What to adjust when overwatering is suspected

I suspect I might be over watering a bit based on the presence of mushrooms. Lots of them. The yard looks very healthy otherwise.
I have dialed in my advanced settings and I am pretty confident in them. The loamy sand soil I have seems to push rachio to want to water nearly every day.
I have a good idea of what effects certain adjustments will have but what should be the first thing to tinker with in my situation? allowed depletion, crop coefficient and/or available water seem to be the most subjective. The others are easily measured so I would hate to fudge those numbers to something inaccurate.
Maybe I am overthinking it and the presence of mushrooms is fine?

I’ve had mushrooms in my yard, but usually only after an extended wet spell, never by irrigation.

Have you been operating your Rachio for quite a while? And is this the first hint you’ve gotten that might indicate over-watering?

Nevertheless, if you want to reduce the amount of water applied per week (over time), and are pretty sure of your other factors, try reducing the Crop Coefficient a bit. Maybe 10%. Problem is, with sandy soil, you can’t apply as much water at one time, so may be stuck with watering almost every day in hot weather.

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Do you have any trees around that area? I always have mushrooms in the Spring that grow near my Sycamore. Some trees healthy or not seem to link with fungus. I did some testing the past few years with different watering and the mushrooms still grow during Spring. I’ve concluded its something to do with the spring growing cycle of the Sycamore. I’m guessing some other types of trees have similar characteristics. For you if not something like that then it probably is due to overwatering but might depend on the type of mushroom as well. Fungus is interesting.

Root depth is another parameter to check. If the setting isn’t deep enough, as I understand, Rachio will water more frequently, which would keep the top layer of soil from drying.

Root depth should be set as measured though right? I know default for cool season is 6” but I changed mine to 4.5” after doing actual measurements.

Root depth should be set at where you want roots to be, not where they currently are. You want to encourage roots to grow deeper by forcing them to seek water at lower depths. If there is readily available water at a shallower depth, they have little reason to go deeper.

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Makes sense I guess. Does the moisture level in soil actually empty from top down like that though? Even with sandy soil? Seems
Like the moisture would deplete equally throughout the root zone

Higher layers of soil will generally be drier than lower because of gravity and the sun, so the content of water in soil is a function of depth (that’s if you simplify the model and ignore a myriad of other factors, like layering). Soil type does affect how much difference there is between the top and the bottom and how fast that difference changes. However, I think Rachio assumes uniform distribution of water in its calculations rather than trying to apply calculus :slight_smile:.

Still, going back to the original question, if you see mushrooms, most likely that’s because you have too much water in the thatch layer and that is because it’s not being given a chance to dry out between watering. Since your root depth is on the short side, I’d rather start with reducing the frequency of watering than reducing the amount of water.

Another reason, I just realized, could be that you are running sprinklers too early in the night. The lawn staying wet through the night could end up with fungus growth.

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Thank you for your tips. I do have a thatch layer bordering on too much so that makes sense. So you say increase root depth? That will increase watering time and decrease frequency right? Why not just leave that alone and increase allowed depletion?
I have my schedule end before sunrise one entire watering is about 2 hours long for all
Zones. Maybe I should change to end by 9 am or something?

While both may have the same effect, Root Depth should be increased to the recommended value for your grass, so I’d go that way.
I have my schedule end before sunrise one entire watering is about 2 hours long for all
Zones. Maybe I should change to end by 9 am or something?
The more watering before sunrise is done, the higher chance of fungus, and after all, mushrooms are a fungus, right? (Maybe?). I have my system start at 5 AM, and while it usually waters only a couple hours, depending on zones needing water, it always stops by about 11 AM, and that’s good with me.

I have cool season grass and Raccio defaulted to 5.9 inches should I change it to 6 inches? I know it’s not much of a difference but I do want to try and establish deep roots.

You won’t see, nor will your grass feel, a difference of 5.9" or 6". It appears to me that many of Rachio’s recommended depths were originally chosen using rounded metric dimensions (15 cm is 5.91", and the 15.75" recommendation for shrubs is 40 cm), so sometimes come out to what appear to be extraordinarily accurate inch dimensions.