Issues with Watering Duration

Will the intelligence of the controller change the duration times for each zone or is it set got good once I set it? I have rotary heads with a .4” per hour output, but the default zone times for flex schedule were significantly less than the water required for Zoysia Grass, and it was turning brown. I increased the times, but will the controller change them? Also, should the watering duration time be the amount of time for the lawn to be 100% watered for the week? Hope this makes sense. Thanks!

Duration for Flex Daily schedules doesn’t usually change. What does change is the frequency that a schedule runs. So as weather gets hotter Rachio will run the schedule more frequently.

The duration in a Flex Daily scheduled is based on the amount of water needed to fill to the root depth based on the zone settings as explained below.

How do you know that the rotary heads put out 0.4" per hour - I ask because this is an especially critical setting.


Advanced Zone Settings are primarily used for Rachio’s “Flex” Scheduling. If you’re using Flex (Monthly / Daily) scheduling, the Rachio controller calculates your watering similar to that of balancing a checkbook. The plant’s soil water storage reservoir is like that of a bank vault.

However, this reservoir can only hold a limited amount of water that is useful for the crop. If you overwater the soil reservoir, it will result in water loss due to deep percolation and/or runoff losses. The turf/crop evapotranspiration (ET), or water loss & use, is the crop’s daily water withdrawal. Irrigation and effective precipitation (aka rain) are deposits to this “bank account”.

They are Hunter MP rotors, and the package says they put out .4” of water per hour.

So the 0.4" that Hunter specifies is taken from tests in a lab not the real world. Your heads could put out more or less. There are 2 ways to determine nozzle in/hour - cup test or using water meter and area of the zone. You can do a Google search on “Rachio calculating nozzle inches per hour” to learn more.

When you use a Flex schedule Rachio will calculate the duration for a zone based on it’s settings. If a zone is getting too much water or not enough water it is better to modify the zone settings rather than change the duration.

It’s best not to change the time directly. Usually setting the Advanced settings can help, and when changing them, they DO change the times. If your grass is turning brown, then increasing the Crop Coefficient will provide more water (assuming your Nozzle Inches per Hour is correct).

Usually not for a week. This time of year, it might water every 3 days, depending on the type of crop/grass, etc. If you post your zone settings we can get a better idea.