hi, dolls house makers are everywhere and have a trick to replicate everything using locally available materials. For example, we have 2 grades of Milliput and a clay that sets called das for your purposes but, you may not. i believe you do have something called silver clay though that you set in a domestic oven. We use here tea, from used tea bags, dried and glued with pva, to represent soil around plat pots. So, though different kinds of model making has their own black arts, you may wish to frequent yourself with the dark world of the amateur dolls house afficianado. Incidentally, 1/12 and 1/20 scale are covered by these folk as a matter of course. Libraries and recreational sections of adult education centres often have lists of folk into different fields, while your most local dolls house magazine will have ads and other clues as to who is about. Good luck,
Luv n Lite,
Les Ballard