Lawn and all plants are severely stressed! How do I increase FD output?

Hi - I live in Arizona (If you couldn’t guess by my forum ID!)

My yard and all my plants are getting yellow. How do I increase the total water output to my yard in Flex Daily? When I read about the Flex Daily adjustments, it seemed that changing just about any setting would increase the water amount AND reduce the frequency (or, vise-versa).

I’m looking for more total water going into my yard for the next few months.

Is there a single FD setting I can adjust to increase my total water output by about 25% (to start)?

Thanks,

AzJazz

Couple thoughts here. You could switch to a fixed schedule - you get exactly what you need.

Or you manually mark the zone as empty, thus forcing the flex daily schedule to water the zone.

(Go to the zone, click on soil moisture, empty)

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If you just want to put 25% more water but keep the frequency of watering the same, you can adjust the sprinkler precipitation rate. So multiply your current precipitation rate by 0.75 (1-0.25) and plug it in.

This may produce the desired result, but is mathematically incorrect. If the precipitation rate is reduced to 0.75 of current, the run time will increase to (1 / 0.75) = ~1.33 times the current value.

In another example, if you cut the precipitation rate in half (reduce by 50%), the run time will double (increase by 100%).

You are right. You then need to divide your current precipitation rate by 1.25, to increase watering time by 25%.

Thanks, guys! Where do I enter the precipitation rate adjustment?

I searched through my settings, and I couldn’t find it.

AzJazz

Precip Rate is also known as Nozzle Inches Per Hour in Advanced settings.

It’s actually called “Nozzle Inches per Hour”, and it’s the last value in the Advanced settings for each zone. Personally, I wouldn’t start there in your case though. To IMMEDIATELY change the amount of water applied per week, which is what you want to do, increase the Crop Coefficient (also in Advanced settings), maybe by 10% at first. That solely determines the water applied per week. I’ve put information about this in a new forum thread on the “Getting Started” forum, you might want to look at.

To do it right, though, try to determine an accurate value for Nozzle Inches per Hour by doing a Catch Cup test (described on this site and elsewhere); you really should measure it to do things right, and make it easier on yourself later.

I have a clarifying question here. When you say change by 10% are you saying take your initial value and multiply by 0.90 or 1.10? Or do you mean literally go from 80% to either 70% or 90%?

I was talking about the Crop Coefficient, but it applies to either really. In your example, changing from 80% to 70% or 90% involves only a 12.5% change, so there’s not that much difference. I was just saying that you normally would change the amounts in relatively small increments, on the order of 10%. If your yard and plants are stressed as you say, you might want to go more, though. Better to overwater a bit, then cut back, than make it worse on them.

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Thanks, @rraisley -

I did a catch cup test previously a year or two ago, and I thought I already adjusted my grass sprinklers to correct. I must have adjusted something else, because my nozzle inches per hour for the three zones is currently set to 0.9. I know that I had very different rates of water for each zone, so I’m pretty sure I had a different setting per zone. Maybe I adjusted the wrong value previously.

I still have the catch cups, I guess I should go through it again.

First, I’ll check out your thread in the Getting Started forum.

AzJazz

Make sure your weather station is giving you good data. Rachio doesn’t check to see if it’s working properly. Is your Water loss as reported by Rachio reasonable?

Hi, @rraisley - I temporarily increased the crop coefficient on all my zones by 15%. I looked at my run times, and it doesn’t look like any of them have increased in length (for example, my grass run times stayed at the same 36 minutes in each zone after the update).

I don’t think changing the crop coefficient had the desired effect.

Increasing crop coefficient will increase the ET daily loss, and has no effect on watering amount. Instead it increases the frequency of watering.

This is a helpful link that explains impact of different settings on runtime and frequency:

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Thanks, @moisture!

I had the same issue in so cal. Crop coefficient isn’t really described anywhere in the help very well, but it is probably the most important setting for being able to add more or less water. The sun setting being another but I’m sure you have those on full sun. You can understate the nozzle rate but it nice to be able to have a more accurate gallons used. As you noted, most of the other settings trade frequency for duration.

moisture is correct. Increasing Crop Coefficient only increases the ET loss, which increases how much water is applied over time. But when using Flex Daily, it is the ONLY factor that will increase how much water your lawn will get per week (except for Nozzle Inches, which you lie to and tell it you’re getting less than you are, so it will apply more). Other factors only change how much water is applied at one time.

With Flex Daily, there are only 2 resultant numbers for each zone: The total water applied per week, and the maximum total water applied at one time.

Total per week is determined by the temperature/humidity/etc. (i.e. the weather, and it varies) and Crop Coefficient. Since we can’t control the weather, it’s best to control the Crop Coefficient.

The total water applied at one time is determined by the soil’s Available Water, the grass’s Root Depth, and the Allowable Depletion. Other factors don’t affect it.