Vapor Pressure Difference (VPD) is an important instrument to recognize and prevent plant stress. The plant temperature sensor measures the plant temperature using infrared radiation. The sensor determines the average temperature of a given surface of the crop, so that the measurement is stable and reliable. The iSii process computer uses these measurements to calculate the VPD and determine whether the plants are stressed. With this information the iSii process computer can optimize the climate and irrigation controls.

As a grower you constantly try to achieve a homogeneous climate, because large temperature differences increase the risk of crop condensation. In order to prevent this it is important to have insight into temperature differences in the greenhouse and temperature differences between the plant and the environment. Thermoview real-time measures the temperature of the plant and its fruits, flowers and environment with one sensor. The intelligent software determines the hottest and coldest spots in the crop and sends a notification when the fruit or flower temperature is too hot or too cold. These insights enable a grower to adjust the climate controls in order to optimize the growth climate and avoid crop condensation, crop damage and diseases. The Thermoview data can be integrated with the climate data from the iSii process computer, which allows you to calculate the dew point.

Download the Thermoview whitepaper

PAR (Photosynthetically Active Radiation) light, or grow light, is the part of the light spectrum that the plant requires for photosynthesis. Photosynthesis is the plant process in which CO₂ and water are turned into glucose. The PAR sensor allows the iSii process computer to optimize the controls for lighting, CO₂ dosage and shading screens, among other things. By optimizing these controls an optimum growth climate can be realized.

The HGM Balance is the first step for growers who want to optimize their irrigation strategy. The HGM Balance is a scale that accurately monitors the weight of the substrate and/or crop, in order to obtain information about the irrigation requirements of the crop. With these insights you can plan your irrigation cycles carefully. After all, you don’t want your crop to receive too little or too much water.

The measured data can be displayed in graphs on the iSii process computer, to show you the irrigation requirements of your crop during the whole day and night.

Optimum irrigation in substrate cultivation is a complex process. With strong plant evaporation due to high levels of radiation, the plant must have sufficient water. In addition, the substrate must be flushed to prevent the accumulation of nutrient elements. At low evaporation rates and at night, the slab dehydrates, allowing air and oxygen into the root zone. Hoogendoorn developed the Aquabalance to take on this challenge. Aquabalance is a special sensor that determines the plant’s water requirements in order to align irrigation precisely. It consists of three main components: precise scale with a standard length of 3 meters, a reliable drain measurer and intelligent software in the iSii process computer. Since Aquabalance tracks the water uptake of the crop precisely and starts a new drip cycle at exactly the right moment, it is in fact the crop itself that regulates the irrigation according to its own needs.

Optionally the Aquabalance can be extended with sensors to measure and register the EC (nutrient concentration) and pH (degree of acidity) of the drain water. Also, if you have a HGM Balance this can easily be upgraded to Aquabalance.