This undisturbed soil is obtained from Vermont. It is silty, light colored, and poor in organic material. It does not have any artificial fertilizer or pesticide residues and can be stored indefinitely in a dry, dark environment.
Prior to its use in soil-water media, treat soil in batches by placing it in a heat-resistant pan lined with aluminum foil, fill the soil to a so depth of 4 cm, and bake at 120°C for 2 hours. After it cools, cover the pan with aluminum foil and store in darkness at room temperature. Avoid excessive moisture during storage.