Researchers create a wearable sensor for plants

16-05-2022 | By Robin Mitchell

Recently, researchers have developed a wearable sensor for plants that can detect signs of thirst before any visible signs show. What challenges does plant care present, what did the researchers do, and how could such sensors help farming of the future?

What challenges does plant care present?

Those who do not have a green thumb will undoubtedly have killed a house plant at least once, whether due to overwatering, underwatering, lack of nutrition, or root overgrowth. Of course, some plants are much easier to care for than others, with ferns being particularly easy to manage while orchids are notoriously hard to maintain.

One factor that makes taking care of plants particularly challenging, even for those with a green thumb, is figuring out the state of a plant. Unlike animals that show clear behavioural changes, plants don’t make noises, and they don’t show immediate signs of distress. When changes in their appearance start to show (such as wilting or browning), it can often be too late to act, especially if the cause of the condition is a disease.

Even in the case of having a lack of water, it isn’t always entirely apparent before it is too late. Simply adding extra water to the soil that the plant is potted in can also have negative consequences on the plant by washing nutrients away and drowning the root system (roots require air and water). Tests can be done on plants, but these are often intensive and intrusive, requiring parts of the plant to be damaged.

But it’s not just house plants that face this challenge; even farmers face these challenges. Do they need to add nutrition? Do crops require watering? How much water should they be given? These questions must be answered carefully; otherwise, entire crops can be lost.

Researchers develop a sensor that can detect thirst levels of plants

Recognising the challenges faced with plant health, researchers have recently developed a new sensor that can be attached to a plant’s leaf and determine the thirst level before it shows any visible signs of distress. Creating a sensor that could be attached to a plant presented challenges as current sensor technologies would separate from the plant, thus providing inaccurate data.

To solve the challenge, researchers created an electrode using nickel with a meandering pattern attached to a piece of adhesive material. Additionally, another sensor was developed using burnt paper on a waxy film to compare the performance of the two. After extensive testing, the nickel-based sensor proved to be more reliable as the burnt paper version of the sensor would fall off during windy conditions.

Finally, the sensor was then attached to external circuitry and then read wirelessly by a smartphone app. From there, the moisture content of the leaf could be seen, and the data provided by the sensor showed dehydration before any visible signs could be seen.

How could such sensors help farming of the future?

Being able to directly monitor the health of a plant without the need for invasive measures could provide massive benefits to farmers. The use of remote sensors allows for large amounts of data to be gathered. Collecting this data alongside other environmental factors can help researchers create accurate AI models on plant health and corrective actions. This, in turn, would also help to limit the amount of water needed and may even be able to reduce the overall amount of fertiliser used.

The use of such sensors also allows farmers to use sensors on plants without damaging them, which could be particularly important for valuable produce that grows on trees and other long-lived plants. The sensor currently demonstrated by the researchers is still in its infancy, but with more development, it could be used to transform the agricultural industry.


By Robin Mitchell

Robin Mitchell is an electronic engineer who has been involved in electronics since the age of 13. After completing a BEng at the University of Warwick, Robin moved into the field of online content creation, developing articles, news pieces, and projects aimed at professionals and makers alike. Currently, Robin runs a small electronics business, MitchElectronics, which produces educational kits and resources.