Clay soil, default root depth is 6". Had a real bad thatch issue in my yard, and pulled a few soil plugs up and saw the roots were only maybe 2 inch deep. Did a deep dethatch, last week. Been using Flex Daily for the last 2 years, wondering if I should keep the 6" root depth, or change it to say 4"? What would be the consequence of this? More frequent watering?
Also, most users on here going out to all their zones, and and pulling up plugs of soil to see their depth throughout their lawns??
Unless it’s a new lawn, or if you are seriously limited for water in the short term, I like to water to where I want the roots to be. For example, I have Warm Season Grass which Rachio lists as 9.84" root depth (no doubt a conversion from 25 cm root depth), but I have Centipede grass, which sources I’ve found online call for a root depth of 6", so that’s what I use.
Changing Root Depth has the same effect that changing Allowed Depletion: Reducing it will water more often with less water, Increasing it will water less often with more water. Either way, the amount of water applied over time will be the same (Crop Coefficient will change that).
I doubt most are pulling plugs from the soil to check for roots. Some roots are finer than hairs and are difficult to see. I’d just go with the published value for your grass.
The reason I ask is, with Cool Season lawn here, there is NO WAY that is 6 inch root depth which is what I have had my flex daily set to the last 2 years (pic taken prior to me detaching my lawn last weekend, you can see how frail the grass looks too due to not much watering.) 3 year old lawn
Not sure of the exact depth of the plug (guessing about 2"), but there are definitely fine roots at the very bottom of the plug. I think they go deeper than you think.
And if the grass is frail due to not enough water, then that would mean the roots are not deep enough, and need more water to go deeper.
So besides changing nozzle inch’s per hour (did a catch up test on all zones), what setting do I change to get more water to get roots deeper?
A proper soil setting, root depth and Allowed Depletion pretty much determine root depth. Assuming your grass is capable of putting roots that deep, those settings should keep your soil moist enough. That assumes your soil from 3" to 6" (with a 6" root setting) stays pretty moist. Which will occur after a lot of rain, or you can water extra by Emptying a zone to help fill it. After that one time, a properly balanced system will let the first 3" dry out, keeping moisture below that and enticing the roots to grow deeper, then water and fill the first 3".
Those settings all look fine to me. The only unknown might be the Nozzle Inches per Hour, although that’s a decent average figure. If you could do a catch cup test, or measure water flow and area, for your zones would be my only suggested fine-tuning.
Somewhat off-topic… what soil sampler do you have?
I’ve been wanting to buy one, but Amazon reviews for anything below $100 are pretty bad (flimsy, easily bent, etc). And paying more than $100 is not in the budget at the moment.
I don’t have a soil sampler. I do have a moisture meter, medium quality, but it really doesn’t tell much.
oh, i’m sorry, it didn’t come off clear. I was asking @gizbug since there is one in the posted image.
Rittenhouse Soil Sampler Probe https://www.amazon.com/dp/B0002X4JWU?ref=ppx_pop_mob_ap_share
Isn’t the idea to get the grass roots to seek the deeper water?
In terms of the sampler, $49 really? That’s seems a bit overpriced. That should cost no more than $10 bucks.
Make sure you know the texture of your soil. If what you enter is not correct, the Rachio will irrigate incorrectly and you will have poor results.
The tool is called a soil probe and can be purchased online at Gemplers.com. I get the one with the foot “rest” to help push it into hard soil. The narrower ones are easier to insert.
