Hello Arthur, always a pleasure to chat to one of me old mates. I did some research on coconut fiber as it was generally lousy for me. Apparenetly the chief problem is a substance called taurine which is present in coconut fiber. It is very toxic to epiphytes. We recently paid a visit to NE Brazil, which has millions of acres of coconut grove. Although we did not see all of them we did see quite a few and I never saw an epiphyte of any description growing on any coconut palm. Hope you're enjoying the cricket...

Ian, taurine might be the problem, but consider this orchid grown by an "expert"
in a treated pine bark /coconut chunk mixture.....
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I have had terrible results with some Genera and coconut fiber as a mounting material is useless. But why would a softcane grow so well. Perhaps taurine is selectively bad only to some Genera. Anyone have any idea?

I don't know what taurin is but I love coco as a potting medium. Here in the US we soak and rinse it three times prior to use to remove salts.

I use the chunks for any moisture loving orchid - phals, paphs, bulbos, oncids, phrags. I mix the chunks with charcoal and large perlite.

I use ground coir, also rinsed three times, mixed with 50% small perlite for years for anything needing "dirt" to grow in.

I use the string coir to line baskets to keep the media in or to use around the roots of some of the small vanda types to hold more moisture around the roots.

On another forum, many of the Aussie members swear by it. One of them raises many phals out of flask and he insists his way in the only way to do it..........but that's another story :>)

Brooke

Ian, I think I posted in response to this a while back, but I'm not sure if I got a reply. I've done google searches as well as pubmed literature searches on the effects of taurine on plant growth, and I can't find a single article online that talks about negative effects. The only primary research article I could find was the effects of taurine on wheat growth, and it actually enhanced growth.

Did a search for taurine and coconut. Nothing, no articles.

Where is this information from?

The only thing I know about taurine is that it's in energy drinks.

I've heard experienced growers both swear by and swear at coir and no sooner will you hear one of them say that orchid X hates coir chips when another grower will bench an outstandingly well grown orchid X potted in 100% coir chips. Most of my epiphytes are grown in coir mixes mainly due to needing a more water retentive mix when Melbourne brought in water restrictions. I grow my Cyms and nobile Dends in 100% coir and get good results. I grow my Sarcs and Australian Dens in 1 coir: 1 bark: 1 scoria and they've been growing well in the 3 years since I changed over to coir. Ealier this year I switched my Masdies from sphagnum to 100% coir and they seem to be growing well.

As far as why there are successes and failures, I think water retention does have a role in the problem. I also get the impression that it might compact too much over time, so what works in the first year fails in the second. Coir is generally held in high regard by Cym growers. However, a lot of Sarc growers complain that Sarcs grow well for the first year in coir chips but go downhill in the second year which would fit with the mix losing its structure more quickly than bark. I assume the addition of bark and scoria in my mix stops the coir compacting the mix too much.

There also seems to be a wide range of quality in coir. I buy graded and seived coir chips from one of the local orchid nurseries. It is unbranded but is comparable to Orchidmate. It is supposedly washed enough to be used without presoaking but I soak it in MgSO4 and wash it anyway. In the past, I have bought coir from Casetech, which was ungraded, full of fines and probably not suitable for anything but Cyms. The Brunnings brand coir was just as ordinary as Casetech but had the added disincentive of containing Nitrophoska granulated fertiliser. It's a bit hard to compare good and bad experiences with growers attribute to coir without knowing what type of coir was being used.

Andrew, thanks for the Sarcochilus potting recipe. I'll give it a try.