In my opinion (probably wrong), most people do more harm than good by watering. They sprinkle a few drops on the surface to tempt the plant to send its roots up into the surface soil, where they dry out and die. Unless you intend to give things a proper soaking, you will do more good by hoeing, to reduce capilliary action bringing moisture to the surface, on hot dry days (better still in the sun to dry out any weed seedlings) and only water when the surface is moist but the soil beneath is dry, the sky overcast. Mulching to reduce water loss is also a better bet than sprinkling crops in the open soil, IMO. None of this, of course, applies to containers, where you can get a useful amount of water to the roots.
