It is getting hot in Bay Area and my new lawn is doing well, mostly.
I can't help but notice that I have a few dry spot on my irrigation system.
The grass there are stressed.

The MP rotator works pretty well, mostly. The dry spot is two folded.
One reason is that there is one triangle is a little straching and MP1000 can't
actually reach it. It is one feet sort. I also notice that on the last feet is not
getting good enough water, kind of like soft edges.

The other one is cause by the grass blocking the MP rotators. My pop up
is 6 inch. I cut at 4 inch. In theory it should be good enough. But the grass
close to the nozzle grow too fast, the mower did not cut low enough on
that spot because the concrete surface around it. MP rotators has a one
of the stream shooting downwards to cover the close area. If the grass get
to 5.5 inch, it can block that stream. Which cause the close grass get more
water and grow even faster. The dry spot is about 2-3 feet away.

So the lesson is, always respect the head to head coverage and give some
clearance for MP rotator to do its work.

Any way, I replace three of the MP1000 into MP2000 to get more distance.
The nice thing is that, you can mix MP1000 and MP2000 in one zone.
That is just wonderful for me. After reduce the MP2000 distance. I can get
a pretty good coverage. Consider the front of the lawn water evaporate faster,
the MP2000 give a little bit more overlap so it should compensate for that.

If I do it again, I would zone the front and the back of the lawn into different
zone due to the shadow of the house. That way can match my water evaporation
with zones. I will wait and see how my current system hold up. Hopefully no
more obvious dry spots.

I still like the MP rotators. Having the option to upgrade to MP2000 to get
more distance is great.

ssa,

I have some areas with a 12 foot radius/square spacing. I am thinking about 30PRS heads and MP1000 nozzles. I also have an area that I'm planning 17-20 foot radius/square spacing using PRS40 heads and MP2000 nozzles. Based on your experience, does this sound ok? Thanks.

mike,

I think he 12 foot radius with MP1000 is fine.
17-20 foot using MP2000 might be a little bit tight.
The vendor tend to stretch the reach number on the manual.
(high water pressure, perfect no wind etc). I found it
works best treat the average of the claim reach range
as your max design range. That give you some room to
play with.

In order to give a good even spray, you really need to over
shot about 1 foot or 2 on the edge. The spray pattern is
not going to give you shape cut off on the edge of the pattern.
So in order to give the edge grass even chance of water,
You really need to over shoot a little bit.

BTW, try to use triangle spacing as much as possible.
Triangle spacing give better (even) coverage than square
spacing. Only use square coverage if you have no other
choice. Another thing to keep in mind is that, square
spacing and triangle space give different precipitation rate.
The different is about 10 - 15%, not huge, but noticeable.
You don't want to mix them in the same zone.

I have no experience using PRS heads. I like my MP rotators.
That is, if the grass was cut on time. I like the MP2000 more
than the MP1000 series. MP 2000 has less grass blockage problem
because the water stream shot upwards. In MP1000, one of the
stream shot downwards.

Thanks, that helps a lot. have you tested the actual precipitation rate? if so, how close is it to the spec sheet?

also the PRS heads I am referring to is the body that the nozzles go into. I will probably use the 40 psi model.

mike_44012 wrote:Thanks, that helps a lot. have you tested the actual precipitation rate? if so, how close is it to the spec sheet?

also the PRS heads I am referring to is the body that the nozzles go into. I will probably use the 40 psi model.

I checked it on mine--it's nose-on for my pressure. They really aren't kidding about those things being pretty forgiving about pressure.

mike_44012 wrote:Thanks, that helps a lot. have you tested the actual precipitation rate? if so, how close is it to the spec sheet?

also the PRS heads I am referring to is the body that the nozzles go into. I will probably use the 40 psi model.

I haven't test my precipitation rate. My impression seems pretty close.
I learn it the hard way. I program my according the spec for 1 inch water
per week. But I make a mistake. With 2 zones (even they overlap with
some of the area), I need to double the time. So I end up spraying
1/2 inch per week. My grass have stress on the water thin area.
So I increase the frequency of the water eventually it match up with the
true 1 inch water caculation. Then I realized where I forget the factor of 2.
The number match with spec pretty well.

Oh, I did not use PRS heads. However I suggest using 6 inch pop up
instead of 4 inch for the MP1000. I need to cut my grass often even with
6 inch pop up otherwise I get dry spot from grass blocking the close spray
stream. I think PRS heads would be great.

Yea, i guess the precip rate is the one disadvantage with these but I think the pros outweigh the cons. Since my front yard is almost a perfect square, I want to use square spacing the so the precipitation rate would only be .39. This means I would have to water for 2.5 hours for an inch! I'll have 2 zones in the front so i figure I'll start at 1:00 AM and finish by 6:00 AM.

My flow's kind of limited--I only get 6.5 GPM at 45 PSI. All of my zones require two hours or a bit more, for the most part. Inconvenient, but workable, and with 6 zones I have to water for 12 hours plus.

I either start the front at 6 PM when it's more shadowed, or break it over two nights.

mike_44012 wrote:Yea, i guess the precip rate is the one disadvantage with these but I think the pros outweigh the cons. Since my front yard is almost a perfect square, I want to use square spacing the so the precipitation rate would only be .39. This means I would have to water for 2.5 hours for an inch! I'll have 2 zones in the front so i figure I'll start at 1:00 AM and finish by 6:00 AM.

Why do you use the square spacing to get the precipitation rate lower?
That seems to be a hack, not very good one. Evenness is the No.1 design
goal. Nothing else matter as much.

If you want slower precipitation rate, Isn't that is some thing you can do with
a timer control? Irrigation for 4 mins and rotate to the other zone. I haven't check
the irrigation control on the market. I write my own irrigation program in an OpenWRT
router. I am do whatever I want with it.

If you have a big lawn, the time it takes to irrigation should just limit by the
water flow from the main pipe. If the nozzle give lower precipitation rate, that
means you can install more of them in one zone. The end of the days the precipitation
rate of the nozzle shouldn't really matter. If you have very limited number of zones,
you can't just add nozzle to a zone. Since you have 2 zone, the factor should not
be bigger than 50%. If it is, that means you should be able to turn on both zone at
the same time.

BTW, I am very happy with my irrigation program (other than the 50% mistake I make.)

Sorry, I didn't explain my point very well. My goal is not to lower the precipitation rate. I think that the MP Rotators have a lot of very nice features but the disadvantage is the low precipitation rate. On second thought, that may be considered an advantage because it promotes less runoff.

My front lawn is small- 34x34. I will probably use 9 heads at 17' spacing. I definitely agree that triangular is more even. However if I do triangular spacing in a square yard, I would be left with some odd areas to deal with on the sides. I think triangular works better for larger areas or ones that have an irregular shape. I may use triangular when I do my back yard some day for those reasons.

More update. I am still fighting small area of dry spots.
It seems to me that the MP2000 series still have a bit uneven
regarding the close area. The area which is 3 - 4 feet away
doesn't seem to get as much water as it deserved. That area I
still have visible dry spot. Now the summer is officially here.

ssa wrote:More update. I am still fighting small area of dry spots.
It seems to me that the MP2000 series still have a bit uneven
regarding the close area. The area which is 3 - 4 feet away
doesn't seem to get as much water as it deserved. That area I
still have visible dry spot. Now the summer is officially here.

I find the same even with the 3000 series. My solution was to go much closer than head to head on the spacing of those (and fortunately they have a low output so that's workable) so I could cover the first five feet of each with the distance output of the next one.

MorpheusPA wrote:I find the same even with the 3000 series. My solution was to go much closer than head to head on the spacing of those (and fortunately they have a low output so that's workable) so I could cover the first five feet of each with the distance output of the next one.

I wish I know that earlier. Now with all the grass growing and the
pipe under 10 inch of soil, it is hard to add another head.
I feel like idiots when I water my dry spots with garden hoses.
The thing is, the automatic system works very well on non dry
spots. I don't have patient to give the dry spot enough soaking time.
That is my irrigation controller was for.

The rest of the grass hold up very well for 4 days without watering.
I found some yellow, weak, dying grass. After close inspection
(using the microscope), it is not TTTF!

Even the dry spot hold up pretty well after garden hose watering.
Now I just need to go out water it every 4 days for a few dry spots.
There is always something isn't it.

Yeah, adding the extra MPs weren't a lot of fun here, although at least it's a task you only need to do once. And in my case, only on the southern face (the northern also uses MPs, but requires far less water).

I just retrofitted 36 spray heads in my back yard to MP Rotaters and overall I am impressed. I have a very undulating and curvy backyard so they fit the bill perfectly. Sold it to the wife by showing her a video of them and explaining how much fun our son would have running through them. It backfired as now all the kids around our house want to play in them. Overall I think they are great when limited water is needed. I'll stick with my Rainbird 5004+ PRS SAM rotors for my front and side yards as more water is needed and the throw is much longer.

Ditto here. I put them on the south face (more water-demanding actually) because it's a slight slope and tends to go into runoff faster. That doesn't happen with the MPs. I do have to water longer, but no problems there.

The rest is Hunter PGPs with blue nozzles, which I love, and work well everywhere else except the north face front (shorter areas there). I use MPs again in that zone.

MorpheusPA wrote:Yeah, adding the extra MPs weren't a lot of fun here, although at least it's a task you only need to do once. And in my case, only on the southern face (the northern also uses MPs, but requires far less water).

In my case, my dry spot has been spreading near the edge of the grass
boundary. It is not some thing I can fix by just adding one or two head.
I will consider that if I ever going to renovate this TTTF lawn. So far
that is a non starter in the wife department.