'Plant patches' could help save gardens and farms from environmental stressors. Image: Popular Science compositeShareAnyone who has tried to keep porch plants or a home garden alive through seasonal changes knows its a task easier said than done. Abrupt temperature changeslike cold snapsand prolonged periods of drought can stress plants, disrupting their normal biochemistry. If not addressed quickly enough, those stresses can eventually kill the plant. Disappointed growers often only see the tell-tale signs (like shriveling or browning leaves) after its too late. But a new plant-wearable device developed by researchers at the American Chemical Society could offer an early warning system.The wearable, detailed this week in the journal ACS Sensors, comes in the form of an electromagnetic sensor attached directly to plant leaves. Its purpose is to detect hydrogen peroxide, a chemical plants release when exposed to environmental stress. The sensor consists of an array of microscopic plastic needles mounted on a flexible base. That base is coated with a chitosan-based hydrogel capable of detecting small amounts of hydrogen peroxide, which is then converted into an electric current. The presence of that current alerts growers to their plants stress levels.This sensor measures hydrogen peroxide, a marker of stress in soybean and tobacco plant leaves.Credit: Adapted from ACS Sensors 2025, DOI: 10.1021/acssensors.4c02645 In several experiments, the wearable accurately identified the presence of hydrogen peroxide in groups of plants exposed to a pathogen. In theory, the research notes that a similar type of wearable could be applied to larger crop yields as an affordable way to detect stressed out plants before they are beyond saving.This sensor technology has the potential to function as a portable device for on-site measurement of reactive oxygen species in plants, providing a rapid and cost-effective solution for hydrogen peroxide quantification, the researchers write in the paper.Identifying stressed out plantsA number of environmental factorslike drought, high salinity, and pests or pathogenscan induce stress in plants. When that happens, plants naturally produce hydrogen peroxide, which researchers say serves as an indicator of acute stress. This signals plant cells to activate a variety of defense mechanisms. If the stressors persist for too long, they can ultimately kill the plant. In the past, researchers monitored early signs of plant stress by taking small samples or observing changes in fluorescence. But neither of those options are perfect. Taking samples can damage a plant and induce stress of its own and looking for fluorescence changes can be difficult to clearly detect.Thats where the plant wearable comes in. By attaching an electrochemical sensor directly to a plants leaves, the researchers believed they could get a near-instant response while keeping physical disruption to the plant at a minimum. In practice, the sensors microneedles would penetrate the plant tissue and detect hydrogen peroxide without the need to gather leaf sap extractions. The microneedle surface is coated with a thin layer of gold, mixed with a bio-hydrogel composed of biocompatible and hydrophilic chitosan and horseradish peroxidase enzymes.This reusable patch (shown on the underside of a tobacco leaf) could help growers make decisions earlier to maintain the health of their crops through earlier detection of plant stress.Credit: Adapted from ACS Sensors 2025, DOI: 10.1021/acssensors.4c02645 Researchers attached these sensors to several groups of tobacco and soybean plants. Some of those plants were exposed to a bacterial pathogen called Pseudomonas syringae pv. tomato DC3000 while the controls remained healthy. As expected, the sensors attached to the infected plants quickly showed signs of hydrogen peroxide, indicating stress. Researchers say the electrical current levels measured by the sensors were also directly related to the amount of hydrogen peroxide exuded. The same patches could be reused up to nine more times before the needles wore out and lost their shape.We can achieve direct measurements in under a minute for less than a dollar per test, researcher and paper coauthor Liang Dong said in a statement. This breakthrough will significantly streamline analysis, making it practical for farmers to use our patch sensor for real-time disease crop monitoring.Dong and his coauthors are optimistic that this technology could potentially be scaled up to help farmers and gardeners remotely monitor their plants for signs of health disruption. Its part of a larger, emerging trend in the agriculture industry to incorporate AI-enabled monitoring sensors and even autonomous robots to provide round-the-clock care for plants. And the stakes are high. Every year, the National Institute of Food and Agriculture estimates that around 2030 percent of global crop production is lost to pests and disease, translating to estimated losses surpassing $220 billion.