What Do You Think Of Coconut Coir?

Steve Marak samarak@gizmoworks.com
Wed, 28 Jul 2010 16:06:31 PDT
This is a subject that seems to be coming up on a lot of lists I'm on. 

There's some confusion because there seem to be several closely related 
products. I'm aware of three: fibrous coir, coconut husk chips, and coir 
peat (obtained usually from the dust generated when producing the other 
two).  All are obtained from the husks of coconuts, and the stories I hear 
about them seem to be similar, but they're rarely interchangable in use. 
Fibrous coir has many non-horticultural uses, too. 

With good quality bark becoming more expensive and harder to get, many 
orchid growers are looking at coconut husk chips as an alternative, and - 
since even among fanatic plant-growers few groups are as fervant as 
orchidists - I've done a lot of reading in those circles (plus I'm an 
orchid grower too, and I hate repotting). Some are also using fibrous coir 
as a substitute for long-fiber sphagnum.

Most people seem happy with the water-holding qualities of all three 
products, as well as their stability in use (less repotting). The question 
of salt, and how to remove it, is always the big one - there are many 
reports of people losing plants after moving them to a coir-based medium, 
and it's always blamed on salt, though I don't know how many people 
actually test to be sure. Salt content is reported to vary widely 
depending on source.

At any rate, it's always recommended to thoroughly wash the fibrous coir 
and coconut husk chips, soaking them for at least several days and 
changing the water regularly, before using it. If you're going to use a 
lot of it, I'd recommend buying a cheap "Total Dissolved Solids" meter. It 
won't produce lab-quality measurements, since they measure using 
electrical conductivity, but it's good enough to give you a baseline on 
your tap water (or whatever the source of your rinse water is), and to 
compare that to what's shown after the coir has been soaking. When the two 
numbers get fairly close together, we assume that we've done all we can do 
just leaching with our tap water.

Some have looked into it much more deeply - Bob and Lynn Wellenstein, at 
Antec Laboratories, suggest that after water-soaking the coir, you soak it 
in a solution of calcium nitrate and magnesium sulfate, to help remove 
sodium and potassium ions which may be adhering to the surface (and which 
may not be removed by just a water soak). Here's a link:


I've tried soaking coir peat, too. As you'd expect, it's a dirty, 
unrewarding task which leaves you with a sodden glob of muck. I've read 
that coir peat is much more thoroughly washed by the time we get it, and 
that additional soaking isn't necessary, but can't verify that. We haven't 
used that much of it. So far, we're happy with the chips we've used for 

Probably more than anyone wanted to read or know ...


On Wed, 28 Jul 2010, Mary Sue Ittner wrote:

> As I recall there were some negative responses and some positive ones about
> using coir. On a recent trip to South Africa, I helped Rod and Rachel Saunders
> repot some Scadoxus to sell and they were growing them in pure coir, nothing
> else. When I asked about this, remembering that people had said they had lost
> things using coir, Rod told me that you needed to wash it many times before
> using it to be sure that you have removed the salt from it. But then they
> found it worked quite well. It reminded me that I once heard a lecture on
> insectivorous plants by a man who had written a great book about growing them
> and he lost everything using coir, but I don't know if he washed it first.

-- Steve Marak
-- samarak@gizmoworks.com

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