How do you interact with soil sensors?

Hi Rachio users,

The product team is exploring the concept of integrating a soil moisture sensor into our ecosystem. No promises, we are merely in the research phase right now, but we’re quite interested in the potential. To determine if we should pursue this, we would love to get your input:

• Have you purchased a soil sensor to augment your irrigation? How do you use it?
• Does anyone track soil moisture on their own? How does this data help you make irrigation decisions?
• If you had one soil moisture sensor that you could move around your yard, and it provided useful input to your zone watering, what zones would you put it in? Why?
• For what specific use cases would you want to measure a zone with a moisture sensor (e.g. overseeding, new turf, growing tomatoes, potted plants…)

We know there are some issues with the soil moisture graph, and have parallel projects to address those. We’d really like to hear how you all use soil sensors, or how you would want to use them with our system. Thanks!

post by drew_thayer on Oct 11, 2021

I don’t use them, but wish I could because I have some particularly troublesome parts of my yard that I cannot adjust properly due to ground water. I’ve considered buying some, collecting the data, and looking at any interface for controlling the Rachio programmatically so I could basically bypass the intelligence of the controller for some zones.

Another project is moisture readings and automatic watering for certain potted plants that need it year-round. The hard part there is that the sprinkler system needs to be winterized every fall, so I don’t have a way to get water there year-round without some plumbing work.

post by eric_j on Oct 12, 2021

Not all soil sensors send the same information to the controller. They either tell the system to turn off when there is saturation or tell it to turn on when it’s dry.

post by drew_thayer on Oct 13, 2021

@eric_j I’m curious about your situation. Do you have groundwater commonly saturating parts of your yard, so much so that Rachio’s weather and et-based system is watering too frequently? And you would ideally use a moisture sensor to prevent those extra waterings (i.e. wait until the soil is actually dry enough to need watering)?

post by gaustin on Oct 13, 2021

@drew_thayer, obviously I’m biased here but you can’t truly have a smart controller without knowing the moisture content of the soil. All environmental stresses ultimately come down to moisture management. If you over water you create an environment conducive to disease and if you under water you run the risk of wilt, creating a weakened condition for insects to thrive.

• Ideally you would be able to have a mobile system as different areas have different soil, sun exposure, slope, etc. (with the size of most home lawns you can probably get a way with fixed sensor)
• I mostly use my meter to monitor my turfgrass
• I monitor my dry down after an irrigation cycle and also my distribution uniformity.

Hopefully y’all can come up with an economic way to monitor soil moisture and help improve your product.

post by rraisley on Oct 13, 2021

What I did see in those charts, though, is what I observe in my own yard: moisture varies greatly, even in smaller areas. I have a $100 moisture meter, and get different readings several feet apart in the same zone. Yet the grass looks consistent and proper. Water can bleed from one area to another, so it /wants/ to even out, but does it poorly.

In my tests using catch cups, I found that the water applied over any zone can vary greatly (3:1 or more), and yet the yard, again, looks fine and even. The soil compensates. Some. So even if we could measure actual moisture, accurately, across a zone, the water being added is nowhere as even as we think, and would like, it to be.

post by drew_thayer on Oct 14, 2021

I appreciate your anecdotes about the range of application you’ve found in your yard. This is common; I’ve found similar variation while testing on mine.

Nozzle flow is, as you’ve identified, the hardest important parameter in our system to estimate, or even measure accurately. We’ve been living in a world where we just have to assume that this rate is pretty erroneous for most customers, and I’d love to constrain that any way we can. The idea for a sensor providing dry-down feedback is to basically get around the nozzle rate problem.

post by gaustin on May 30, 2022

I’ve tried moisture sensors and I’ve found that since it requires a mechanical connection to the soil, that it’s highly hit-and-miss if you get a satisfactory connection and even less likely that it will remain good for a period of months or years to be relied upon. A better design is needed for anything beyond manual spot-checks.