Hydrawise Triggers?

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Hammbone81
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Hydrawise Triggers?

Post by Hammbone81 » May 9th, 2021, 7:46 am

My new irrigation system (first time irrigation owner here) had a Hunter Hydrawise Pro-C controller. Its awesome.
I'm looking for advice on the best approach for setting up watering triggers.

A couple points of interest.
1) I live in Iowa about 8mi north of I-80.
2) I was not blessed with "good Iowa soil", we live near a river and the top soil was removed so our soil is very sandy.

I'm still experimenting with 3x vs 2x per week. We really haven't had enough heat stress to really know yet.

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MorpheusPA
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Re: Hydrawise Triggers?

Post by MorpheusPA » May 9th, 2021, 8:41 pm

For those of us without the system, edumacate us regarding what the triggers could be? Visual triggers are best for determining when to water the lawn, but they do correspond to actual physical correspondence in the soil.

For the most part, experience will tell you when that is, and it's strongly weather-dependent. In spring, 2x a week would be most unusual (once a week watering is most likely even in very sandy soil). Fall, ditto. Summer...varies.

Visually, bluegrasses will turn a grayish tone and wilt a bit in sunlight when they run out of water. That's the point where water is absolutely required (it would have been best to water the day before to avoid drought stress if that's your goal; I don't personally irrigate, so...) At that point, the soil is dry to the base of the feeder roots, about 4" deep in thicker soils, 6" or more in sandier ones.

That's the best visual cue. It can take 2 to 3 days in almost pure sand and very hot weather. It can still be a week in less sandy soil or cooler weather.

Hammbone81
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Re: Hydrawise Triggers?

Post by Hammbone81 » May 9th, 2021, 10:10 pm

Morph,
Trigger options are as follows:
(I'll put the user adjustable variables in parentheses)

1) Don't water when today's forecast is less than (60)°F
2) Water (30)% less when today's forecast temperature is less than (68)°F
3) Water (30%) more when today's forecast temperature is greater that (86)°F
4) Don't water when the chance of rain is greater that (80)%
5) Don't water when today's forecast wind speed is greater than (19)mph
6) Don't water when the last 24hr rainfall is higher than (0.2) in
7) Don't water when the last (3) days rainfall is higher than (0.5) in.

The controller has a rain sensor connected. It just knows if it's raining or not, but not how much. For everything else, it syncs up with weather underground references the nearest weather stations for data inputs.
For the (variables) I entered the pre-canned values. I may have adjusted that last one.

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MorpheusPA
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Re: Hydrawise Triggers?

Post by MorpheusPA » May 10th, 2021, 4:17 am

So nothing easy. Certainly never water when the last three days rainfall was greater than 0.7 inches, I'd say.

But honestly...I think I'd set the system off manually when watering needs to be done, for a determined amount of time known to deliver the set amount of water needed to wet the soil to below the deepest root system of the grass (for a very sandy soil, usually about half an inch of water). That's actually what I do with the gardens (in my case, for deeper rooted plants, mostly rather drought-tolerant, watered perhaps every seven days to keep flower production at maximum levels even in the worst weather...with an inch and a half of water on mulched soil).

For grass, that's going to vary by temperature. So at temperatures under seventy, probably no water required unless you're in a drought. 70-80, watering zero to once a week depending on rainfall. 80-90, probably once or twice a week depending on rainfall. 90 or so, twice a week unless you're getting good storms. 90-95, twice certainly without rainfall and maybe even with it.

Hammbone81
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Re: Hydrawise Triggers?

Post by Hammbone81 » May 10th, 2021, 9:01 am

MorpheusPA wrote:
May 10th, 2021, 4:17 am
So nothing easy....
Well, yes, there is an easy option. I could just do time based watering.
All of those triggers are for the "Virtual Solar Sync" setting that tries to account for air temp, wind speed, etc.

I've watered a few times this spring because we have been having drought conditions. Last weekend (9 days ago) we had two days of mid-high 80's and WIND! People's lawns dried out SUPER quick. I had watered in advance seeing it was coming and it saved my hide!

Temps a cooler now, and we got 1.4" rain two night ago. I'm going to just hang tight with watering for a while until I see signs. (I know what they are, been there way too many times, hence the irrigation system).


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MorpheusPA
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Re: Hydrawise Triggers?

Post by MorpheusPA » May 10th, 2021, 8:55 pm

I mean nothing like, "Water when the soil sensor attached registers completely dry." :-) Or a given resistance set that happens to correspond to just before the wilt point of the grass. Now that? That would be easy. Particularly if you could water up to a given resistance on said soil sensor.

Yeah, my own lawn hit the wilt point last Thursday, just before an extended rainfall. I was studiously ignoring it.

Timed watering isn't bad. Set said time to deliver (in very sandy soil) about half an inch of water as measured in a tuna can. Do that whenever the grass starts to wilt across whatever percentage of any zone wilts depending on how sensitive you are to bad-looking grass (my sensitivity is near-zero and bluegrass will happily go dormant once well-established, so I let it do that).

Hammbone81
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Re: Hydrawise Triggers?

Post by Hammbone81 » May 11th, 2021, 7:50 am

Actually, they make said soil moisture sensor, and I really wanted it. The project manager/ system designer talked me out of it. He said they're great in theory, but not in application. In an ideal world they'd be in undisturbed virgin soil. But the act of installing them disrupts the soil then that spot is no longer like the rest of the lawn. Expansion and contraction takes place, then an air gap forms around the sensor and it stops making contact and therefore stops measuring moisture content.

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MorpheusPA
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Re: Hydrawise Triggers?

Post by MorpheusPA » May 11th, 2021, 4:50 pm

Yep, that's always the problem. You'd have to keep reseating the sensor every year in spring, which really wouldn't be too much of an issue. It's the same reason my landscape lights work themselves out of the ground every winter; freeze-thaw around the metal creates an air gap several times a day and the lights pop out of the ground by spring. Reseat in early April and they're fine until the following February.

Then I'd just do it visually and let the wilt point be your guide. When it starts to wilt in a zone...water. And you can tell it's wilting by the color change to green-gray. This might be mildly problematic if you're color blind or have a poor sense of color, but even then, the grass actually does become darker as well.

How far you let it go is up to you. At a few percent, the soil is probably pretty dry but there's no major stress. At half, that grass is stressed. At fully wilted across the whole zone, dormancy is probably about to begin in the worst of it. Overstressing the lawn is, perhaps, not the best idea.

I actually don't allow the flower gardens to stress much at all for optimal performance, so if I see wilting that can't be easily explained ("it's 100 degrees out at noon on July 10th, the soil is damp, it's just that the root systems can't keep up right now"), I water. And sometimes the grass does that too; wilting during the day will reverse at night if the day is very, very hot and the roots just can't keep up. So a little grass whispering is in order at times as well...but you'll usually know that.

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Re: Hydrawise Triggers?

Post by ENVY23 » July 31st, 2021, 3:41 pm

Did you get this dialed in? Any feedback? We just moved and I’m getting a system installed next week and I went with the Hydrawise. I really wanted the Sprinkl controller with wireless soil moisture sensors to make everything fully autonomous, but I emailed them and they’re releasing a new model that won’t be here until summer 2022, and the current model is sold out. So I’ve been trying to learn about the Hydrawise. Most YouTube videos seem contractor focused, and I’m looking for more end-user information.

From what I can tell, Time Based and Smart Watering both use the weather stations(Weather Underground) to determine how/when to water, but the difference is Time Based will water with the same frequency(i.e. every Friday) but change the duration to water longer or shorter depending on weather. On the other hand, Smart Watering will water the same duration(i.e. putting down 1”), but will water more or less frequently based on weather. It seems Smart Watering is the one we would want? I would appreciate any other tips or advice you could share regarding your experience with the Hydrawise. Thanks!

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