Have anyone use sand from sand dunes as substrate for planted tank? The grain is really fine and heavy; it sink immediately when poured into the tank so it does not 'foul' the water.

I have thrown some crypt with the cotton and lead weight directly in the tank without planting the root into the sand, will the crypt survive? Reason I did not plant the root into the sand is because I am afraid that the sand may be too fine and compact thus nutrient will not be able to get to it. Will the roots rot if it is not planted in the sand?

I am trying to keep hairgrass and crypt in it, any suggestion or comments are welcome.