Plant enthusiasts often face the challenge of deciphering a plant's needs when leaves begin to wilt or turn yellow.

However, scientists have discovered that plants might already be communicating their distress. A new study reveals that plants emit specific sounds when under stress, signaling their needs.

Previous research indicated that plants produce vibrations when stressed, but whether these vibrations translate into sound waves has been debated. Researchers at Tel Aviv University conducted experiments in a soundproof greenhouse, studying tomato and tobacco plants. They found that plants do emit ultrasonic sounds into the air as a form of "cry for help."

According to the researchers, "We discovered that plants typically produce sounds when stressed, and each type of plant and stress corresponds to a distinct, identifiable sound. These sounds are inaudible to the human ear but may be heard by bats, mice, and insects."

The study noted that while human adults can only perceive frequencies below 16 kHz, the ultrasonic microphones used—placed approximately 10 cm from the plants—detected sounds ranging from 20 to 250 kHz. These recordings were then analyzed using specialized AI algorithms, which could distinguish between different plants and the types of sounds they emitted.

The more stress a plant experiences, the more sounds it produces.

Lilach Hadany, one of the researchers, stated, "Unstressed plants produce fewer than one sound per hour on average, while stressed plants—whether from dehydration or damage—emit tens of sounds per hour." The study also found that plants stop producing these sounds once they reach their dehydration threshold. The findings were published in Cell on Thursday.

Hadany explained, "Our study suggests the world is filled with plant sounds that convey abundant information, such as water scarcity or injury. We hypothesize that these sounds in nature are detected by nearby organisms like bats, rodents, various insects, and possibly even other plants. These organisms can perceive these high-frequency sounds and use the information."

Humans, too, could benefit from these findings. With the right tools—such as sensors that alert farmers when plants need watering—this information can be harnessed.

This capability holds particular significance for agriculture. The researchers noted in the study, "More precise irrigation can save up to 50% of water while increasing yield." As climate change leads to more frequent and severe droughts, this technology could play a critical role in ensuring food security.

Hadany concluded, "Evidently, what seems like a serene field of flowers could actually be a rather noisy place—just beyond our hearing range."