Soil can be found when excavating at excavation hotspots and material caches while training Archaeology. Material caches will only yield soil if they are located within a dig site. There are six different types of soil, one of which is only used during the tutorial. Each dig site yields a unique type of soil that can be used at the screening station in the Varrock Dig Site for a chance at uncovering Archaeology materials and artefacts, though the latter is rare. Up to 100 of any one type of soil may be screened at a time. Alternatively the auto-screener v1.080 may be used to screen soil as it is excavated, however using this method will never yield additional artefacts.
Combining one each of all five of the tradeable soil types with a cup of tea will produce a cup of soil tea, which temporarily boosts Archaeology by +2 levels. This effect does not stack, nor does it appear on the buff bar.