Lawn Irrigation Misinformation
 

I am always bemused when I see or hear a "professional" give advice on lawn irrigation times. My lawn service guy leaves a note telling me how long and how often I am to irrigate. A master gardener included a chart of watering times in a recent issue of the VHA "Villages Voice". They give this advice having no idea of the extent of my system.
They do not know the size of my spray nozzles. My Hunter rotaries come with twelve interchangeable nozzles ranging from 0.7 GPM to 12.7GPM @ 50 PSI.
They don't know how far they spray. The range of these Hunters are 22 to 52feet. The range is reduced by containing the distance without reducing the GPH flow.By setting back the range you increase the coverage per square inch.
They don't know area they cover. My rotaries cover from 90 degrees to 180 degrees on the same zone. Assuming the same size nozzles and same range, the 90 degree head will deliver twice the coverage per square foot as the 180degree head.
They don't know the layout. My system was installed prior to my purchase. It was very well laid out so the heads cover from head to head.
They don't know my type of soil. In fact, my soil varies from one area to another. Sandy to loamy to clay.
I have been managing a St. Augustine lawns ( four different homes) for 29 years. I have found the only way to calibrate my sprinklers is to use a rain gauge at numerous places around the lawn. I also watch for spots that show distress too soon (it usually means it needs more water). I adjust times and change nozzles as indicated.
It takes a while but it is worth the effort.
Don't mean to preach but some of my neighbors have had their lawns ruined by following the advice of so-called experts.

I Agree!
 

DE... I'll second that! Being new to the St Aug. lawn I was a little befuddled when we moved in last fall but a little study did the trick.
Univ of FL recommends 3/4" to 1" of water per week which you can only determine by measuring as you stated.
I had a lawn service who kept telling me to water more even tho I was set for up to 1.25" at one time.
I quickly concluded they didn't know what they were talking about and gave them their walking papers. As soon as I started my own granular fertilization AND cut back the water to 3/4" per week INCLUDING rain we started doing just fine.
Because of our water shortage situation, not to mention the cost (8,000+ s.f. of lawn), I am sensitive to over watering. I found that by monitoring carefully I was able to significantly reduce may water consumption.
Bottom line is I'm not convinced the lawn people really know what's going on. We've continued with our own fertilizer and bug program and have actually had the water off for most of the summer. Lawn looks great!
Also, past experience has proven to me that longer is better and that unless you get after them the local "mowers" will cut short. I have been told that one of the lawn maintenance companies encourages a shorter cut. Is this to sell more chemikcals and treastments?
We keep ours at the longest the mower allows, about 3 1/2". A longer lawn will retain moisture and fertilizer better.

Downeaster,
You are one of the gems I keep finding in TV! Quiet folks who know tons of stuff about a topic or two. Something piques their interest and they answer with a PhD's worth of info on a topic. I'm very impressed about what you know about irrigation. Even though I'm not having problems with my system I'd like to hire you to take a look at it. Could we please do this soon before everybody else recognizes your talent and I have to pay triple for your services?

I assume you say this in jest but, in the event you are serious, I am not for hire. It is all I can do to keep up with my own yard work.
Glad to hear your system is working OK.
Thanks for your kind words.