Moisture Balance at zero

I have a new yard (sod). I have been trying to get the flex schedule to water the yard. I have determined that flex schedule will only water one time a day. I was hoping that it would water when moisture level reached zero. Okay, I accept one time a day. (As an aside, there needs to be an option for new grass, when it waters every x hours to keep everything wet).

So, I have adjusted the following so that the length of watering will be longer:
– available water 0.2 in
– root depth 0.5 in
– allowed depletion 90%
– efficiency 80%

Still not enough water, so I have adjusted to the highest level of more water.

Still, the moisture level shows 0%. So, I have been manually watering. Still the moisture level is at 0% for five days. I look at the moisture level detail and it shows
– previous moisture balance = 0 in.
– flex schedule = 0.08 in
– manual = 0.10 in
– Evapotranspiration = 0.27 in

So, Iro knows that the lawn is not getting enough water, but is not increasing the amount of water or frequency (more than once a day).

What am I missing?


I discussed this with others at work. In the discussion, it was determined that since I thought the Iro would run more than once a day, the 0.5 in root depth made sense. However, since the Iro will not run more than once, then I needed to extend the root depth to 1.0 in. I did that and the run time is twice as long. I will let this run for a couple of days to see if they irrigation exceeds the ET.


@torpster, thanks for reaching out. We do not recommend using Flex Schedules on new lawns (sod or seed) – sorry for any confusion. A Fixed schedule using IFTTT to automate hourly schedule runs would be your best solution. Here’s another community post that details how to setup the IFTTT with your Iro.

I’d highly recommend reverting to the default settings for root zone depth and allowed depletion. 0.5 inches (even 1 inch) is a VERY swallow root zone depth. Also, setting your allowed depletion to 90% is the opposite of what you want to do for sensitive, shallow rooted plants. Depending on your plant types, Allowed Depletion should look like this:

  • For most landscape purposes, 50% AD represents a reasonable overall value for the typical soils and plants used in landscapes in which you irrigate when the soil moisture level is half depleted.
  • For sensitive, shallow rooted plants (where little reserve water is available), or very heavy compacted soils, a smaller depletion should be considered (i.e. 30-50%)
  • For stress-tolerant plants, such as desert plants, deep root zones, or lighter soils, a larger depletion can be used (i.e. 50-70%)

Hope this helps :slight_smile: