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Using ESP to keep plant alive.


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My daughter bought me a plant last christmas and as I've never managed to keep a plant alive for more than a few, weeks I decided an electronic solution was the answer.

After a few different iterations my current version consist of an ESP8266 NodeMCU board, a HX711 electronic scale and a DHT22 temperature and humidity sensor. I did have it auto watering until about 6 weeks ago when a bug caused a problem - hopefully found said bug and squashed it and will resume auto watering soon.

The ESP acts as a HTTP server and an FTP server. The page it serves up gives a very interesting chart to look at.
Here, blue trace and scale are weight in grams, green is humidity and red is temperature. Each peak of the red line is a day.
The thing I find most interesting is the humidity. For the last few days I've been getting static shocks more than usual and didn't know why. Looking at the chart it was rather obvious.

This has been an interesting project and I've learnt a lot - especially html, javascript and how server/client communication works.

The code on the ESP only uses about 300k of (4MEG of) flash, 35k of ram and the file system (SPIFFS) has less than 100k used.

Anyway, just wanted to demonstrate how powerful the ESP chips are. I can get the Wemos mini boards with 80k ram and 4meg flash for less than US$5.



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Hi Pommie,

Probably like many folk, we already use those sensors with the Arduino and also have a little used ESP board, but again some of us do not have the knowledge/skill to master the ESP to PC side of things.

Would you be interested in sharing / posting your project in full, so we can hopefully learn from your good work ?

Nigel Goodwin

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A couple of questions Pommie, what are you using to generate your graphs?, how often are you taking your readings, and are you using battery power or mains?.

I usually update every ten minutes, which seems fine for temperature/humidity, and battery power seems fine for that (putting the ESP in deep sleep between readings). I've got a mix of DHT22's and BME280's, the BME280's seem a lot better - I find the DHT22's seem rather vague about humidity, and tend to give wildly different humidity readings.

But with either, it's important to space the sensor from the ESP, or the heat from the ESP affects the sensor.


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I'm generating the graphs with javascript. I didn't want to rely on any outside code that might "move" so wrote my own. The html page requests the readings (weight, temp, humidity) every 2 seconds but the logged data is every 5 mins. The vertical lines represent a 6 hour period.

When I get time I'll simplify the code so it's easier to follow and post it here. ATM, it consists of a few html pages a huge data file and lots of ESP code.



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What I pictured from the title of this thread was you using ExtraSensory Perception to communicate with the plant and keep it motivated to live.


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That's really cool I been playing around with some nano 33 IOT Wish I was good at writing code for pc side too.
I using the Arduino cloud


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There is no code on the PC side. It just opens the page in a browser.



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plant care for dummies:
1) pay attention to the body language of the plant - drop in leaves means need water.
2) Plant water needs to set for 24 hours before using to remove chlorine
3) A small amout of liquid plant food can be placed in the water at least oce a month.
4) check soil with finger to assess need for water.
5) use room temperature water.
6) try not to water at night.
7) Cut the discolored leaves into a leaf shape, removing the discolored portion.
8) remove the really "Dead" stuff
9) Assess the plants lighting needs (plant datasheet)
10) You also don't want extreme changes in environment caused by moving the plant.
11) Probably the Pointsetta is a really difficult plant to take care of. I don't do them. They generally stay alive, but don;t bloom.
12) never did orchids either.


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A lot of plants prefer to dry out completely before they get a soaking , also stressed plants ( pot bound / dry-wet cycle ) tend to flower more. Others like cool roots, so don't use black pots on a sunny window sill . ventilation is also important ..
My 2c worth..

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