Do Plants Make Sounds When They're Stressed?

Yes — drought-stressed plants emit ultrasonic popping and clicking sounds at frequencies humans cannot hear, and scientists have recorded them traveling through open air from just four inches away.

The Experiment That Changed How We Hear Plants

In 2023, researchers at Tel Aviv University published the first peer-reviewed evidence that plants produce airborne ultrasonic sounds — meaning the sounds travel freely through air, with no microphone physically touching the plant. The study, published in the journal Cell, recorded tomato and tobacco plants under drought stress clicking and popping at frequencies between 20 and 100 kilohertz, far above the 20 kHz upper limit of human hearing.

A healthy, well-watered plant produces fewer than one of these sounds per hour. A drought-stressed tomato plant produces more than thirty — a difference of over thirty times the baseline rate. Plants under physical damage, such as a cut stem, also generate sounds, but with a distinct acoustic signature that differs from drought-stress clicks.

What Is Causing the Sounds?

The leading hypothesis is cavitation. As a plant dries out, the water columns inside its xylem — the microscopic tubes that carry water from roots to leaves — come under increasing tension. Eventually, a column snaps, and an air bubble pops into the gap with a sharp acoustic click. Think of it like a straw collapsing inward under suction. Each pop is a tiny mechanical event, but under drought stress those events multiply rapidly.

Cavitation is a well-established process in plant physiology, but whether it fully explains the recorded sounds remains an open question. The precise mechanism has not been definitively proven, and researchers acknowledge that other internal processes may also contribute.

Are the Sounds a Signal or a Side Effect?

This is the central unanswered question. The leading scientific interpretation is that the clicks are an accidental byproduct of physical damage inside the plant — not an intentional communication signal in the way animal calls are. Plants have no known auditory nervous system, and there is no confirmed evidence they evolved these sounds to warn neighbors or attract help.

But that does not mean nothing is listening. In 2025, the same Tel Aviv University lab published a follow-up finding: female moths prefer to lay their eggs on quiet plants over plants emitting stress clicks. Something in the animal world has tuned into these sounds — and that selective pressure raises the possibility, still speculative, that the sounds carry ecological consequences beyond the plant itself.

What This Means for Farming

The practical implications are significant. A machine-learning model trained on plant acoustic data can already distinguish drought-stress sounds from physical-damage sounds based on their different patterns of frequency and timing. The vision emerging from this research is a network of field sensors that detect ultrasonic plant sounds and alert farmers that a crop needs water — before a single leaf visibly wilts, before yield loss begins.

Early detection of drought stress is one of agriculture’s most valuable unsolved problems, and acoustic monitoring could offer a non-invasive, continuous solution at a fraction of the cost of traditional soil sensors spread across a large field.

The Bigger Picture

For most of human history, the silence of plants has been taken as a given. They do not move in ways we notice. They do not call out. But silence was always a limitation of human perception, not an accurate description of what plants were doing. The ultrasonic spectrum around us — in forests, in fields, in greenhouses — has been full of information this entire time. Researchers are only beginning to learn how to listen to it.