Measuring Homogeneity at Vereijken Kwekerijen (Vereijken Nurseries)

Between Eric Vereijken’s, of Vereijken Kwekerijen (Vereijken Nurseries), tomato plants there is a small, blue box: a sensor that forms part of the AgriSensys-system from Wireless Value. Every five minutes the humidity and temperature in the greenhouse is monitored. In total there are 27 sensors. “In a week there are 168 hours, in a work week only forty”, Vereijken explains. “Deviations creep in easily. The more equal the climate in your greenhouse, the easier the growing.”

Vereijken Kwekerijen (Vereijken Nurseries) grows Camparis in 35 hectares locations, which are marketed as Tasty Toms. Eric Vereijken works with the wireless sensor system AgriSensys from Wireless Value. In his greenhouses 27 sensors are installed, which measure the humidity and the temperature every five minutes. The information of the sensors is made insightful with various graphs at the base station. The development of the humidity and the temperature can be viewed online, as can any diseases in the greenhouse. This can be adapted to the desired period. “If you are going to really immerse yourself in it, it will take you a while,” Vereijken admits. “The aim is to eliminate as many variations as possible from the greenhouse. Our tomatoes can quickly grow too big, especially if you have a cold corner in the greenhouse, and then we can’t sell them as Tasty Toms,” he continues. “At the beginning of the growing, you can see clearly what is happening to a plant, but later deviations can easily occur. Especially at night when it is more difficult to keep an eye on what is happening. Only afterwards can you usually see where the differences were and which plants grew better. This is something you want to prevent and now you have the data for that.” Measuring the homogeneity of the climate is important because in this way you can achieve maximum production.

Bas Visser of Wireless Value confirms Vereijken’s story. He notices that both in old as well as in new greenhouses the system is used and there is a lot of interest within the New Cultivation as well. “The more equal the climate is, the more energy efficient heating is and the better the production. And it is not that much work to install 25 sensors,” he refers to the optimal measuring situation that was established by the WUR: 25 sensors per hectare.” The lower limit is around ten sensors per hectare. Yet, Vereijken manages with 27 sensors for an area of 35 hectares. “We often lug them back and forth,” he explains. “If we see a corner that deviates too much, we make compartments.” In this way the net is reduced and wherever the problem is soon becomes visible.