JARS v63n4 - Tips for Beginners: Coir - A Wise Choice

Tips for Beginners: Coir - A Wise Choice
(Modified from the Jan/Feb 2009 Bulletin of the BC Council of Garden Clubs

Coir (sometimes referred to as "cocopeat") is abundantly available and is an easily processed natural by-product of the coconut farming industry. Coir is essentially the coarse granular "dust" that is generated when the large, spongy husk of a coconut is ground up to remove the stringy fibres that are used in making mats, rope and as stuffing. The dust can be adapted for use as a growing medium.

As far back as 1949 botanists and horticulturalists recognized coir as an alternative to peat, which is partially decomposed organic matter that has accumulated in a moist environment. So why have environmentalists and gardeners not begun to embrace this product until the last ten years, and why is peat still the more commonly sold "peat" product in many garden centres?

Hume (1949) years ago extolled the virtues of coir and the excellent growth obtained with various plants when this coir dust or, as he called it, "cocopeat," was used as the growing medium. Modern greenhouse operators have adapted their fertilization regimens to meet the unique traits of coir, and some growers recognize how certain plant species thrive in this medium better than in all others.

Hume was a prophet before his time. It is only in the last ten years that his words of wisdom have percolated through the often conservative ways of international horticulture. In the 1970s and '80s, initial tests in Australia and Europe indicated that coir dust could function remarkably well as a substitute for peat in soil-less container media for plant growth. Several Dutch companies have in fact been using coconut coir dust in production media since the 1980s, and the Royal Botanic Gardens at Kew is currently shifting most of its plant production into coir dust-based media. Sri Lanka (where over 2.5 billion coconut fruits are processed each year) has become the leading processor of what had previously been considered a waste product into a form suitable for horticultural use.

Coir is available as cubes, bricks and loose. It is a product that is easy to use and easy to store. The cost is extremely reasonable - sometimes cheaper than peat - so there is no reason whatsoever not to use it as a peat substitute.

Editor's Note: Many of us rhododendron growers use peat for many purposes - either in soil-less potting mixes or as an additive to soils when planting temperate rhodos. The natural process of creating peat takes thousands of years, which is why sustainable large-scale peat extraction is impossible. Peat bogs are rich in a diversity of plants and wildlife, and with 80% of the world's peat lands now destroyed or damaged, their conservation is becoming increasingly important. A way to help achieve this is to stop utilizing peat in gardening. Consequently, I am now using coir instead of peat as much as possible. So, if your garden centre does not carry coir - ask them to, and try using it. I believe that it is our responsibility as active, responsible gardeners to use the most sustainably-produced products available.

Hume, E.P. (1949) Coir dust or cocopeat - a by-product of the coconut. Economic Botany 3: 42-45