So I like this Idea. I decided to try it. My reasoning:
1) Sugar sand is freaky cheep
2) Sugar sand does not drain well
I hear you! "Wait don't you want good drainage?" I shall elaborate.
The sand forms the center of the mass. I pile up wet (wet!) wood and I use saturated (or nearly saturated) sand. This is the core.
On top goes 3 to 6 inches of topsoil.
I figure. The wood acts as a wet sponge which breaks down to OM. Awesome. The saturated non draining sand? That's a huge water bank. The roots branch out in the top 4 of topsoil and get all the food stuff they need and that tap root starts working its way down through the wet sand which should be very slow to evaporate, especially since the wood is conducting moisture up through the ground.
sugar sand is just about pure silica, in fact it is the preferred sand for making glass. Let us know how this experiment works out, seems to me that it should do well enough. If you really wanted to get experimental you could mix compost in in one half of the mound and leave the other half pure, then plant the same plants on both halves and keep records of the grow season. That would let you know just how well the pure idea works.
There was plenty of compost and other stuff and mixing too. I will certainly keep in touch about the project though, especially as it pertains to water retention and availability. Thanks for the interest.
Hau, Landon, yes I am very interested in this project. There are lots of areas along the south east coast with this type of sand, so far the best plants that grow in it naturally are sea oats. I am thinking your project could end up being of interest to anyone wanting to set up gardens on the Florida coast line. I know of a few state parks that have tried to put in vegetable garden areas only to have them collapse after a couple of years and be abandoned by the service. Your project could go far and influence many.