When you uproot a grass clump like that, you break off the deep roots. They are very fine.
It takes a few years for them to root that deep, but yes, they will root upwards of 4’.

We excavated into this hill to rebuild a retaining wall last year. This was around 30” deep. You could follow the fine roots from the grass still going down past the excavation point. 4’ or more wouldn’t surprise me. Next time I dig that deep, I’ll try and get better pictures.

 

The issue is shade....tall fescue needs sun and if it gets more than 30% of shade during daylight ours, will not grow properly.

Then the roots get finer as they go deeper.

When you have shallow roots like that, its for being watered too often and the plants has no need to expend energy seeking out moisture....why should it if it's always shady?

 

I just see a thing the other day where they said Fescue roots can go 3 ft deep

 

it's all about soil prep. On the projects where I can go in and rip everything 18-24" deep or simply fill it's night and day for turf vs the contractor special most people do where they are running a harley rake across hard pan soil and throwing down seed/straw or sod.

 

Agreed. Soil is key. We have red clay here. Nothing goes through the clay. New construction is stripped and filled with 2-3” after it’s built. Without adding soil, those lawns are hard to keep nice.

 

🤔

 

The expert has spoken........

 

I seen testimony that in perfect conditions TTTF can root up to 3 feet. Perfect conditions I assume is loose loam or even something like potting soil, but it likely should get its minimal weekly deep watering. However, I know of many fescue/blend (bentgrass from birds/seed blends, even hard [fine[ fesce] etc) lawns that are very much on the dense clay side and are never watered (except likely when established many years ago) and the roots are only a few inches due to the dense soil but this clay holds moisture so well that the lawn never burns out granted it's not cut too short before drought. So it really depends on the soil type, sometimes clay is actually good. Whereas most others with more sandy loam can fry out in full sun.