Blast - sorry

Sounds like what you need is a watering timer. These are small self-contained, battery operated, solenoid valves that are activated by a digital timer. These can often be set up to activate for a established watering time on certain days of the week. I've never had one but a neighbor ran one for years.

It was a smallish unit that screwed onto the hose-bib that took a nine volt battery to operate.

There is also a simple mechanical one that allows you to manually turn the water on and set the valve to close in some number of minutes. The one I saw allowed a run time of up to four hours. This is essentially an egg timer that works a valve to turn off the valve when it goes off so you don't have to remember , or bother, to turn off the water.

Most hardware stores have them and they run $15 for the mechanical unit and $40 and up for the electronic one.