how long should you water your lawn per zone
Turn on the sprinklers for 20 minutes and use a ruler to measure (in inches) the depth of water in. each can. Now determine the average depth in all of the cans. Multiply the average depth by 3 to. determine how many inches of water your sprinkler system applies per hour. Step 3. Determine how many minutes you need to water your lawn each week. Scientific. research has accumulated data on how to water cool and warm season grasses.