I'm planning to put in some cacti under the eaves of my house where it rarely gets wet. It's meant to be low-maintenance. Total area will be a little less than five sq.m. One concern is to make the place unwelcoming for termites, with maybe ants as a secondary consideration. We have a service spray every three months and have insecticide tubes under the house already, but I don't want to have a hidden problem under the surface either. The house is concrete and steel construction. The soil that I will add will raise the level there about 40 cm above the bare hard dirt which is there now. Would it be prudent to line the area with something to discourage termites? Plastic sheeting would retain moisture when we do actually water or rain blows in that direction. Maybe some kind of fine mesh or screen?

 

I would appreciate knowledgeable answers about what soils to use, other than the (mostly decorative) layer of gravel on the surface.

Switch to the Sentricon system for eliminating/preventing termites.  Much more effective than insecticide.  (Insecticide only kills termites it comes in contact with.  Sentricon makes any colony sterile so it dies out completely.)  Plus no dangerous insecticides.