Thank you Major.
The base material is made up of mostly natural stuff mixed with liquid limestone acrylic sealer.
Earth, sand, tea, coffee , leaves, crayons, colour pencils ,cork etc. I found a cheap coffee grinder from Lidl that is great for grinding. Even grinds 3d printed resin supports which is super for rubble (Note i grind outside because most dust is harmful ).
Sometimes I add drops of concentrated grout colour to get different shades. I also thin white acrylic wood paste with the sealer to a sludge.Then fill old W&n plastic colour bottles with the stuff. I put a sample of it on the cap as an indicator. Scrape it off when a new batch is made. Small pieces of dried paint can be ground also.
I have around 10 different shades of green & brown, plus bright colours for alien terrain. There are loads of pics on my blog.
The plants are all hand made from dried asparagus fern leaves.Coloured according to need.
Doing camo on 15/18 mm is not easy ( doesn't look perfect under the camera ) but looks good on the table top. Paint & thin permanent markers were used to do it.
Z