Potassium is an essential nutrient for all living things. Plants need it in large quantities, especially for growth and in order to withstand stress better. For this reason, they absorb large quantities of potassium from the soil. In agriculture, this leads to a lack of available potassium in the soil—which is why the mineral is an important component in fertilizers. A team of German and Chinese researchers has now shown, for the first time, where and how plants detect potassium deficiency in their roots, and which signaling pathways coordinate the adaptation of root growth and potassium absorption to to uphold the plants potassium supply.