Renewable substrate raw materials with a workable structure and favourable water and air management properties
There are different types of coir products, including coir pith, coir chips/crush and coir fibre. These materials are obtained from the husk (mesocarp) of the coconut palm (Cocos nucifera). Coir pith is the fine fraction and can be used both as a pure growing medium and in substrate mixtures. Coir fibre consists of short-cut fibres that are mainly used to improve water distribution of substrates. Coir chips or crush are coarser fractions that provide additional air porosity in the substrate. After processing, coir products are chemically stable and suitable for use in professional substrates and consumer potting soils.
Coir products originate from countries where coconuts are cultivated on a large scale, including India, Sri Lanka, Côte d’Ivoire and the Dominican Republic.
Coir products naturally contain relatively high levels of salts and are therefore washed and buffered. The buffering process developed by RHP in 1996 prevents undesirable salts from being released during cultivation. Coir products are known for their favourable balance of water retention and air content and their fast rewetting. Coir pith has a relatively high air content, retains large amounts of water and is generally a homogeneous product. Coarser coir products, such as coir chips and coir crush, have a higher air content and improve drainage. To remain physically stable during use, coir pith must undergo a controlled coir ageing process.
Coir pith is used as a pure growing medium and as a component in potting soils and growing media mixtures. It is applied in vegetable, flower, potted plant and tree nursery production. Coarser coir products are added to provide substrates with a coarser, more open structure. Thanks to their fast rewetting, good water availability and stable structure, coir products are used in growing media worldwide.
RHP certified coir products must be processed to achieve a stable nutrient balance. By nature, these products contain excessive levels of potassium, sodium and chloride. In addition, requirements apply to the stability of the material. Risks such as viable (tropical) weed seeds, plant diseases and contamination with mineral particles are controlled throughout the entire chain and minimised as much as possible through process control. Compliance is verified by e.g. high-frequency weed seed testing.
