How to Water 1 Inch Per Week

Most of the time, lawns only need 1 inch of water per week or a little bit more if the weather is especially hot and dry for more than a few days at a time.  Generally, this amount of water is plenty to penetrate the soil 6 inches below the surface, establishing stronger roots to help the lawn weather the dry season.

South Fork Water Board values the way healthy lawns add to the beauty and livability of our communities, but would also like to provide its customers with the tools to make the most efficient use of the water we use. By following the simple steps below to figure out the flow of your irrigation system and how to achieve watering 1 inch per week.

Find Out How Much Water Your System Puts Out:

• Set 5 empty tuna cans (or something similar) at various places on your lawn within your sprinklers range. Place the cans halfway between the sprinklers and in the areas that generally receive the least amount of sprinkler water.
  
  
• Turn on your sprinklers for 15 minutes.
  
  
• Measure the depth of the water in each can and record on a piece of paper.
  
  
• Determine the average depth.
  For example:
  can #1 __ +can#2__ +can#3 __+can #4 __+can #5 __= for a total depth of _____.
  Divide the total depth by 5 = for an average depth of ______.
  
  

• Using your average depth from above use the chart below to determine your watering times. The “Inch” Chart
  Number of minutes to water to get 1” of water per week.

The Inch Chart - Number of minutes to water to get 1" per week

Over watering causes 75% of turf problems!Signs you are overwatering your lawn:

• Soil is constantly damp
  
• Grass blades turn a lighter shade of green or yellow
  
• Young shoots are wilted
  
• Moss and mushrooms are growing

Determining your soil type – Can also help determine how much water you lawn needs. Whether it is clay, sand, loam or a combination, its important to know your soil type. The rate at which soil absorbs water is called the “infiltration rate”. The chart below shows what to expect for each type of soil.

Use the infiltration rate, along with the amount of water your system puts down in a give amount of time (the precipitation rate), to help determine how much time to spend watering each week.

Getting ride of puddles and run-off  – If water puddles or runs off to another part of the landscape, your soil probably has a high clay content. To get the most out of watering, divide the total watering time by half, and add a break in between. For example, if the chart recommends watering for 40 minutes per week, water for 20 minutes, break for 2 hours, then water for the remaining 20 minutes. Consider installing a controller for an automatic system that can be programmed for multiple start times or installing a timer at the outdoor faucet to make this an easier job.

If there are still problems getting water to penetrate the soil, the lawn may need to be aerated or thatched. Yard and garden centers in many areas carry the right tools for this job, as do many equipment rental companies.