Often also referred to as “substrate” or “potting soil”, growing medium is a material, other than soil on the spot, in which plants are grown.
Growing media are used by the horticulture industry as well as consumers to support the development of plants. The growing medium ensures that the plant can healthily grow by providing it with a range of essential elements:
• An optimum rooting environment for physical stability
• Storage of air for the roots
• Water absorption and retention –> availability to the plant when needed
• Supply of nutrients for the roots
Growing media are used to grow a wide variety of plants including vegetables, fruits, floriculture ornamentals, tree and shrub ornamentals and speciality plants.
The range of growing media constituents used includes peat, coir pith, woodfibers, bark, composted materials i.e. green waste, and bark. Mineral constituents like perlite, pumice, clay and vermiculite are also used. Growing media are often formulated from a blend of such raw materials, usually enriched with fertilizers, lime and sometimes biological additives in order to achieve the correct balance of physical, chemical and biological properties for the plants to be grown. Having the right growing media mix is as important for an optimal plant growth as water and fertilisers.
Plant species differ considerably in their need for water and nutrients, and therefore need different kinds of growing media to provide the best growing conditions. Due to this, a wide range of different kinds of growing media are available on the market. The horticulture industry uses thousands of different growing media mixes.
In this context, the growing media industry chooses different materials based on their performance, the plants’ needs, availability and sustainable development considerations.
• For young trees and shrubs a substrate with wood fibres or bark is often used as it provides more physical stability
• Clay is frequently used for plants with high water needs as it can store the water longer
• Perlite is a material used to enhance the drainage of water
In sum, the right growing medium provides growing conditions that are predictable and reliable for the grower, contributing to higher yields and more efficient growing