Yes, I would like to try that method as well, the problem here is finding the correct sand....the only sand for sale here is very compact cement like building sand, or decorative sand which of a consistency which makes it very poor for growing plants (when it gets wet, and then dries, it solidifies to a hard crust!)
it seems that the sand in the log looks a bit like the very porous granitic sand found in Sweden....
It is interesting to hear as well that the fritillarias enjoy the sand bed, as they can be hard here to keep alive, as they resent too high summer temperatures which makes them dry out, and too much water in winter/summer which make them rot...
Pontus