If you mean sucrose, then children have been conducting an analogous experiment since the 1940's at least. A supersaturated solution of sucrose in water will grow rock candy crystals on a string or a stick. I did once try to grow a very large perfect sucrose crystal by suspending it on a supersaturated sucrose solution suspended in gelatin. But it cracked after getting less than 3/4" in size.
Making a supersaturated solution of sucrose in water isn't easy. By volume, it ends up requiring 3 times the mass of sucrose to water -- i.e. for the kids, 3 or 4 cups of sugar to one cup of water. My gelatin experiment was even worse, I needed way more of both sugar to make a supersaturated solution, and more gelatin than normal to gel the solution.
What, exactly, is your application? As I understand it, these days, as long as the crystal is quite pure, it can be pretty small and still be useful for x-ray crystallography, and the like.