Potted plant watering system. (Involves water pumps.)

Using Arduino Project Guidance
81

I'd like to take a crack.

void loop()
{
        int i;
        //digitalWrite(1,HIGH);            //  With this line active, LED 5 doesn't glow.
        for (i=0;i<5;i++)
        {
            digitalWrite(LED+i,HIGH);
            delay(500);
            digitalWrite(LED+i,LOW);
            delay(500);
        }
        //digitalWrite(1,LOW);            //  With this line active, LED 5 doesn't glow.
        delay(2000);                       //   Just a longer delay to simulate the long time between waterings.  For now
}

Notes:

  1. You don't need the while(1) loop. Your loop() already is the infinite loop.
  2. I think the LED+i+1 line was accidentally left in.
  3. LED 5 should get turned off after the watering sequence. I put a 2 sec delay in so you could see what I think you mean,
    that LED 5 indicates that a watering cycle is in progress.

Post if this doesn't do what you want.
Good luck. Keep plugging.
By the way, I water my house plants with a 20 ft coiled thin hose connected with a valve under the sink.
I think gravity will not be forceful enough. I give each houseplant 12 sec twice a week.
You can cannibalize a cheap battery operated faucet connected sprinkler timer to get the solenoid already connected to valve that can
switch water under presure.
(Ex. http://www.amazon.com/Orbit-Hose-Watering-Timer-62024/dp/B0013I2MLS/ref=lh_ni_t
If you need a bunch of them though, it starts to add up. You don't really ruin it. If you set it to On, remove the battery(s), and bring out two wires for power then when you provide power, via a digital out, you get a strong flow of water. I have a similar one. They're geared; the turn on/off is not instant but takes about a second.)