#define watering 7
const unsigned long day_since_watering = 30000L;
const unsigned long time_to_water = 5000L;
unsigned long startdate;
unsigned long currentdate;
unsigned long start_water_time;
unsigned long current_water_time;
bool pump_on = false;

void setup() {
  pinMode(watering,OUTPUT);
  Serial.begin(9600);
  startdate = millis();
}

void loop() {

  currentdate = millis();
  if((currentdate - startdate >= day_since_watering) && (pump_on == false))
  {
    digitalWrite(watering, HIGH);
    pump_on = true;
    startdate = currentdate;
    start_water_time = millis();
  }

  current_water_time = millis();
  if((current_water_time - start_water_time >= time_to_water) && (pump_on == true))
  {
    digitalWrite(watering, LOW);
    pump_on = false; 
    start_water_time = current_water_time;
    startdate = millis();
  }
}