Introduction: Table-Top Electric Plant

Plant watering can sometimes be a pain... Here's a solution that automatically waters plants depending on the moisture of the soil, no timers required!

It works like this: when there is water in the reservoir and there is no water in the soil, the pump turns on, which transfers water from the reservoir to the plant.

This design is just a scale model, but the circuit it fully functional and can be used to water larger plants!

Step 1: Materials

Here's what you will need to build the electronic part of your watering system:

  • 5v power supply (from USB charger)
  • 1 NPN transistor (S9014)
  • 1 PNP transistor (S9015)
  • 2x 100k ohm resistors
  • 1k ohm resistor
  • 47 ohm resistor
  • Stripboard or perfboard
  • Diode
  • N-Channel MOSFET (SW2N60)
  • 2 LEDs
  • Aluminum Foil
  • 4 binder clips (or paper clips)
  • 1’ of tubing for pump
  • Wire
  • Switch (optional)
  • 5v submersible water pump

Some of these parts (like the water pump) were bought from eBay, while everything else I had lying around.

I also needed two glasses and some plywood to house the plants.

Step 2: Building the Circuit

Start by soldering the components onto the perfboard (or stripboard) according to the circuit diagram above. Be sure to connect extra wiring to the motor, sensor leads, and switch (if you use one).

I then used those mounting holes to secure the board to a piece of wood, this piece of wood will later be screwed onto the base of project.

The wires that went to the motor (or pump) were soldered on as well, and some heat shrink tubing was used to protect them.

Step 3: Building and Connecting the Sensor Electrodes

I used aluminum foil for the senor electrodes because aluminum oxide (the stuff that forms when aluminum is exposed to moisture) does not flake off (unlike rust).

These 1" strips of aluminum foil were bent with an inch overhang, then they were glued into the cups using spray adhesive, about 5mm away from each other.

I also tried steel and galvanized steel for electrodes with poor(er) results.

The electrodes were connected to the circuit by attaching the wires (coming from the circuit) to the foil using binder clips.

For the reservoir electrodes, be sure to leave some space between the electrodes and the bottom of the cup. This is so the motor properly stops before all of the water is depleted.

Step 4: Transferring the Plant(s) and Connecting Tubes

At this point I transferred some grass from the garden to the plant cup. I also attached a tube to the outlet of the pump and dropped it into the (now full of water) reservoir.

To secure the other end of the tube in the soil I used a small wooden dowel which I stuck to the very bottom of the cup.

Step 5: Making a Base and Securing the Cups

I felt like a base was missing, so I cut out a 10 by 4" piece of plywood and used some double sided tape to attach the cups on.

The circuit board was also attached with some screws.

Step 6: Extras!

I set the entire system up on my window sill and recorded the average height of the grass over 7 days. It grew quite fast, and at the end of the 7 days, the water was almost gone.

I suggest adding a bit of water-soluble fertilizer to speed up growth.

So, that's how to make your own plant watering system! Feel free to modify this design to fit your needs (like watering an actual plant!).


GirlieZ made it!(author)2016-08-10

Hi! What value of diode did you use and how many?

DarshanC6 made it!(author)2016-06-19

hey what is the name of the diode ?

harman12 made it!(author)2015-04-19

R u use any soil sensor in this project

comsa42 made it!(author)2015-06-10


sami+suliman made it!(author)2015-02-05

hi, thank you so much its really great idea

could you please make diagram using fritzing program >>>>because

I don’t have much background about electronic

please I need it soon as possible

thanks man

Mohamed+Youssry made it!(author)2014-10-04

Nice but in egypt can't find water pump take 5v it,s just 220

comsa42 made it!(author)2014-10-04

Well that's why the circuit is powered with a 5v DC supply. Any USB phone or tablet charger that accepts 220v AC will work.

djstevovic made it!(author)2014-11-02

myoussry1 is talking about pump's motor, not powering electronics.

comsa42 made it!(author)2015-01-18

220 what?

mohd.habib.98 made it!(author)2014-11-29

is it okay to use 12V water pump the one used for the car glass washer ?

sunshine15819 made it!(author)2014-10-23

do i need to use the N-Channel MOSFET (SW2N60) or could I use any?

twobadrobots made it!(author)2014-09-28

Two tracks/traces of a stripboard make better moisture probes instead of foil.

tisaconundrum made it!(author)2014-09-30

but stripboard gets all green and starts to fail overtime.

twobadrobots made it!(author)2014-09-30

Oh right, yeah good point

Foxtrot70 made it!(author)2014-10-02

If the probes were made of two pins cut from a small diameter rod of Stainless Steel you would have no problem.

CandyMUFF made it!(author)2014-10-01

Great idea, well explained. It'd be great for those home grown veg! Low maintenance! Lol

MikeC5 made it!(author)2014-09-30

I have to say that this is a very interesting idea, and congrats on figuring out how to do it. Although the point of owning a plant is for decor, which is the problem here, this design doesn't look very decorative considering it has a large tube sticking out of it XD. I would be very intrigued to see a second version that was a little more discrete, Keep up the good work!

comsa42 made it!(author)2014-09-30


PhilippeG1 made it!(author)2014-09-23

use carbon rods

tisaconundrum made it!(author)2014-09-29

How about the strips of pencil lead? Burn some pencils and collect the lead from it?

comsa42 made it!(author)2014-09-29

I actually have some experience with that. Burning it isn't very efficient, but a sharp blade and two well angled cuts down the length should get the leads out :)

comsa42 made it!(author)2014-09-23

I absolutely will next time

HBSkirmit made it!(author)2014-09-28

On your schematic, you have the collector and emitter leads reversed on the S9014 transistor.

comsa42 made it!(author)2014-09-28

Yup, I partially fixed that on the video and image, but the letters are still bad.

stills made it!(author)2014-09-28

some time ago, I've built a similar project and I've noticed that applying constant current to the soil, polarizes it, increasing the resistance. The result was overwatered soil. How is yours working?

comsa42 made it!(author)2014-09-28

Mine works great. I'm not quite sure by what you mean when you said "polarizes the soil"

roberto_mansoni made it!(author)2014-09-28

Is the NPN transistor upside down? I can't see a condition where the transistor would conduct.

gravityisweak made it!(author)2014-09-24

Thanks for not using an arduino for this. Not that I dislike arduino but people seem to be forgetting that you can obtain similar results for simple projects without needing such overkill.

comsa42 made it!(author)2014-09-27

That's absolutly right. I mean, you can get Arduinos for 7$ shipped nowadays, but that's still overkill.

tomatoskins made it!(author)2014-09-22

This is really cool. I'm always forgetting to water my plants and this would solve that problem. I'd just need to remember to fill up the water supply...

gravityisweak made it!(author)2014-09-24

You could probably set that pair of moisture sensors in the water supply, to beep when your reservoir is empty and their connection is broken.

saymowan made it!(author)2014-09-23

Awesome project! Thanks for sharing

MsSweetSatisfaction made it!(author)2014-09-23

This is so cool, now maybe my plants will be able to survive. Thanks for sharing!

Jan_Henrik made it!(author)2014-09-23

That is very awesome, I realy need to build it, my last plant died too fast ;-;

About This Instructable




Bio: I'm a highschooler who is interested in technology, science, and engineering. In my spare time I work on projects that allow me to learn ... More »
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