Sprinkler Clock Programming

Just having an automatic sprinkler system alone will not guarantee success—not even a good one. The clock absolutely must be programmed correctly. Otherwise, you won't receive the value that you paid for. Additionally, the default program that the sprinkler controller came with almost ensures failure. It has not been optimized for specific landscape conditions.

Watering conditions

Every sprinkler controller has to manage the following conditions. The brand, model, and manufacturer don't matter.

  • The plants or lawn to be watered and how much they need
  • What kind of sprinkler and how fast it applies water
  • How many times to water in a given week
  • How long to water at each run time
  • How many run times per day
  • Seasonal and localized weather variations

Ouch! Can't this be made more simple? Let's try to focus on what really matters. Then when you read the manual maybe it will make more sense.

What really matters

Use programs

It really helps greatly to break up the different types of sprinkler circuits into groups.This helps to more easily apply the total amount of water according to plant needs. Most commonly the controller will look something like this:

  • Program A - Lawn
  • Program B - Shrub beds
  • Program D - Drip irrigation

Adjust watering duration by the type of sprinkler head

Sprinkler heads come in two basic types, a spray head and a rotar type of head. Let's look at the important differences.

  • The spray head does not vary the pattern of water. It just sprays out. It dumps a lot of water on the ground fast. Soon the water can begin to run off. Because of this you can't water for very long with this type of sprinkler, generally no more than 5-7 minutes.
  • The rotar head moves a stream of water back and forth over an arc. It applies the water much more slowly. Generally there are no run off problems and you can run it as long as you want.

How many times per week to water

  • Generally established shrubs only need watering a couple of times per week, say Monday and Thursday.
  • Lawn on the other hand needs watering about three or four times per week. It can be done daily but be careful not to overwater.

What about multiple start times in a given day?

If there are any spray type sprinkler heads, it is probably best to use multiple start times in one day. Why? Otherwise, water will begin to run off and will be wasted. Think of it as a heavy rainfall where water begins running down the street. Not a good idea. When a 2nd or 3rd start time is used, time will be allowed for the water to soak into the soil between watering times. Think of it like frequent light showers in the spring time.

So what does this look like?

Scenario 1: All the lawn sprinklers are rotars and only the lawn is being watered.

  • All the sprinkler circuits (or zones) will be on program A
  • Water on Monday, Wednesday, and Friday
  • Make only one start time at your choice such as 5:00 AM when there is no wind.
  • The run time might be 30 or 40 minutes. You'll have to play with it to find out how much is needed.

Scenario 2: Same as #1 except there are also some spray type of sprinklers. This adds a huge change and affects the program in a very big way. In fact this is where most people including contractors fail! Why? You will need multiple start (or run) times for those spray type sprinklers to avoid the run off problem. Here's how to do it.

  • All the sprinkler circuits (or zones) will be on program A (same as above)
  • Water on Monday, Wednesday, and Friday (same as above)
  • Now you need multiple start times, such as 5:00, 6:00, and 7:00 AM when there is no wind.
  • The run time will be shorter. The rotar heads might be 10 or 13 minutes; whereas the spray heads will run for 5 - 7 minutes. Again, you'll have to play with it to find out how much is needed.

Scenario 3: Same as #2 above except now let's add in some shrub sprinklers of the pop-up spray type since these are the most common. Now the reason for multiple programs comes into play. Leave program A alone. You could think of it as an entirely different sprinkler system with its own clock.

  • All the sprinkler circuits (or zones) will be on program B
  • Water on Tuesday and Saturday. Note that this day differs from the above and does not overlap. You'll see why next.
  • Make two start times at your choice such as 5:00 and 6:00 AM when there is no wind. But wait, didn't we use those same times already? Yes, but on a different day! Thus there will not be a conflict. Using a different program makes this possible.
  • The run time might be around five minutes. Water starts running off quickly in shrub beds.

Exceptions

  • If you have annuals they will need to be watered every day in all likelihood.
  • Similarly potted plants and hanging baskets will almost certainly need daily watering.