What in the soil makes plants grow?

The organic matter in soil comprises living things and their remains. The inorganic matter comprises minerals and rock particles. Humus, or decaying organic matter, allows more air and water to enter the soil. Dead organic matter also provides fodder for plants. Earthworms improve the soil by turning it over. Plants get nitrogen, phosphorus, potassium, calcium, iron, sulphur and magnesium from the soil.