The Unpowered Irrigation Controller for Solenoid Valves uses evaporation as a gauge to control irrigation rather than the static timer intervals in conventional devices. It works with ordinary irrigation solenoid valves of any size, one solenoid per controller, and with sprinkler or dripper systems.

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After irrigation and as water evaporates from the soil, water wicks up a polyester cloth from inside the container to outside the container and evaporates. The water in the container eventually reaches a low level corresponding to the soil drying out. The controller opens the solenoid and irrigation begins. A dripper attached to the outflow pipe slowly refills the container while the irrigation system ‘refills’ the soil. When the water in the container reaches a high level corresponding to the required watering of the soil, the controller shuts the water off and the cycle restarts.

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Once correctly calibrated, the controller only sends water when plants need it and does not overwater. It responds to the same local weather conditions as the soil. Deep or shallow watering, frequent or delayed watering – all can be accommodated. You don’t have to ‘turn it off’ over winter as rain and cooler temperatures keep the container from drying out. You can leave your irrigation system unattended for weeks on end.

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The lid of the container protects the water in the container from debris, algae, mosquitoes and thirsty animals. Any water on the lid drains into the container. 

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An irrigation system with a conventional irrigation controller can be upgraded to an unpowered system where each solenoid valve is controlled by a Unpowered Irrigation Controller for Solenoid Valves. The conventional irrigation controller and the associated wiring become redundant.