When I was running drip irrigation in my big garden I used 1/2 gallon per hour emitters. I would water for about 3-4 hours. After this amount of time the soil was saturated out to a distance of about a 1 foot radius of the plant. It is impossible to say just how long a time is appropriate for your soil as all soils are different but if the soil is saturated that is usually enough. Depending on the weather I would normally water about every 10 days. You can tell when a plant needs water if it is a little wilted in the AM hours. You cannot water a plant too much at once but you can and will kill a plant by watering too often. Just stick you finger into the soil about 2-3 inches deep and if the soil is DRY, not slightly damp, it is time to water again. But as I said earlier, if the plant is a little wilted in the morning hours it is time to water again.