

Only at optimal VPD values is it possible for your plants to grow and mature optimally by absorbing light, nutrients and CO2.


Too low VPD values lead to insufficient transpiration.💦 As a result, the plants absorb less new water and nutrients, and metabolic processes slow down, inhibiting growth.

Too high VPD values lead to stress for your plants.🥵 Transpiration is too high, the stomata become small and the plants cannot take up the available CO2 to use it for photosynthesis.


Which VPD value is optimal depends on the stage (propagation, vegetation, flowering) of the plant.

The following values can serve as a reference:

4-8 hPa
Low transpiration (propagation / early vegetation)
8-12 hPa
Healthy transpiration (late vegetation / early flower)
12-16 hPa
High transpiration (mid-flower / late flower)
Below 4 hPa / above 16Dangerous zone

These values should serve as a rough guide and are mentioned in the literature. You will certainly not make any major mistakes with these values, but they are not absolute values. There may be good reasons to choose significantly different values. The topic is the subject of current research and previous findings can be updated.


The upper limit for the respective setpoint temperature of the heating is "setpoint room temperature" MINUS 1°C.

This applies in each case for day/night/CO₂.

To increase the upper limit for the heating setting, the respective room setpoint temperature must therefore be increased.

This is done to avoid heating and cooling by ventilation/air conditioning at the same time.


[k] bedeutet kilo (tausend)

[h] steht für hekto (hundert)


0.80 kPa corresponds to 8.0 hPa (i.e. x10)

6.5 hPa corresponds to 0.65 kPa (i.e. /10)

For the conversion, the decimal point only needs to be moved one place to the right or left.



All LED lights with a 0-10V or a 1-10V input can be connected.

For some LED lights we offer ready-made cables.

However, other luminaires can also be connected. The pin/cable assignment of the luminaire must be known. The pin assignment of our controllers is shown in the manual.


An LED light with a 0-10V input will turn off completely when the signal drops below 1V.

Accordingly, the supply voltage of the LED does not have to be switched off to turn it off.

An LED light with 1-10 V input remains dimmed to 10% even if the signal drops below 1 V.

To switch off 1-10V LEDs completely, the supply voltage of the LED must be switched off. This is where the 4th socket of our GrowBase Pro comes into play, as it is optimized for switching LEDs.



The measured speed (rpm) is only displayed if the EC fan used provides a corresponding signal.Whether the signal is transmitted depends on the respective EC fan. In addition, the cable used must also transmit the speedometer/rpm signal. This value is for information only and has no influence on the function.


To control EC fans, a controller for EC fans is required.

The power supply of the EC fan is connected to a normal power socket. The speed adjustment and the switch-off are only controlled via the 0-10V signal from the controller.

If an EC fan is connected to a socket that is designed and set for AC fans, it will not work and the fan and controller may break.


The power supply of the EC fan is connected to a normal socket. Speed adjustment and switching off is only done via the 0-10V signal from the controller.
A positive side effect: An EC fan does not occupy a socket on the controller.

If an EC fan is connected to an outlet that is set to "AC fan", it will not work and the fan and controller may break.

In order for the EC fan to be operated with a controller, it must have a corresponding input. We offer cables and adapters that can be used to connect all common EC fans.

In addition, the EC fan must be voltage controlled. Fans that have built-in temperature control usually cannot be operated with a controller.


For new acquisitions, we definitely advise EC fans!

The speed of EC fans can be controlled without any hum. In addition, the speed can be reduced to 10%, which is not easily possible with AC fans.

An EC fan always consumes only the energy that corresponds to its speed/load. Therefore, the somewhat higher initial costs are recouped after a short time.


GrowBase Lite, GrowBase and GrowBase Pro are equally suitable for controlling EC and AC fans.

FanBase EC+ is only suitable for EC fans.



Without special laboratory equipment, it is easy to calibrate the sensor or sensors in fresh air.

For this purpose, the sensor can be placed e.g. at an open window.
The CO₂ concentration in the earth's atmosphere is 400 ppm. Fresh air in a city is between 400 and 450 ppm.

The calibration procedure is described in the manual.

Short version:
1. set filter to 7 & transfer
2. place the sensor in fresh air for a few minutes
3. set calibration value & transfer
4. set filter to desired value again and transfer (recommended: 0)


If all factors (climate, lighting, nutrients etc.) are optimal for the plants, the factor that limits an increase in the photosynthesis rate is the CO₂ content of the air.

You should therefore have all these factors well under control so that the CO₂ addition can have its full effect.

With GrowBase Lite, GrowBase and GrowBase Pro, the CO₂ content of the room air can be controlled and thus a considerable increase in yield can be achieved.

Advanced settings & expert topics


The control type for the humidifier can be set in the "Advanced settings" menu area.
Control type "P" should be selected here so that the humidifier is switched infrequently.
In addition, the hysteresis for the humidifier can be set in the "Advanced settings" menu area if required. The greater the hysteresis, the less frequent the switching.

To install this Web App in your iPhone/iPad press and then Add to Home Screen.

Added to cart