Neither the builder nor the farmer builds or plants on sand.
Whatever your build on sand will sink or shrink.
I remember those 'houses' we used sand to mould on our fists as children...many of them crumbled just as soon as we withdrew our palm.
Whatever you plant on sand will wash away.
Sand takes in water fast but cannot retain it for long because it is porous.
Everybody is building. The question is where?
If it does not last, check where it starts.
If you want it to stand, don't build on sand.