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Automatic Watering System for Plants using Arduino

After watching this video you will be able to:

Lets make an automatic watering system. This project is an extension of our prior experiment, where you learned how to connect moisture sensor to Arduino. This time we are also going to connect a relay and water motor to the Arduino. We will then write a program to take input from soil moisture sensor and switch on or switch off the water motor based on the data received from soil moisture sensor.

What is Automatic Watering System for plants?

The automatic watering system helps you to water plants at your home, garden or farm in your absence. It uses technology to detect the moisture level of the soil and automatically water the plant when there is no moisture detected in the soil.

Can I make one myself?

Yes, this is what learn by watch do, helps you to learn to do things yourself. We have created a video and this post to show you the procedure to make it on your own. If you will follow both carefully you will be able to make it yourself. If you face any problem as in the comment. You can also ask us for the paid services.

How long does it take to make an automatic watering system myself?

It depends on your prior knowledge and experience with Arduino. If you are new to that and follow the video and instructions given in this post, you should be able to make it within a day. But if you are planning to showcase in some science exhibition, We recommend you to start at least one week prior to the deadline.

What are the required components?

The required components are given below. We have also provided links to buy the components from Amazon and Flipkart so you do not have to waste your time in search for the right component.

  1. Arduino Uno R3: http://amzn.to/2srIMT3 | https://goo.gl/MkGoQC
  2. Soil moisture sensor: http://amzn.to/2sQLiCJ | https://goo.gl/B9ewV6
  3. Buzzer: http://amzn.to/2sXK2sz
  4. 4 Channel Relay for Arduino: http://amzn.to/2s09f8s | https://goo.gl/Dtd7Xb
  5. Jumper wires: http://amzn.to/2s9wfkc | https://goo.gl/QK5BN4

Source code

int ACWATERPUMP = 13; //You can remove this line, it has no use in the program.
int sensor = 8; //You can remove this line, it has no use in the program.
int val; //This variable stores the value received from Soil moisture sensor.
void setup() {
  pinMode(13,OUTPUT); //Set pin 13 as OUTPUT pin, to send signal to relay
  pinMode(8,INPUT); //Set pin 8 as input pin, to receive data from Soil moisture sensor.
void loop() { 
  val = digitalRead(8);  //Read data from soil moisture sensor  
  if(val == LOW) 
  digitalWrite(13,LOW); //if soil moisture sensor provides LOW value send LOW value to relay
  digitalWrite(13,HIGH); //if soil moisture sensor provides HIGH value send HIGH value to relay
  delay(400); //Wait for few second and then continue the loop.

Frequently Asked Questions

What is your goal?

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95 thoughts on “Automatic Watering System for Plants using Arduino”

  1. plz help me!! When I am Uploading the program there is an error.the error states that “expected initializer before ‘WATER’. PLZZZ HELP ME

  2. Hii sir actually we are doing a project similar to your’s. That we can water a plant at regular intervals of time including detection of moisture. briefly, if you have a habit of watering plants daily at 5 pm even in your absence the motor should on automatically and water the plants. The amount of water should be watered to the plants are based upon the moisture content in the soil. Please help us sir as early as possible.

  3. sir actually we are doing an project similar to this but we want to know how to change the angle of the water pipe if we have 2 or more plants so that it can water the plant which has less moisture.

  4. sir, i followed your steps and connected all components and wrote program too..but it works opposite to what you have showed when i place soil moisture sensor in wet soil the motor is on and when i remove nothing happens plz help ..

  5. finally i solved my problem sir i just changed this values
    digitalWrite(13,HIGH); //if soil moisture sensor provides LOW value send LOW value to relay
    digitalWrite(13,LOW); //if soil moisture sensor provides HIGH value send HIGH value to relay
    compare this with original program
    this is working for me
    when i remove the sensor from the wet soil the motor is on state and off when i place it in wet soil
    anyway thx for program

  6. If i want to make more than plant which components should add? A higher motor?plz reply i’m working for school project.

  7. Sir,can we add more than two plant for watring system using one motor..plz give me a code for that..plz help us

  8. Instead of ac motor we use dc motor
    Is it working in automatic watering system for plants.
    When we don’t put soil sensor inside the soil water flow from pump but we put sensor inside the soil it will not work water is flowing continue instead of stoping
    Plz help me what can i do.

  9. In a same area it will dry in some part and wet in some part.In such condition s how can use make of this sensor

  10. Great project. really enjoyed it. Could you do a project where you control this type of thing via wifi or app?

  11. Hi, I am receiving the reverse for the output…..when the soil moisture sensor is placed on dry soil then water is not flowing while water is flowing when the soil moisture sensor is placed in wet soil…How to overcome this?

  12. Hi, please help me. When I compile the program at the beginning there is no error but when I want to upload it to the board it says that it can not as if it did not detect it.
    Then, I got a 3-6 v motor and I connected it to a cell phone charger like in the tutorial but I checked all the connections and it does not work. I hope you can answer fast

  13. Hello
    I am trying to write a code for two soil sensors using python. i got it work for one sensors , but i could not do it for two sensors, so my question is there a specific loop for two sensors ??BTW, I am using Raspberry pi

  14. GPIO.setup(16, GPIO.IN)
    GPIO. setup(18, GPIO.OUT)

    GPIO.setup(7, GPIO.IN)
    GPIO.setup(7, GPIO.IN)

    while True:
    if GPIO.input(16)==1
    GPIO.ouput(18, True)

    if GPIO.input(7)==1
    GPIO.ouput(15, True)

    GPIO.setup(18, GPIO.OUT)

    GPIO.setup(15, GPIO.OUT)

  15. I have coded the arduino and done all the connections as shown in the video but the pump isn’t coming on.can I get some help on making it work

  16. Hi, I am a complete beginner. How to use this device for multiple plants at once? I mean if I use 2 motors and soil sensors, how to make it work for both?

  17. Hi
    I am Pratham
    The coding you gave in the videos not working can I ask for the correct coding I used 1 channel relay board instead of 4 channel relay board and other things are same
    Thank you

  18. The things working reversly ..like the water is being pumped when there is moisture and not being pumped when no moisture..please help me regarding this…

  19. Good stuff ! I’m willing to do this project but I have small query. What if water from source get empty ? Because if there is no water to suck, the motor can fail or damage. How to overcome this small issue?

  20. Hi i am doing the project of automatic watering plants using arduino.
    I have done the connections according to the video given.
    I am sorry i did not understand the above codings posted in the above comments as i just have the very basic info. about coding done at school (c++).

    The problem is that when i give the power supply to both the arduino and the dc water pump, the pump starts working and also the sensor is dry. But now is the problem….

    The pump is running but according to the project the pump should stop when the sensor is dipped in water/wet soil. But that does not happen.

    When i take it out it stops. Again when i dip it in water and take it out it starts. This happens only a few times and then stops and nothing works.


    The pins for the coding is given below…
    The DO from the sensor – pin 9
    Pin 12 from arduino – IN1 of relay.

    Again please send me the correct coding and advice me if there is any problem.

    1. Hi, there was a problem in first line. Replace AC WATER PUMP with ACWATERPUMP and the program should work. Infact you can remove first two lines of the program and it should work perfectly.

    1. hello sir i have done a demo for this project it have successfully operate,Now my question is how can you combine many moisture sensor and many pump to operate in one project

  21. should we use only the 4 channels or we can use 2 channels also?
    please answer me quickly because i have to complete the project

  22. Sir, I’m making this project and I want to know the power supply of adruino board. So, please help me to get the power adapter for this project. Please suggest me. I’m very thankful to you for your kind support.

  23. sir i followed all the steps given above.there is no error while compiling and uploded completely but project is not working :(.please help me

    1. A relay is an electromagnetic switch operated by a relatively small electric current that can turn on or off a much larger electric current. So, you need relay only if you want to operate AC devices. You can directly send the signal (current) to DC motor, you do not need relay for that.

      Let me know if this is helpful.

  24. Sir my circuit is complete but the motor does not stop even when water is full in the pot .
    I also don’t know which variable should I put to describe the signal received from the sensor. But still the programming is been uploaded.

    1. You can send us your mail id to my mail so that we can Contact you if there any urgent need. I assure you that your mail id will be safe and not be misused.

    1. hi sir
      i want to supply water without using water sensor and i want to supply water daily at time to time . can u please give me the program

  25. sir can we use aquarium pump rather than ac motor??..what should be the code are we going to use??

    1. Hello sir, i use aquarium pump instead of the motor. Is it okay of i didnt use the relay?

  26. i need to use this as a school project but am lacking its research proposal, can you please get me a copy

  27. Sir Iam getting reverse of that
    When I placing soil moisture into soil water is coming after removing sensor water is not coming
    It’s doing reversly i have to submit with in 2days provide me answer fastly

    1. Hi. Can you help us? We are using this code but it didn’t work we are using a dc motor while the sensor is humidity sensor. Thankyou

  28. Hi
    Error shows me that
    ‘digitalread’ was not declared in this scope
    Plz help me to solve this

  29. how i use moisture sensor with LDR and write ardiuno code for this with its simulation

  30. hi admin i have some hours only to submit project on automatic plant watering system and the code you write above is done. but how i made simulation please help me if you can by sending video

  31. pls help me i need help in coding i will pay for the code/project.
    thanks and regards
    my mobile no. is 9811112460

  32. Hey, hi
    I tried to use the same method and code, but it is not working for me
    The motor is not working in both the connection, i dont see any results

  33. I can get the code to work everything functions just can not get the code to use more than 1 relay / pump.

  34. Dear Mr Rajkumar sir.
    Please make a tutorial for firebase iot eith esp 8266, control 4 channel relay by android application.

  35. Can u show how to run program & when program run is it automatically supply water to plants

  36. Please help! This guide and code is wonderful for my son who has successfully set everything up. But the motor runs whether the sensor is dry or wet. What are we missing?

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