u/Puzzleheaded_Arm_719

Hello. Installed new sod as part of a whole house remodel. Did well for about 4-6 weeks and is now struggling in quite a few spots. Irrigation seems to be pretty even but I’m reconfirming now by heavily spot watering. Google says it’s root rot, but when I dig down a bit nothing seems soggy or hardly moist. Lastly, I don’t see insects.

Any help is appreciated on steps to diagnose and then treat. Could some very alkaline soil in spots due to digging be to blame?

Thanks!