When using a spade... the first 2" is 'ok' to penetrate, below that it becomes a chore. Texture is crumbly, brittle...below that is breaks off in large clumps.
Moss grows very well in winter.
I do not irrigate in summer. I haven't had the change to install a sprinkler system. Grass, for the most part, dies. Except in shade. (We have little-to-zero rain from July to mid-Sept. Usually.)