[Updated] Yet Another Automated Plant Watering Project


I have been working on an automated plant water system and have published detailed instructions on Hackster.io.

You can read all about it there but, I decided to build my own in order to get more experience with the Particle Platform - and I have learned a fair bit in the process thanks in large part to this community and @ScruffR, @RWB, @Viscacha, @LukeUSMC, @mariahernandez, @jotathebest, @mikemoy and @peekay123 in particular.

The system uses the Photon, Ubidots and the Weather Underground as well as some creative plumbing to deliver the following:

  • Remote monitoring via web or smartphone
  • Notifications via e-mail or text if anything goes wrong
  • Intelligent watering based on soil moisture and weather forecast
  • Fail-safe design which would not lock up and would fail safe (and dry)
  • Ability to extend and improve the system with data over time
  • Tap into the house’s plumbing for all-season use

Please take a look and let me know how I can make it better. Whether I continue to develop this project will depend on how much interest and support I get. I know there are a large number of similar projects out there.




Thank you for sharing this!

That’s an awesome project, and thanks so much for putting that guide together. I’m super interested in the project, and predictably unable to offer any support if you were to carry it forward in the near future. But thought I’d chime in that that setup is super cool!


Thanks for taking a look and I am glad you liked it. I am thinking this is something that I will continue to develop as I have found it very comforting know my plants will be OK while I am away. I am still working on the fine tuning and I may need to either dial up or back the watering but, based on this chart, I have been able to maintain the soil moisture of the plants over the past week even as the temperature and rain have varied.

(Note: The green spikes are watering events. The blue line is the arbitrary soil moisture measurement based on capacitance. Watering on August 4th was not recorded by Ubidots as the Webhook timed out since I am using Ubidot’s free service.)

As for support, comments like yours are all the encouragement I need.



I’m also considering doing this for my wife’s house plants that she forgets to water sometimes.

I have seen the cheap PCB gold plated soil moisture sensors that corrode quickly over time and the fact that you’re using something different that I think does not corrode seemed ideal to me. How did you come across capacitive moisture sensing?

What exactly did you spray on the sensor to protect it? Something plant save I assume?

Where do you think is the best place to get the capacitive moisture sensors based on your research? I’ll pick some up and then copy your project but do it on the Losant platform just to give people another option, their free account provides 1,000,000 send, receive events for free which should be plenty for any project.

Overall I see this type of monitoring very beneficial for farmers to help increase their yields but the soil sensors need to last years to work properly in that enviroment.

@RWB, the source of the capacitive moisture sensor is on the Hackster.io posting. You can find them here:

The pcb design files and firmware are here it seems:


@peekay123, Thanks for responding, in Japan so off by 13 hours this week.

@RWB, It would be great to have you implement this project, I am sure you could make some great suggestions for improvement and I would like to see what the Losant Platform brings.

I used Plasticote to spray the probe as it is waterproof but it can also be peeled off if you make a mistake (and I make a lot of mistakes). I may look for something better next season but it is working very well for now and does not impact the sensitivity of the problem much at all. This is the advantage of the capacitive soil sensor - no metal contacting the soil.

As for plant safe - um not sure there. Once it dries, I can’t imagine there being much interaction with the soil.

I will likely lay out a PCB for this in the next week or so. I will get three from OSHPark and would be happy to send you one for free. Would love to get more input for improvements.

Also, I plan to do some more Webhook work on this one - need to move away from the JSON approach and start using BODY from the command line as sending the “context” such as “NOT NEEDED” when each watering value is assigned is beyond what a JSON web hook can handle. Not sure if the Losant platform can solve this as it seems to be a Particle Webhook limitation.




Updated with new OshPark board and better outdoor electrical protections.

You can see the full project writeup here. Though I still need to take a stab at rewriting my code using finite state machines as has been suggested above. I also plan on adding a flow sensor primarily for leak detection.

Here is a snapshot of the watering events (green) and soil moisture over the past couple weeks. This system has kept my garden alive despite my travel schedule.




I like how small the board is.

It’s nice to put this stuff to a practical use that actually makes a difference in your life or surroundings.

The Chirp soil moisture sensor that I got for my wife actually started chirping the other day indicating it was time for watering which was neat. Normally she would either under or over water it but now the plant soil should stay reasonably hydrated.