Abstract: The present invention provides an irrigation system with cheap humidity sensors and cheap automatic faucets preferably by using at the end nodes of the system low water pressure, so that much less force is needed to open and close the local waterway, and then either using simple electrical valves that do not require engines, or using for example mechanical sensors based on a bi-material of two or more materials which expand differently when they become wet, thus converting the difference of the expansion into convenient movement. Another possible variation, instead of mechanical sensors and valves, is to use for example a preferably synthetic material that tends to behave like a normal root preferably at the edge of each side channel, so that the “root” counter-balances the water supply and reaches equilibrium with it when the soil becomes wet enough, based preferably on asymmetric capillary materials.