Which of the following is NOT an artificial growing medium?

Soil is considered a natural growing medium because it is a complex mixture of organic matter, minerals, gases, liquids, and organisms that support plant life. It forms through a natural process over time and includes various components such as sand, silt, clay, and organic materials. In contrast, artificial growing mediums are typically manufactured and engineered substrates that provide specific physical and chemical properties conducive to plant growth.

Peat moss, sawdust, and gravel, on the other hand, are all materials that can be processed or altered for use in horticulture and agriculture, often mixed with other components to optimize growth conditions for plants. Peat moss is harvested from decomposed plant material in wetland areas; sawdust is a byproduct of wood processing; and gravel is mined and used to create well-draining environments for roots.

Understanding the differences between natural and artificial growing mediums is crucial for effective plant cultivation practices.