It turns out that Roald Dahl’s fantastical notion of plants “screaming” when hurt may not be as fictional as we once thought. In a study published in 2023, researchers revealed that plants do indeed produce ultrasonic popping or clicking sounds in response to stress—sounds that are outside the range of human hearing but may play a role in how plants communicate with their surroundings.

“Even in a quiet field, there are actually sounds that we don’t hear, and those sounds carry information,” said Lilach Hadany, an evolutionary biologist at Tel Aviv University in Israel. “There are animals that can hear these sounds, so there is the possibility that a lot of acoustic interaction is occurring.”

While plants are known to use visual and chemical signals to communicate distress—such as releasing powerful aromas or altering their color to signal nearby plants or attract beneficial insects—sound as a form of communication has largely gone unexplored. Hadany and her team set out to answer the question: Can plants make sounds?

Their investigation began with a set of experiments involving tomato and tobacco plants. The researchers recorded plant sounds in various conditions, including unstressed, dehydrated, and cut plants. Using a soundproofed chamber and a greenhouse environment, they captured the ultrasonic noises plants made, then trained a machine learning algorithm to differentiate between the sounds produced by the different plant states.

The results were astonishing. Unstressed plants were relatively quiet, producing little to no sound. In contrast, stressed plants, particularly those suffering from dehydration or physical damage, emitted popping or clicking sounds, detectable up to a meter (3.3 feet) away. Stressed plants produced up to 40 clicks per hour, depending on the species, with the frequency of these sounds increasing as the plants became more dehydrated and subsiding when they reached a critical state.

The study’s algorithm could differentiate between the sounds produced by cut plants, dehydrated plants, and healthy ones, and even distinguish between different plant species. The research also revealed that the ability to produce sound was not limited to tomato and tobacco plants—wheat, corn, grapevines, cacti, and henbit were also found to make similar noises.

While these findings are groundbreaking, there are still questions to be answered. For instance, the mechanism behind these sounds is not fully understood. In previous studies, it was suggested that cavitation—the formation and collapse of air bubbles in a plant’s stem—could be responsible for the popping noises. This is similar to the sound humans make when cracking their knuckles. The researchers also do not yet know if other forms of stress, such as pathogen attacks or extreme temperatures, could induce sound production in plants.

One of the most intriguing aspects of this research is the potential ecological significance of these sounds. Could other organisms be listening to these plant “distress calls”? Animals that feed on plants or even other plants could potentially respond to the sounds in ways that benefit them. For example, a moth laying eggs on a plant could use these sounds to identify a distressed plant, while herbivores might avoid plants that are signaling stress.

Hadany speculates that humans could one day use these plant sounds to better care for plants, such as detecting when a plant is thirsty before it shows visible signs of dehydration. “We could tune into the distress calls of thirsty plants and water them before it becomes an issue,” she said.

The next phase of this research will focus on understanding how other organisms, both plants and animals, may respond to these plant sounds. The team is also exploring the feasibility of detecting and interpreting these sounds in more natural environments, beyond controlled experiments.

“Now that we know that plants do emit sounds, the next question is: Who might be listening?” Hadany said. “We are investigating the responses of other organisms to these sounds, and exploring how we can identify and interpret them in the wild.”

While more research is needed to fully understand the implications of plant acoustics, this study opens up new possibilities for how plants communicate, adapt, and interact with their environment—making us rethink the silent world of plants and their ability to “speak” in ways we never imagined.

By Impact Lab