I think the soil sensor support is more important than a rain sensor.
I read all this discussion, checked the links and I agree that PlantLink is the most interesting project. The sensors have reasonable price. If they make the version 2 with solar power and in smaller green case, they will rock.
Edyn looks very good with their solar power, but quite pricier.
I have a 16 sensor plantlink network going and love it. Since setting up I have not killed a plant yet! I have a couple sensor outside as well that are working flawlessly to send back data. Batteries last forever too. I have not had to replace one yet and the system has been in place for we’ll over a year. Even when the company was having difficulties in the past, they had excellent customer service. This is one of the things I love about them the most.
I look forward to future integration between iro and their sensors.
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@Chudik, that would be a slick design! Perfect for outdoors use in your lawn and garden 
@keoni8888, Any feedback on the reliably of the PlantLink sensors? I assume you’re using these all indoors? Or outdoors too?
It’s great to hear they stood behind their product through good times and bad. That’s a sign they’re in it to win it!
Curious here too, I have one at home in a plant, but IMHO profile is too high for a lawn mower, so that would be a problem.
Just wonder how well they would do in the elements, outside in regards to accuracy.
SoCal Water$mart has the following list of soil moisture sensors that quality for an $80 rebate:
- Acclima ACC-SEN-TDT, Digital TDT Sensor
- Baseline BL-5315B, S-100
- Decagon ECH2O EC-5
- Irrometer Watermark
- Rain Bird SMRT-Y08
- Toro 53812, EVO-SC, P/N PSS-KIT, Pss-SEN & PSS-KIT, EVO-WS, PSS-SEN, EVO-4ID, EVO-40D
- Ugmo ProHome PH100WS
Just an FYI, I don’t have a soil moisture sensor yet and have just started investigating.
@jsbrava, thanks for sharing this list! I’ve heard of them all and have my favorites. The biggest issue I’ve seen over the years with soil sensors is proper installation, and accurate reporting of ONE sensor to manage an entire landscape. A single sensor can be used to control the irrigation for many zones (where an irrigation zone is defined by a solenoid valve) or multiple sensors can be used to irrigate individual zones. In the case of one sensor for several zones, the zone that is normally the driest, or most in need of irrigation, is selected for placement of the sensor in order to ensure adequate irrigation in all zones. Many lawns have multiple micro-climates that they need to account for; from south-facing and full sun to north-facing with a slope, a mesh network of sensors is the best approach for a true closed loop feedback of your lawn’s health.
It’s important to remember that by design, smart irrigation controllers vary based on the type of data they are using. There are generally two types of smart controllers: climatologically-based (ET) controllers and soil moisture-based (SMS) controllers.
- Climatologically based controllers are also known as evapotranspiration, or ET controllers. Generally, ET is the process of transpiration by plants combined with evaporation that occurs from plant and soil surfaces.
- Soil moisture sensor controllers, or SMS controllers, can be divided into two types; “bypass” and “on-demand”:
BYPASS: The bypass configuration is the most common for residential sites. Typically, a bypass SMS controller has a soil moisture threshold adjustment from “dry” to “wet”. This threshold can be used to lower and raise the point at which the irrigation system is allowed to water to suit specific plant, soil, and microclimate needs. This type of controller bypasses timed irrigation events if the current soil moisture content exceeds the adjustable threshold. The bypass mode of operation is very similar to that of a rain sensor
ON-DEMAND: An on-demand SMS controller initiates irrigation at a pre-programmed low soil moisture threshold and terminates irrigation at a high threshold. This type of controller is often used where a high level of customization or high level of control is needed such as commercial sites or other types of sites with many irrigation zones. Thus, this controller initiates and terminates irrigation events, whereas the bypass controller only allows irrigation events (i.e. day of the week, time of day, and run time) from a time clock. Therefore, it is critical to properly program a schedule into the time clock.
The Iro can be setup with a wired soil moisture sensor to achieve bypass scheduling.
Please keep in mind some general rules for the burial of the soil moisture sensors, which include:
- Soil in the area of burial should be representative of the entire irrigated area.
- Sensors should be buried in the root zone of the plants to be irrigated, because this is where plants will extract water. Burial in the root zone will help ensure adequate turf or landscape quality. For turfgrass, the sensor should typically be buried at about three inches deep.
- Sensors need to be in good contact with the soil after burial; there should be no air gaps surrounding the sensor. Soil should be packed firmly but not excessively around the sensor.
- If one sensor is used to control the entire irrigation system, it should be buried in the zone that requires water first, to ensure that all zones get adequate irrigation. Typically, this will be an area with full sun or the area with the most sun exposure.
- Sensors should be placed at least 5 feet from the home, property line, or an impervious surface (such as a driveway) and 3 feet from a planted bed area.
- Sensors should also be located at least 5 feet from irrigation heads and toward the center of an irrigation zone.
- Sensors should not be buried in high traffic areas to prevent excess compaction of the soil around the sensor.
Hopes this helps anyone interested in soil sensors
Best, Emil
Sources:
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Just wanted to bump this with another vote for plantlink. I’ve been using them for about a month now and couldn’t be happier. I also emailed the company before ordering and was shocked at how quickly they got back to me with all the questions I had, I hope they continue to do well.
Have you tried using it in a grass zone?
I’m not sure what you mean? I have them installed on all 9 of my zones. Is there some functionality between plantlink and rachio already i’m unaware of?
Oh cool, how are you actually using them? Does the data seem accurate?
Once they have an IFTTT integration that will be a good step into the connected sensor world.
These folks are shipping their wifi enabled controller with soil sensors - http://www.eveirrigation.com/
Any chance Rachio will create soil sensors as well? Or can the Eve ones be used? This will be a big feature, otherwise folks may jump ship 
@jjpaz This is still all vapor, as are other companies promising this all-in-one solution.
Trust me, if it makes sense from a price and utility perspective, we will be incorporating sensors. We have the platform and ability to take this type of input to modify/run schedules. This type of integration would not be too difficult.
There are a lot of factors that go into a decision of taking a relatively mid-size market (i.e. irrigation controllers), and adding a lot of complexity and cost to a problem that many people don’t feel there is a need for a solution.
If you do get an Eve, please let us know how it performs. You will also need a SmartThings hub I believe.
@franz - I was looking at the Rachio API documentation but could not find the Zone endpoint to call with new moisture data. Can you point me to the right call to update an individual zones moisture level?
Thanks!
Jay
This is not currently part of the API, but good suggestion. I will see when we can add this.
Sounds good. How else did you envision using the API to integrate moisture sensors? To affect the schedule directly? Updating the moisture level of a zone seems like the best way, right? That way the Rachio algorithm can continue to work on deciding when to water and when to skip. Thoughts?
If the sensor goes from 100% - 0%, that would work very nice!
If they provided some other abstraction (needs water, does not need water) that would also be something could integrate, maybe just using a disabled fixed schedule…which would get started automatically when watering is needed 
Adding to @franz reply, SMS (soil moisture sensors) are typically used in one of two ways pending the granularity of data and speed at which it’s reported; 1) Bypass, or 2) On-demand. For details on each, please refer to this post (above in this thread).
If you have other ideas on ways to integrate SMS, please let us know what you had in mind
I think updating the zone’s moisture level by percentage is the way to go. For example the Koubachi API returns the following:
“recent_soilmoisture_reading_value”: “44%”
@emil - I already have a rain sensor hooked up as a bypass. Moisture levels in my opinion should be On-demand and it looks like we can accomplish this with the APIs - once it is added to the Rachio API.
would we need to change the iro in order to allow those sensors ? or can we reuse the iro its available now and then plug the sensors in the future ?
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The integration would more than likely be software based, probably a third party sensor, so no need for a new Iro.