Bert van Tol of Sendot contributed to the 10th Grodan International Propagation Seminar by presenting several applications of sensors in propagation. A Photosynthesis Efficiency sensor is an invaluable tool for optimizing growth strategies, especially when such a sensor can be integrated into the process. Applications in Phalaenopsis growth have demonstrated that not only plant quality control can be achieved, but also energy savings can be realized. Increasingly, various applications of this tool prove it’s added value for gaining insight into plant behavior. In propagation, a photosynthesis efficiency sensor can be used to optimize watering and lighting strategies. Recent experiences have shown that controlling the lighting strategy for tomato propagation reduced the number of blind tomatoes.