The Unpowered Wicking Irrigation Controller is suitable for automatic sprinkler irrigation or drip irrigation. The valve operates with water supply pressure as low as 1 metre head. The interval between irrigation events is automatically controlled by the on-site prevailing weather conditions (namely, evaporation and rainfall).
 
A polyester cloth wicks water from inside the plastic container to the ourside to evaporate. When the water level reaches the low level, a magnet inside a float activates the valve so that the valve opens and the irrigation starts. During the irrigation event a control dripper drips water into the polyethylene container via holes in the lid and the water level rises. When the water level reaches the high level, the magnet inside the float disengages from the valve so that the valve closes and the irrigation stops.
 
Position the Plastic Unpowered Irrigation Controller in a suitable location in your garden so that the evaporation matches the evaporation at your plants.
 
During an irrigation event, the control dripper replaces the water that has evaporated since the previous irrigation event. This volume is called the control volume. The control volume can be set to any value between 600 ml and 1260 ml. 
 
Key features
Unpowered (no batteries, no solar panels, no electronics, no computers)
Water supply pressure 10 kPa to 800 kPa
Use for sprinkler irrigation or drip irrigation
Use for gravity feed or pressurised irrigation
Use indoors or outdoors
Can deliver water to at least 400 2 L/H drippers
If the control dripper is an irrigation dripper, then the dripper discharge will be the control volume for each dripper 
If the control dripper is the adjustable control dripper provided, then adjusting the control dripper adjusts the emitter discharge (dripper or sprinkler)
Adjust the interval between irrigation events by adjusting the area of exposed fabric
Responds automatically to on-site evaporation and rainfall
The irrigation frequency increases significantly during a heat wave
Irrigate directly from a rainwater tank without using a pump
The lid on the plastic pot protects the water from debris, algae, mosquitoes and thirsty animals
Simple, unpowered, and low tech, and therefore fewer things can go wrong
Leave your irrigation application unattended for months on end