Go to Home Depot and buy a fancy digital timer. You can set day, time, everything down to a tee, I think they are like 40 or 50 bucks.

Then hook up a water pump to it with some hose going to and from the water to your MJ.

The pump will only run for the time you specify, just make sure you only put enough water in the resevoir so you do not over water your MJ.

Do a test run first...

Just an idea, and trying to help.