The first question to ask yourself is this, do you need to grow something? If yes you will want to consider a soil that contains organics. If not you can get by with a subsoil, or fill soil. The diagram below demonstrates the soil hierarchy, with topsoil on top, followed by subsoil beneath it.
Our topsoil, compost and eco soil all contain organic matter. They are similar in makeup but their uses differ. Topsoil is a finely screened organic soil. Topsoil contains 30% compost, giving it a dark, rich look. Topsoil is a preferred growing medium for most plants, and of course, grass. Compost is also finely screened and is well suited for growing plants, and vegetables. It’s made up of mainly decomposed leaves. It’s dark in color and highly organic. It is known to grow enormous vegetables, and even champion pumpkins. Eco soil is similar to topsoil, the only difference is that it is not as finely screened. Eco soil contains more small sticks (2″ and less) and more small stone (3/4″ and less). This material is preferred for berms, and the planting of trees/shrubs.
Now if we are not growing anything, or need to fill in an area before we are able to plant, we can use a subsoil. Subsoil, or fill, as it is commonly referred to, is cheaper than topsoil. It lacks organic matter and is usually a tan or brown color. It can be screened or unscreened, and the use of the material will dictate which will be needed. A common hole in the yard, such as an old swimming pool, would only require unscreened, or “clean fill.” Clean fill would be sufficient because a pool is such a deep void (often around 6 feet deep), the stone and other debris won’t be of concern. Now screened fill can be used the same way that unscreened fill is, with the added benefit that it does not contain rock, or debris larger than 3/4″. This is ideal for a homeowner who will be moving it with a wheel barrel, because rock free material is much easier to shovel than material that can contain rocks (clean or unscreened fill, can contain rocks the size of basketballs).
Another common scenario is the need to fill an area, and top dress it with topsoil. The picture above shows the outline of what previously was a swimming pool. By buying clean fill for $12 per yard, we would of saved a substantial amount of money compared to filling the same area with topsoil for $29.00 per yard. Topsoil is still used, however only for the surface layer.