Soil temp probe

Looking for someway to monitor soil temperature for seedlings. I’d like to be able to create a situation if the temp drops to turn on a heat mat.

Any advice on a temp probe that is water/soil safe.

Thank you.

You could use a fibaro universal sensor wired with a or multiple DS18D20 temp sensors. The sensors of you use shrink tubing once you soldered the wires you could bury quite happily

Spruce - has sensors designed to monitor soil temperature and water saturation for just this kind of application. They are kind of pricey at $60 but mine seems to work totally fine, and has survived both chickens and dogs (bad animals!!) digging in my raised beds.

Best of luck!

The Spruce only monitors soil moisture I believe. The ones I have swing temp rapidly and if you open one the temp sensor is on the units board mounted above the soil. The spike is just for moisture. I’m sure someone will chime in if I’m wrong. @natec007

I think you’re right, @celblazer. I was just going off of the fact that I could get a temperature reading from it, but it looks like the box says it measures “surface temperature” and not soil temperature. I’m using it in raised beds, where the temperatures fluctuate a lot more than in-the-ground soil, so it works for my needs fine, but might not work for the OP. Sorry for any confusion there.

I’ve been using an AcuRite 00994W Digital Cooking Thermometer stuck in the soil.

That’s basically the type of device i’m looking for but i would like it to communicate back to SmarThings.

Use a waterproof DS18B20 like this

Wired into a fibaro Door Sensor for the simplest and easiest setup. Or use a Fibaro universal Sensor to wire 4 of these up which is what I use in my aquarium. These are very cheap and reliable, I bought ten on these probes for 10 pounds off amazon

P.S. No soldering is required if you use the fibaro door sensor, it has screw terminals.

How often Fibaro reports temperature to the Hub? Can it be changed?

@ivictor in essence yes you can. According to the manual

By default the wakeup interval is every 66m which is when it reports it temp. However the fibaro sensors have a better setting which saves battery which is parameter 12 which allows you to set a temperature differential which by default is 0.5deg C so if the temp changes by that much it will send the new temp reading. Messing with this setting to suit rather than the wakeup interval will be better on your battery

1 Like

At this point I do not care about the battery, I bought it to monitor the stove and I can not do it. Money wasted.
I need temperature report from it every 5 minutes to use efficiently. Do you think it can be done?
thanks (i am not good at coding, but can follow directions)

it definately can be done. I am working away from home so don’t have access to my code or the ST repository. Can someone else point out how to change the wakeup interval.

I do wonder why it has to be every 5 minutes? To me what is the reason to take a data reading every 5 minutes if the temp is the same or within half a degree. What purpose does this data point serve?

Thanks so much for responding. I am building a setup that turns switch on and off based on 2 temperature sensors difference. One is deep in the room, another is above the range. For example, range sensor gets hotter than room by X degrees (of my choice and calibration)-- switch turns on. If it is hotter less than X degrees- switch turns back off.
This is to monitor the range. If it warmer than ambient by few degrees, i get a blinking light at the door. So, nobody leaves home without checking on stove ( that already happen a few times) and blinking light or strobe will be a reminder. I know it might result in extra checking during oven cooling process, but it is ok. I need a pretty responsive temp sensors for this set up to work reliably. I plan to buy one plug in sensor that can report every minutes or by my choice of minutes (HomeSeer HSM200 ) and I need to wake up my Fibaro-probe for at least one in 5 minutes report rate, I think.
I also need a special smartapp for it. Cause now I am comparing to manual room temp, which i have to change every day loosing time and precision. Looking for help with smartapp also.
Any advice or help appreciated. Regards, Victor

You are right. It was a smartapp bug that led me to believe that I need shorter wake up interva.It was fixed.
Sensors were not quilty. Thanks

1 Like

no the spruce monitors both… see image

but it is not soil temp per se… it is the temp on the top of the sensor which sits in the sun. which would be the top of the soil…
not the temp down in the soil… don’t know if that will work for you.

Yup That’s the ambient temp but they were asking about soil temp which it does not measure.