How will we grow healthy tomato plants in the future? By letting some of them die today. “We want to be able to predict much earlier that a plant is deteriorating, which is why we measure how the process of stress works,” explains Thijs Bieling, co-founder of Plense.
To understand how such a measurement is carried out, we need to get acquainted with the technology developed by Plense first. This Delft startup develops hardware and software for horticulture. Plants have vessels that moisture flows through. The lack of moisture causes ultrasound. This is not audible to humans, but a special microphone can capture this sound. In recent years, Plense has specialised in recognising and interpreting these sounds: “We map how the plant is holding up and whether it stays within a crucial limit”.
Thijs explains: “We started by merely listening to plants. A plant produces a specific sound when it is stressed. However, you want to know in advance if the plant gets stressed, so you can make corrective adjustments at an early stage before a certain stress level is reached. In other words: if a plant is not doing well, you are already too late. We want to be able to see: in 1 hour those noises will emerge”.
“One of the ways we can do that is by directing a speaker at the plant and emitting the same kind of sounds. In essence, we talk to a plant and listen to what it responds. If you watch how the sound forms, you get information about what is happening inside the plant. The principle is similar to an echo, which is used in hospitals to determine if your baby is healthy”.
Making predictions
Under controlled conditions, you can do anything you want. Therefore, Plense deliberately causes plants to die. “In different containers, we let tomato plants die. We explore the extremeres first, to draw conclusions and develop very precise algorithms. Of course you and I can see when a plant dies. An experienced grower can spot much earlier when a plant is deteriorating. We want to help the grower to identify this even earlier. What is the moment a plant starts to weaken? That is super important for growers: they want healthy crops. Meanwhile, we want to save energy and turn the greenhouse temperature down in winter. But turn too cold and your plant will suffer quality problems. How far can you go? That is one of the insights we want to offer”, Thijs explains.
Therefore, Plense is experimenting with Do IoT Fieldlab’s 5G installation, in the AgriFood Greenhouse at our partner fieldlab RoboHouse. The latest communication technology, 5G, enables wireless data transfer in the greenhouse. Horticulturists demand high-performance solutions and clarity on the storage of their data. “Besides testing with crops, network design is the second important part of our research. What do you store in the edge and what do you store in the cloud? We are moving towards a greenhouse that collects more and more data and where the grower has more and more insight for his decisions. You want to support the grower with knowledge about the impact of decisions and not just a sensor monitoring crop health”.
Scaling up
Measurements are now being carried out on a relatively small scale at RoboHouse. Refining this system will take a few more weeks. After that, Plense will start scaling up. “The next step is to start testing our technology in a fully working greenhouse. This is possible at Tomatoworld. We won’t let any more plants die there, because you don’t want that in a ‘real’ greenhouse. We will be trialling our system there. We want to demonstrate that we are able to know well in advance when a plant becomes stressed”. Thijs is confident about the future: ultimately, Plense wants to deliver insights that offer growers many benefits. “Less energy consumption and healthier crops. In other words, even more sustainable food production. We are eager to make a significant contribution”.
