To support the global population growth, we need a massive increase in world food production. One possibility would be to grow food crops at higher densities, but this requires optimization of plant response to those high densities. Neighboring plants are able to perceive each other through touch. We discovered that the touch response in plants depend on the trichome cells located on the leaf surface. These cells initiate a calcium wave that travels from the leaf tip all the way to the petiole, and that this response provides the plants with a competitive advantage.