Of course this statement depends also on the size as well as the kind of garden you are growing. But for most yard gardens, you can manage your garden, once it’s set up, in as little as 3-5 hours a week.
Once your garden is all set up, you can save time managing it by an efficient watering system. You will find that your garden will grow much more efficiently once you determine how much water it really needs. Random, over watering or under watering can be detrimental to your outcome.
There are several watering methods and tips to consider before you decide what’s best for your size and kind of garden. One method that can be used in a part or all of your garden is soaker hoses with a timer.
According to the article in Rodale’s Organic Life, “Studies show that well-designed drip irrigation systems use at least 30 percent, and in some cases 50 percent, less water than other methods of watering such as sprinkling.”
http://www.rodalesorganiclife.com/garden/top-10-ways-conserve-water
https://www.rodalesorganiclife.com/garden/how-install-rain-barrel