Plant irrigation system I'm very new to the Arduino game I wanted to make a small auto watering system for my plants. I bought these items 


5V 1 CHANNEL RELAY MODULE FOR ARDUINO PIC AVR DSP ARMB
9 VOLT BATTERY SNAP CONNECTOR B
ARDUINO UNO R3
CAMELION 9V BATTERY SUPER HEAVY DUTY
PIN TO HOLE DUPONT 40 PIN 30CM ARDUINO JUMPER WIRE 12 INCH
SOIL MOISTURE METER FOR ARDUINO. 


I followed a video on youtube I attached the guys circuit diagram as well. After following instructions my pump wont turn on I also programmed it as well. Please help if anyone can show me how to rewire the device and codes or if I'm doing something wrong. Please help.

int Relay = 13; 
int sensor = 8; 
int val; 
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); 
  if(val == LOW) 
  {
    digitalWrite(13,LOW); //if soil moisture sensor provides LOW value send LOW value to relay
  }
  else
  {
    digitalWrite(13,HIGH); //if soil moisture sensor provides HIGH value send HIGH value to relay
  }
  delay(400);
}
I've seen so much fake projects from "Viral science". I'm not sure whether he/she simply don't know what he/she does or if he/she simply tries to trap people. This project is a race condition itself ;-).

Besides your battery is empty. I don't think it is a big problem to use a 9V block battery, but Gerben is right, it won't do its job for very long. Have you thought about using a LiPo or LiOn Accu and a Solar loader?

There are worse things I see: 

The sensor is powered by 3.3V but you read the ON/OFF signal with a 5-Volt Pin. That could be a problem, if there are other voltage drops that lead to a signal the PIN can not recognize as HIGH. Check the documentation of the moisture sensor and if it allows 5V use 5V to power it. All sensors I have found on Google have at least a range from 3.3 Volt to 5 Volt. 

Check the current consumption of the relay. It must not draw more current than the Arduino PIN can provide (40mA for the UNO). And, don't use PIN13 to switch the relay. There are so many others and PIN 13 is connected to the onboard LED, which draws 10 - 20 mA on its own.