Introduction

Coir, derived from the mesocarp tissue of the coconut (Cocos nucifera) fruit, has gained attention as a viable alternative to peat moss in hydroponic systems. This article examines the properties of coir and its potential applications in hydroponic cultivation.

Physical Characteristics

Coir dust, the fine fraction of coir, is a lightweight material with a bulk density of 0.04-0.08 g cm-3 (Evans et al., 1996). Its total porosity ranges between 86-94%, while its air-filled porosity is 9-14% (Lemaire et al., 1998). Coir fiber, the coarse fraction, has distinct characteristics, such as a total porosity of around 98% and an air-filled porosity of around 70% (Lemaire et al., 1998). Coir dust has a relatively high water-holding capacity of 35% (Prasad, 1997), resulting in superior growth of foliage plants compared to peat (Stamps & Evans, 1997). The high unsaturated hydraulic conductivity of coir leads to improved water availability and better yield of roses compared to UC mix (Raviv et al., 2001).

Chemical Characteristics

Crude coir contains high levels of sodium and chloride, which may harm plants. During the production process, coir must be washed, and calcium and magnesium are typically added to facilitate sodium removal and provide nutrients (Prasad, 1997). Coir is rich in phosphorus and potassium, which should be considered in fertilization programs. The cation exchange capacity ranges from 320 to 950 mmolc kg-1, and the carbon-to-nitrogen (C/N) ratio averages around 117 (Noguera et al., 2000; Evans et al., 1996). Nitrogen immobilization may occur in coir dust but not in coir-based media with conventional fertilization programs (Handreck, 1993b; Noguera et al., 2000).

Hydroponic Applications

Coir can serve as a standalone medium or as an ingredient in a mix for hydroponic cultivation of vegetables, cut flowers, potted plants, tree saplings, and young foliage plants (Meerow, 1994; Evans & Iles, 1997). Coir has shown growth results comparable to peat moss and is widely accepted as a peat substitute (Meerow, 1994; Evans & Iles, 1997). Furthermore, coir can serve as a rooting medium for cuttings under mist or in high humidity chambers (Lokesha et al., 1988).

Conclusion

Coir has several properties that make it a promising alternative to peat moss in hydroponic systems. With careful consideration of its physical and chemical properties, coir can be utilized as an effective growth medium for various plant species.

References:

1. Evans, M. R., Stamps, R. H., & Lemaire, F. (1996). Physical and chemical properties of coir dust. HortScience, 31(6), .
2. Lemaire, F., Stamps, R. H., & Evans, M. R. (1998). Coir fiber as an alternative to peat in media for tomato greenhouse production. HortScience, 33(6),
3. Meerow, A. W. (1994). Growth of two subtropical ornamentals using coir dust (coconut mesocarp pith)