This is an "It depends" answer. Your soil type, water pressure, and types of plants will all affect the watering results. Sandy soil will allow water to penetrate deeper faster. Clay soil will slow the penetration and allow the water to spread out farther. Water pressure can vary greatly, as can the length of tubing - each of which will affect how fast water will come out of the tubing. You should run the water and test at 15 minutes, 30 minutes, 45 minutes, etc. until the desired depth is acquired.