Terracotta is porous and so the water level in the pot falls as water evaporates from the outside surface of the pot. A float inside the pot floats on the water. When the water level reaches the low level, a magnet inside the float activates the valve so that the valve opens and the irrigation starts. During the irrigation event a control dripper drips water into the pot 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.
During an irrigation event, the control dripper replaces the net volume of water that has evaporated since the previous irrigation event. This volume is called the control volume. The Small Terrcotta Irrigation Controller has a control volume between 90 ml and 275 ml. The Large Terracotta Irrigation Controller has control volume between 400 ml and 2300 ml.
Key features of the Small Terracotta Irrigation Controller:
- Use for any size irrigation application with any size solenoid valve (latching or non-latching, specify when you order)
- Completely automatic
- The water in the terracotta bowl is protected from algae, mosquitoes and thirsty animals
- Smart irrigation – the irrigation is controlled by the prevailing weather conditions
- Use for both gravity feed and pressurised irrigation
- Use for both sprinkler and drip irrigation
- Use for both PC (pressure compensating) drippers and NPC (non pressure compensating) drippers.
- Use for porous hose irrigation (weeper hose or soaker hose)
- You can adjust the water usage by adjusting the control dripper
- Adjust the irrigation frequency by adjusting the float
- Adjusting the water usage does not affect the irrigation frequency, and adjusting the irrigation frequency does not affect the water usage
- The water usage and irrigation frequency are directly proportional to the net evaporation rate (evaporation minus rainfall)
- Responds appropriately when there is an unexpected heat wave
- When it rains, water enters the terracotta bowl via the terracotta saucer and delays the start of the next irrigation
- A timer is not required
- If you are using the same drippers throughout the irrigation application including the control dripper, the water usage is independent of the pressure
- You can irrigate directly from a rainwater tank without using a pump
- A light sensor provides the option of irrigating at night time only
- Uses much less water without affecting the yield
- Simple and low tech, therefore fewer things can go wrong
- Provided you have a continuous water supply, you can leave your irrigation application unattended for months on end