The "More on" approach to scenery

I've been struggling with a certain part of the ground cover in the St Thomas yard area.
I use Scenic Express Light Cinders for the yard tracks, and wanted to have a sense of that kind of material in surrounding areas of the yard. So I've been playing with tile grout as ground cover.

I've not had the kind of success with grout that others have.
If I soak it with enough water to start the portland cement setting, there's actually too much water and the mix never really hardens.
Soaking it and drizzling thin glue or matt medium results in a gloppy mess.
What I had tried with mixed success, was brushing very slightly thinned glue onto the surface and then sifting the grout onto the glue. The trouble starts when adding texture and colour to adjacent areas. The glue tends to leave marks that look like water marks in the grout. As well as the top of the grout is still loose and the dyes in the grout can be picked up easily with an errant finger.
So I wasn't in my happy place with this. The colours and marks I could address with airbrushing greys into the grout, but the looseness of the material wasn't cutting it.
On a whim and a suggestion from Trevor, I scattered some Scenic Express Fine Natural Soil over the grout and set it in place with thinned white glue.

I think this works!
Some of the grout dye was wicked into the dirt cover which helps keep some of the continuity of colour that I'm looking for. More importantly no more water marks and other unsightly stains, and everything is secured in place.
Further colour shifts can be made with the airbrush and military colours. But first more static grass and other vegetation has to go in before I make that determination.
Thanks for the suggestion Trevor! Don't think I'd have gotten there on my own.