SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I don't have any old manuals around, but I know for a fact that they did not recommend head-to-head triangular spacing. The 20 foot spacing on the old all-brass sprays would work out to around 70 percent. Those systems worked. They worked extremely well.

As for the wasting of water, I would want to see genuine proof of that. Side-by-side comparisons of identical properties. Not just conjecture and speeches. Every time a tree gets in the way of someone's 'perfect' head-to-head layout, some of the lawn doesn't get its share of water. Would you install extra sprinklers to make up for it? Cut down all the trees? Or maybe run the zone for the extra time needed for the area getting the least water to receive what it needs? The last option is the one that works in the real world, however the water usage is affected.

You'll still get head to head coverage with triangular spacing if your spacing at 50% of diameter (like you would with square spacing). Many older systems that used triangular spacing simply streched the spacing to 60% or even to 80% of diameter. So these systems had very poor uniformity. All one had to do was up the time on the controller as an easy fix-but that wastes water.

Just cut down every tree that you ever encounter, and the mathematical perfection of your head-to-head layouts will be ensured. While you're at it, insist that all slopes be regraded to near-flat perfection. Because, as has been vigorously expounded, the sprinkler layout is the all-important concern, and no others need apply.

Meanwhile, back in the real world, all those triangular-spacing layouts are still covering their lawns. One can be reminded of all the aeronautical analysis that was done in respect to the flight of a bumblebee, and how the scientists would claim that their calculations insisted the bumblebee could never fly.

Funny thing, if you get your hands on some older manufacturer's catalogs, you will see their technical sections describing system layouts with triangular spacing, and not head-to-head square spacing. Kind of makes you wonder when they figured out that a change in layout philosophy would sell more sprinkler heads.

49'x 82', unless you've got a tremendous amount of PSI, at least 50 would be ideal to start, I don't think 6 will cut it. At the very least 8 on the edges to get the job done with proper coverage. If you've got the pressure then 6 could do it, but the heads had better be either a Rain Bird Falcon/7500 series or Hunter I-25/I-40 series. X factors include hills and trees.

People cut back on rotor spray distance for a number of reasons. A rotor spraying 25-30 feet is less effort to install than the equivalent number of sprayheads, and might accomplish something the sprayheads couldn't, like spraying over some obstacle too high for a sprayhead to clear.

Wow, I don't know what to say. Are you saying to cut back the distance on a rotor so it performs like a spray head? I'm just spitballin, but I think that might be a waste of money. Hey, if you poke enough holes in your garden hose, you can run that at the same time as your rotors and sprays too.

Reduce the distance and arc, and a rotor can match a spray. Also, restrict the spray, by either a pressure-regulating body, or an under-nozzle restrictor, and the match is easier. The last can be employed in an instance of needing one or two small strip sprays to complete the coverage on a lawn being watered by rotors running at higher pressure.

Mixing the two is not something you'd do as a first priority, though. But in cases where there is not enough sprayhead flow to match a well's output, combining them with rotors (properly nozzled) is a valid design technique.

I have yet to see a rotor that can match the precip rate of a spray.

Yeah, I'm doomed. (and I still want to know how many rotors the head-to-head gurus would place in a 60-foot diameter lawn)

By the by, it is perfectly okay to mix rotors and popup sprays, provided you use extra-large-size nozzles in the rotors, which will make them match the sprayheads' precipitation rate.

There isn't anything wrong with head-to-head designing. I just haven't ever seen a homeowner with a decades-old lawn sprinkler system, using triangular spacing, that wanted to rip it all out. The landscape is green and healthy from corner to corner. Why change? When one of you young pups convince them to change over, let us know.

you'll never make it in this business wetboots