Water as a limiting factor in performance

[Adam_M]

I re-seeded a portion of my lawn, (with fescue, it's a steep hill) next to an area that has perennially underperformed and that I've lost either partially or completely more than once. This year, with the help of Morph, Andy, and others, my losses were low-ish and self-inflicted (note to self: applying sedgehammer in a "cold" spell in the summer, trying to skirt max temperature recommendations, still stresses the grass out. A lot.)

I've noticed the area that got water overspray from the re-seed did and continues to perform markedly better than the area directly adjacent which I did irrigate, but with 1" of water (which I did calibrate- with this sprinkler it was almost 4 hours) once a week. The frequent and shallow irrigated area looks like my best plots - full, lush, dark green, where the adjacent area looks semi-dormant with spotty areas of dead grass and much less vigor and worse color.

That leads me to believe water is the limiting resource, but I'm not quite sure what it tells me as far as a plan of action. The soil is heavy clay, so I don't expect it's just running through the root zone, and I don't see it streaming off either. This area gets full sun. All day. It is also a mild/moderate slope, perhaps 1:20 or so facing southeast. Can those with more wisdom provide advice?

Thanks!

[MorpheusPA]

Yes, water's your limiter, but your grass won't reward you with daily watering (you'll end up with short roots and a lawn that's susceptible to diseases). If you find that weekly watering isn't doing it, shorten the cycle. Maybe every 5 days? And step back the amount accordingly, to about 5/7ths of an inch or so (0.7 inch). In very hot weather, you may even need twice a week and a full inch.

Southern-facing areas (one of mine faces southwest, which is horrible) do tend to be drier and will require more watering, so that's reasonable. Let the grass tell you; when it wilts, and doesn't recover, it really needs water.

[Jackson]

What is your height of cut?

[Adam_M]

3.75", but we're on the way down for winter. It'll end up between 2.5" and 3" depending on how long I keep interest in mowing this fall.