Here's my plan to water my garden/yard while i am away for 3 weeks in April.  Get a 55 gal plastic drum and set it up on the brick wall corner of the yard.  Hook a tube from the water spigot to the top of the drum. Right, so now water gets into the drum at the rate i choose as i turn the lever at the house. 

At the outer base of the drum some tubing to the various plants, etc. But what i want is to let the drum fill to near the top, then open a valve automatically to let the water out. Once the drum is empty the valve closes and refill takes place.  The inlet water is never off. The yard is watered at one go, every 2nd day, or as the inlet rate is modulated. 

 

What i need is some ideas of how to open the vavle when full, then close.  The toilet tank idea is fine but backwards as it stops when full.  My tank must open when full and close when empty.  I thought maybe a 'mercury switch' if any exist for this task. 

 

Ideas, plz.

How's your mains water pressure? (or do you have a pump).

 

There's loads of timers that you can put onto your water supply which can be set to water at set times for specific periods.

 

No real need for a tank unless your supply is erratic.

Just now, Crossy said:

How's your mains water pressure? (or do you have a pump).

 

There's loads of timers that you can put onto your water supply which can be set to water at set times for specific periods.

 

No real need for a tank unless your supply is erratic.

Erratic?  Very much so.  Lots of pressure during the night, not so much in morning.  My plan may cost more but IMO, less likely to totally fail.  

 

I will investigate the timers.

In that case, yes a tank is needed. Buy a cheap purpose made one, less hassle.

 

You'll also need a pump, I doubt gravity feed is up to it. A cheap automatic pump and one of those timers is a simple and effective solution. You can also plumb it into the house for sensible water pressure at all times.

 

It's only 3 weeks, can you pay a neighbour to water the plants?