Originally Posted by BostonBull
roots elsewhere are 6" or so.
I mow 2.5-3". Small lawn, but yes due to trees and fence the areas with the moist CG, also get the most sun.
So, where the roots are deeper, the grass is obviously healthier (probably thicker and taller as it is better nourished/water uptake) and where the roots are more shallow, the grass isn't as healthy, less capable of choking out the weeds, particularly the crabgrass.
Makes sense, it is why I grow/mow my grass tall and do everything I can to encourage deep root growth (increasing my OM, using Myco coated seed the last time I overseeded, using TTTF seed, etc.) and keep the grass as thick as possible.