weekly watering number

Ever wonder just how much water your lawn and other plants need each week? From March - October, the Consortium publishes a weekly watering number each Thursday. 

Create a Weekly Watering Schedule
You may have heard the phrase "water lawns 1 inch a week." While this is a good general rule for most of the summer, weather is constantly changing and so should your watering schedule.

Step 1: Get to know your sprinkler
Over watering is the most common problem in home landscapes. Since each sprinkler puts out water at a set rate, knowing your sprinklers can help you determine when and how much to water your landscape.

You can use the Consortium Watering Gauges to figure this out. Here’s how:

  1. Place the Consortium Watering Gauge and 2­–5 other containers of similar shape and depth (e.g., tuna cans) at different distances from your sprinkler.
  2. Run the sprinkler for 30 minutes.
  3. Measure the total number of inches in the gauges/cans and then divide the total by the number of cans to get an average depth.
6 cans ÷ 6 inches = 1 Inch per ½ hour

Step 2: Decide when and how much to water
Since over watering is so common, we recommend creating a thorough but infrequent watering schedule such as before 10 a.m. or after 6 p.m. on Wednesday, Friday and Sunday.

table 2

Step 3: Use local weather conditions to help determine watering needs
Watering smart means thinking like a plant by using local weather conditions to help determine how much water your plants and lawn actually need. Use Consortium’s weekly ET number to determine how much to water during each time on your schedule. Here’s how:

  1. Divide the weekly ET number by the number of times you will water that week.
  2. This is the amount (in inches) you will water each time during the week.

For example: An ET value of 1 means your lawn should get 1 inch of water that week. If your sprinkler waters an inch each half hour, you will set your sprinkler system to water .33 inches each time (or 10 minutes using the example from step 1).


table 3

Some key things to remember when using ET as a guide to creating a watering schedule your landscape include:

Step 4: Tailor your watering to plant needs
Water needs vary from plant to plant. For example, turf generally requires more water than plants, shrubs and trees. Setting your sprinklers to water turf separately from shrubs and perennials will allow you to tailor your watering schedule for each major section of your landscape.

Determine which plant types are located in different areas of your yard and then use these general guidelines to create watering schedules to fit the needs for the different zones in your yard:

Table 4

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