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 tomatos, 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!

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.

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.

@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)?

I’d also like to know more about your potted plant problem. To clarify: these are outdoor potted plants, and you’d like to irrigate them year-round, but can’t use the in-ground sprinkler system because it gets winterized. We are considering the utility of soil sensors for potted plants like this. The only caveat would be risk of freeze damage to any in-situ irrigation system (i.e. off a hose bib). Do you imagine a sensor in a pot driving an in-situ system, or would you just be using the sensor as direct feedback for when to water manually?

Really appreciate your input, cheers.

@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 ya’ll can come up with an economic way to monitor soil moisture and help improve your product.


While I would love to have an automated system based on moisture sensors, I don’t think it is practical. Someone posted here a while ago that they got actual soil moisture charts (for a golf course or other commercial system), and had also used the service on his yard. But for most everyone, that kind of system is out of the question. I believe even getting the information was on the order of thousands of dollars per year.

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.

Even if every zone had a 100% accurate moisture meter in it, is the meter in the right or best location? And I personally believe that people don’t know their actual Nozzle Flow within 30-50% or more. Without knowing all of that, we’d still be stuck adjusting /something/ to provide more or less water for the lawn as needed.

Anyhow, yes, I’d love to see something, but don’t think it will happen, and we’ll still have to adjust things to get them right. The moisture graph in Flex Daily may not be 100% accurate, but it describes on a per zone basis how the zone is doing, on average, or at least how Rachio thinks it is doing. I personally think that’s enough, on a properly calibrated and adjustable system.

@gaustin Thanks for your input. I agree with your general principle that this kind of engineering comes down to moisture management.

When you monitor drydown, do you typically see a similar drydown curve (i.e. a similar elapsed time to some defined level of dryness) after your irrigation events when you measure various parts of your yard?

I’m curious because a potential blocker to this project could be that soil texture/composition variations in real life yards vary across such a large range that finding a characteristic drydown pattern would prove impractical. Like any modeling application we do, success with a sensor would require that we could generalize some expected drydown behavior to most people’s turf and garden zones (i.e. not move into a world with a ton of edge cases). Cheers.

@rraisley Your points about inevitable variability in most yards is well taken, and is likely the largest blocker to coming up with an easy to use, consumer solution. We are going to push the hardware and software to see what’s possible.

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. So the idea for a sensor providing dry-down feedback is to basically get around the nozzle rate problem.

After observing our system working on a few hundred thousand yards for a few years, the applicability of a sensor arises from considering what you point out: a properly calibrated and adjustable system. You are clearly technical, detail-oriented, and patient enough to have calibrated your system well, but a large segment of customers lack the time, interest, or know-how to do this; thus we have a lot of poorly calibrated systems out there that could be optimized. Certainly some confusing elements of our UI are not helping (improvements coming!), and we’re also exploring a sensor that provides site-specific info on drydown rates as well. Appreciate the conversation!

1 Like

@drew_thayer, this dry down is highly variable and mostly dependent on the weather and ET. I was using it to match what the Rachio was doing so I could hone in my yard to your model. I still have to skip cycles and add syringe times here and there but I’ve been happy with my Rachio.

I live just north of Houston, so when the weather is hot and dry in the summer with no afternoon showers I can be very precise with my watering.

@rraisley, I’m the one you are referring to with the Visual Insight. I do believe that there can be a smaller scale application to this technology but it will definitely need to be economical for home use.

At least you are looking into the possibilities.

1 Like

Did even know they existed. New to the whole smart controller stuff… I can see these useful if it tells you the type of soil and what nutrients you need for it. Kind of like a soul tester in realtime. Maybe integrate that with knowing soil moisture? That’s something I would buy.

A soil sample test is the only way you’ll get that. But you only need to know it once a year or so for most nutrients, while Nitrogen has a pretty fixed application rate, depending on grass type and climate.