Mixed emitter system - worst case scenario

Hello all, trying to get a “fix” for a poor situation. We moved into our house last February. After we bought the house, we realized the previous owners went “cheapest route possible” to “finish” the newer build with landscaping so they could sell it. Poor sprinkler spacing. WAAAAY too many heads per zone (averaging 8-12 hunter PGP’s per zone - literally all set to the default 2 nozzles regardless of spray pattern). Cheap rock. 5 valves crammed into a small sprinkler box with one sticking out of the side (seriously!). The ENTIRE perennial beds, shrubs and trees are on a single drip line. Anyways, I spent the whole year working through the flex daily schedule getting it running appropriately and after switching the nozzles to appropriate flow rates and scaling them WAY down to try to get decent spray patters, while also changing out the entire backyard to low pressure mp-rotators, I think I finally have the yard being covered… at least all of the grass is green.

Now that the backstory is out of the way for context here. I just had to do some maintenance on the drip line because I realized it wasn’t running at all (grrrrr). Something happened since I fired up the spring sprinklers. Well, while getting it back up and running, I realized that they used a mixed emitter system on the drip line. Aka 4gph DIG emitters on the trees, 2gph emitters on shrubs, and 1gph on all perennials… Anyone have experience on what might be the best settings to run this thing at? I realized I was probably WAY overwatering shrubs and trees last year as it was running for 1 hr or so 2-3x per week. I have decently dense clay soil as well. Feel free to ask me what questions I may be leaving out, but I was thinking of setting the zone up as “shrubs” with silty-clay as the setting and adjusting the nozzle rate to 1.5" per hour seems to be a ballpark average for a mixed system between 4gph and 1gph.

Thanks in advance for help.

Boy, it is going to take some work to get this system to work well. The good information here is that they at least sized the nozzles according to the plant type, but trying to run perennials and trees on the same zone is going to be REALLY tough. Perennials need very frequent watering (daily in some cases), while trees can go as much as a week in even the hottest climates. Typically you would water based on your neediest plants, which in this case would be the perennials, but that is going to come as a huge detriment to the health of your trees IMO.

Is there any chance you could run a second drip line for the perennials? If you left trees and shrubs together, while not ideal, would be somewhat doable.

Also, is there just one emitter per plant?

First off, thanks so much for the time to respond. I really appreciate it! I’m a newer homeowner so everything is still very new to me. Just trying to do my best.

I just don’t think there’s any way I can run a second drip line. I’ve had 3-4 different landscaping companies look at our system and it’s brutal the quotes they come back with to fix it to run another line due to our rock beds and concrete edging around all of our yards. It’s a pretty design, but quite complicated. So will the overwatering encourage disease in the trees then?

Yes, only one emitter per plant

Heh, I feel your pain because my backstory is very similar. The only difference, I think, that the previous owners simply did a lousy job installing the irrigation system as it’s been in place for years. Just the other day, I found a leak in a cracked PVC pipe that they left exposed on the surface. They used this pipe to extend a lawn zone to water trees. How do you like this beauty:

My plan is to eventually segregate as much as possible by plant type. I’m going to use this opportunity to move the trees from the lawn zone to another nearby zone that has only trees and shrubs. Then I’m going to convert that entire zone to drip (it’s on bubblers now). But I too have a hard time understanding how to make Rachio work with GPH of spot irrigation instead of IPH of wide area coverage. I’m watching this recent post: Struggling to get settings right for drip - Schedules & Zones - Rachio Community hoping that someone will chime in with good insights.

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It is possible. You might need to water as much as daily (not sure where you are or how hot it gets) to keep the perennials happy, which best case scenario will cause the tree roots to stay VERY shallow (side effects would be root bulging at the surface, pushing up on neighboring concrete borders/walls). Worst case would be that the daily watering would never give the roots a chance to dry out, and could cause root rot.

For what it is worth, this chart that was put out by the “Water Use it Wisely” group shows what is “recommended” for best watering practices. The issue is going to be getting the trees enough water in the run time required by the perennials. The mix of emitters isn’t ideal the way they are. Based on this chart, your perennials should get .5 gallons each watering, which would make the run times 30 minutes, but 30 minutes with the 4gph on the trees is only going to net you 2 gallons and depending on average canopy size, that isn’t nearly enough water for the trees. Then, we need to figure out how to break up the watering so that the perennials can get multiple waterings a week, while still applying enough water to the trees.

As you can see, with relatively small plant sizes selected, the run time that each plant “need” are totally mismatched. Now, run time is assuming you had the ability to run each plant type separate and only watered the trees every 7-14 days (as needed), and the perenials 2-3 times a week (as needed), but it gives you an idea…

Wow, left the sprinkler swing joint in place and all!

Lawn and trees will never have the same watering needs! :rofl:

Oh, I didn’t even occur to me that that’s a swing joint … with 7 elbows and all. Seems a bit excessive :smiley:

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Well, gross. The one good thing I have going is that the majority of the trees are aspens (which like moist soil). I think the only ones I’ll have issues with will likely be the Bradford linden and the crabapple. All of the trees are relatively young, so maybe I can get by another year or two on the current system then possibly allow them to get water naturally. Ugh.

Thanks for the link. This is very useful and I think it will finally help me configure Rachio. The only remaining question: Are these numbers “per week” (the page for some reason doesn’t seem to mention if given water needs are per day, week, month – unless I’m missing something)?

I still think you might need to take some time replacing emitters. I’m a fan of the Rainbird emitters, and have good luck with them. They make .5gph emitters that might need to go on the perennials to get the total watering run time up to 1 hour. Then, assuming your system has the capacity to do it, bump the tree emitters to maybe 10gph, and the shrubs to 4. I think that might balance the system out enough, and in a weeks time, would put out the required water to each plant type, assuming 2-3 days a week run (need of the perennials).

That’s fantastic insight. Thank you so much Troy.

Technically, it is “as needed” when the root zone of each plant type is “dry”. The frequency needed will change throughout the year based on weather and temps (evapotranspiration). In the heat of the summer, that could mean once a week for trees, 3-5 days for shrubs, and daily for perennials. In the winter, that could mean 14-21 days for trees, 7-14 days for shrubs, and 2-4 days for perennials. This adjustment is exactly what Rachio does on the Flex Daily scheduling, and assuming that you can get your system settings dialed in and you have a good functioning system, it works wonderfully.

Keep in mind, that page was designed for a desert climate like Arizona, but the basic concepts for watering needs would be the same regardless of where you are.

I hope that makes sense to you. A little more explanation on my math…

Your perennials need .5 gallons each watering need, which depending on climate, could mean 2-3 times a week. Assuming we would normally water trees once a week in the summer months, we need to break that out into 2 or 3 waterings, so 10pgh emitters would put down 20-30 gallons a week, which is enough for a small to mid sized tree. Shrubs we can assume need to water 1-2 times a week in the summer, and we want to put down 4-8 gallons for a mid-full size shrub.

It isn’t perfect math, but neither is the configuration of your system, but I think this would put you in a much better place than your current 1, 2, and 4gph setup.

It makes complete sense actually. All of my tress are super small - less than a few years old. The challenge here will be which settings to use in the advanced config to get somewhat these numbers/frequency.

Are you wanting to try a Flex schedule, or are you fine with a fixed schedule with weather intelligence?

Yes, and this is exactly the crack of the matter… or actually of my confusion. Let’s say for perennials I want to deliver .5 gal per watering. Rachio can keep track of soil moisture and figure out how often to resupply water, but I can’t just tell it “apply .5 gal when soil moisture drops below 50% AD and you run this zone with 4 gph emitters”. The only option I have is to feed it inches-per-hour. Now, for all intents and purposes, drip spot emitters have no area (like points in geometry). So how do I convert GPM to IPH for something that has no area coverage (or if there is area coverage it’s so small relatively to the area being watered then the efficiency would be quite close to 0 – i.e. an emitter delivering water into 1"-2" diameter area vs the tree’s canopy area)?

Oh good point. I think a fixed probably would be best in this scenario as no algorithm for flex daily could possibly work well here.

your scenario is is not unusual builders and landscaper do the same . your drip irrigation will plug up depending on the water type. we have potable irrigation here and they don’t filter it enough, so the irrigation plugs up. its best to use a fixed schedule. Set up difference schedules so you can active a trouble zone. worst scenario you can always add more zones. with good water pressure, you can have 21 to 24 gals dissepiment per zone, so count the heads. Exp 4 rotor head with a 3 gpm head is 12 gals per min dissepiment. Spring heads very .5 to 3 gals depends on style. I added 10 min manual cycle and soak time too not the best. need to have to it each zone. that will let the ground soak up I run my drip irrigation for 15 min no more, my Lawn back yard strip 15 min and large yard areas for 50 min- all zones every 3 days. late evening hours. Disregard those that say you should not water at night, God waters at night!.