Sphagnum peat has a spongy, fibrous texture, a high water-holding capacity, and a low pH and nutrient content. Peat moss has been a choice material for incorporating into landscape beds for years. Muck peat is very different from sphagnum peat. Rice hulls . Rice hulls are a composted product that is increasingly available.
Rice hulls are quite stable, lasting up to ten years in the soil.
Sand is used in special sand mixes for golf course greens but is not a satisfactory landscape amendment. Sulfur, iron sulfate . These materials are used to decrease soil pH. Usually this is not necessary unless you wish to grow plants that prefer acid soil. Heavy clay soils require more sulfur than coarse-textured soils to enact a pH change. Heavy clay soils may require five times this amount or more.