A liquid application system comprising: a liquid reservoir 102； a body of plant growing matter 104； a supply means 108 allowing selective liquid removal from reservoir 102 for application to growing-matter 104； and connected to supply-means 108 is a power supply 116 charged by an environmental component. Liquid application occurs with respect to a condition of the power supply. Liquid application may occur depending on the charge of a battery 116 forming at least part of the power supply. Supply-means 108 may be a pump. The power supply may comprise battery charging solar panels 118 or a wind turbine. Other preferable features of the system may include: a valve in communication with a controller permitting or inhibiting flow through a reservoir tube 12； a sensor in communication with a controller to detect one or more of reservoir water level, growing-matter 104 moisture content, sunlight level； a flow rate limiter comprising a chamber with an inlet and outlet and a biased closed flow restrictor between the inlet and chamber. Also a liquid application system having a controller and liquid supply means powered by solar charged batteries, where controller and liquid-supply-means activation is determined by the degree of charge of the batteries.
