Bark Products from New Zealand and South Australia for Growing Orchids in Australia 🇦🇺

Gardening and other hobbies continue to keep Bob Bishop sane and bring some reliefs from the toil of work. Whilst he may have been somewhat facetious and humble in stating that he “ha[s] been growing orchids quite badly for over 40 years”, Bob has nonetheless done many other things throughout his life. Those who wish to search LinkedIn to discover his professional past and present will be disappointed to find nothing, as he has left LinkedIn a long time ago to avoid being hounded by representatives and bashed by Indian, Chinese and Russian companies looking for ‘partners’.

The questions remain: who is Bob Bishop, and what transformations and reincarnations have brought him from his variegated past to his multi-coloured present? In the beginning, Bob did a trade, and then was off the forum, so to speak. After acquiring electrical engineering, electronics and later a business and marketing management degrees, he ran a couple of divisions of multi-national companies in Australia, and then returned to the trade designing, building, programming and commissioning control systems for a variety of projects such as automating a couple of diesel generator power stations, including that of the famous Christmas Island.

Bob freelances nowadays, finding plenty of work in Canberra, Emerald, Sydney, Melbourne and a few other places, whilst considering himself fortunate for not having to tolerate idiots anymore. Still very much in demand and going strongly from year to year unabated, Bob has indeed proved himself to his own satisfaction, even though he had confessed to wanting to be a nuclear physicist. Looking back on his proclivities, he regarded himself to be first and foremost a practical person rather than a master of high-level algebras and far-flung theories.

In any case, we can celebrate not just Bob’s longitudinal achievements but also his particular brand of practical magic trumping theoretical sorcery! The loss of hard science to acquire his academic talents is the gain of gardeners and fellow orchid admirers to learn from his trials and errors as well as his knowledge and experience. As one can see on reading his sizeable article below, Bob has been able to apply a broad approach to experimenting with not just barks but also various potting materials and fertilisers, including Aquasol, Nitrosol, Basecote slow-release fertiliser, Osmocote Exact, Peters Excel Hi K, Stimulizer, B-tonic, Biomin calcium, blood and bone, charcoal, coco husk, diatomite, dolomite, lime, peat, perlite, scoria and sphagnum moss.

This article has been prefaced, extended and edited by SoundEagle to suit the multimedia styles and dynamic contents of the website. You may initiate conversation or reply in the comment box below. In addition, you can click any image below to comment on each photo in the article.

Bark products from New Zealand and South Australia for growing orchids in Australia

Imported bark – the current status.

I would point out that the full page ad being run extensively in the orchid magazines at the moment with a comparison table for raw bark versus ‘naturally aged’ bark is misleading, in my view with respect to Australia, not that I have ever found any pathogens in raw bark before anyway. I have occasionally found fungus in composted bark in the past though. The microbes and other beneficial organisms develop over time anyway. The main thing is that ALL BARK PRODUCTS IMPORTED INTO AUSTRALIA HAVE TO BE HEAT TREATED TO KILL ANYTHING ALIVE IN THE BARK! DAFF consider bark products to be a threat to our native plants and insist on heat treatment to kill off any possible nasties. If the product is heat treated properly there should be nothing alive in it anyway – if there was something living and it was discovered by DAFF the shipment would almost certainly be destroyed.

I would also point out that the heat treatment is expensive – possibly more than the cost of the actual product to produce. A company in New Zealand heat treats both brands of New Zealand bark as far as I am aware. The heat treatment process takes about 22 hours I have been informed – a long time. There are temperature probes placed through the pallets of bark to make sure that the heat is even and through all the product. It is highly unlikely that any pathogens, beneficial organisms or otherwise would live through that. DAFF insist on it and will not even accept fumigation – it has to be heat treatment.

My experiences with growing media in the last 15 or so years – I have been growing orchids quite badly for over 40 years!

Many years ago I used to grow orchids in bark from a well-known Sydney supplier until it was not as good as it used to be, in my view. The trees here are cut very young and the bark does not have time to develop properly. The higher temperatures in Australia also means that the trees grow faster and even the wood is not as dense as when the trees are grown colder and slower. I have always used raw bark and not treated bark – the only treatment I used was to soak the bark for 5-7 days in water, dolomite and blood and bone – I did not use the ‘accepted’ chemical treatment at the time with lots of chemicals and urea – I hate urea. I also used some Aussie bark, from Queensland I think, years ago that was boiled – that was as tough as old boots and lasted for years. A friend of mine has plants still in that bark and they have been in it for 14 years with virtually no breakdown or PH problems!

I then went to Debco bark and it was not as good, in my view, over time also.

I then went to the South Australian bark and got sick and tired of it breaking down fast, pH problems as it broke down and having to use a lot of lime and dolomite to correct the pH. Re-potting everything every 12/18 months was not for me.

Coco husk appeared to be the answer. I used coco husk and perlite for some time with quite a deal of success but it appears that the Sri Lankans found they could sell all they could produce and appear to have become ‘slack’ – lots of long strands in some bales that had to be stripped out – variable salt levels – I had to wash one lot 7 times over a period of many weeks to get the salt out – checking all the time with an EC meter. Some batches and brands appear to be better than others. The final straw was when I knocked a Phrag one day and it fell out of the pot – no roots – 13 months standing in water and using some lime, dolomite and fertiliser all combined to break it down so fast that what was in the pot was sludge (mud)!

I went looking for a better growing media. I investigated scoria, sphagnum moss, perlite and peat, ground tree fern and a lot of other things. I experimented with all of them and found that the best thing for speciosums in my growing conditions was a combination of Maidenwell diatomite, bark, perlite and charcoal. I then found it was impossible to get good quality graded charcoal and Maidenwell went bust again! Dead in the water again! Be careful with diatomite, there is another brand available and I hear it is from sea creatures and full of salt! Not good for orchids – it has to be from fresh water creatures and the diatomite that is now available is also very small. It is sold as ‘Kitty Litter’ and also to soak up liquid spills. The Maidenwell diatomite was available up to 15mm chunks – it was great stuff.

I saw Kiwi Orchid Bark at a show in Sydney and I was quite impressed. I then went to the conference in Perth and met and spoke with Fred Clarke from Sunset Valley Orchids – Fred uses Kiwi Orchid Bark exclusively in his nursery and is, in my view, one of the best orchid growers in the world. I also spoke with Hans van der Ven from Taranaki Bark Products (Kiwi Orchid Bark). I also spoke with the representative from Besgrow (Orchiata) and viewed and handled their product – my impression was it was better than the SA stuff but found it quite flaky and quite soft and easy to break in my view.

Anyway, that was the way it was.

I had discussions about taking on Kiwi orchid Bark but the outlay straight out of the pocket was quite substantial for a 40 foot container and I hesitated for some time. I waited until Garden City Plastics had stock of Orchiata in Sydney and I was, in fact, the Sydney office’s first customer for the bark. I took it home, opened up the 3 bags and I was less than impressed! There was a lot of leftover fines or something from the ‘naturally aging’ process to the point that I had to wash the bark quite heavily to get rid of the muck! I found this particularly with the small size, the first I opened as I had seedlings to pot up. It may have been a bad batch, I do not know. I then decided to put my hand in my pocket for a 40 foot container of Kiwi Orchid Bark – it was a substantial amount of money with no guarantee of recovery! A fairly high risk I think but I was committed.

I have found the Kiwi Orchid Bark extraordinarily hard and very dry – quite chunky too. It is apparently taken off 25 year old trees so has had good time to thicken and develop properly at a relatively slower growing rate in the cooler New Zealand climate. It is slightly water resistant due to the natural resins in the bark from the pinus radiata trees – it is natural. Orchids grow on natural bark on trees in the wild – it is not treated, composted or ‘naturally aged’ in any way on the trees of course. That is how they grow in the wild and we all try to replicate the natural conditions to grow our orchids do we not? I decided to use my old method and soak the bark for 5-7 days in water, dolomite and blood and bone. This takes the waxy/resinous surface off the bark quite quickly instead of having to wait for the little microbes to get to work and do it for you. Also the blood and bone appears to compensate for any possible nitrogen draw down that may occur with fresh mix. I have always used blood and bone with most new plantings anyway and also use it quite regularly on speciosums in particular, but other orchids as well, when I have the time. The exterior of the bark nugget holds water far longer with this treatment. A friend of mine is using dolomite, lime and Aquasol to good effect for the same result. I prefer not to use Aquasol as it is quite high in nitrogen and encourages sappy growth and not flowers. If I was to use anything chemical for my process it would be Nitrosol. The other thing I found is that Kiwi Orchid Bark does not release a lot of tannins when soaked this way although I have seen scientific reports that claim tannin does not affect orchids anyway in mix.

Many customers do not even soak the bark at all and just use it straight out of the bag – I do not have time to water often enough to keep the orchids going until the microbes get to work and take the waxy finish off the bark and so lightly treat the bark with my soaking method.

I have also been fortunate enough to find some really good hardwood charcoal from Renewable Carbon Resources Australia from Charleville in Queensland. Really hard, well graded and top quality.

I have had some plants in my new mix of Kiwi Orchid Bark, Chillagoe perlite and RCRA charcoal for over 12 months now – Phrags growing standing in water with added dolomite, lime, Basecote slow release feriliser and blood and bone dressing – took one out recently and the bark that is permanently in water is as hard as the day it went in. I repot my Paphs and Phrags every 12-15 months anyway as they love new mix and roots grow like you would not believe.

I have been growing a variety of natives, Paph and Cattleya seedlings – all the same varieties as bought from nurseries – in my new mix, the same mix using Orchiata bark for one lot and the SA bark for another lot. There have been at least 10 plants of each mericlone/seedling in each mix – a fairly extensive trial as you can see. All receive the same watering and fertilising regime. I can say with great conviction that I will continue using Kiwi Orchid Bark exclusively as the root and plant growth I have seen are much better than in any of the other products in the trial – end of line! That is my experience from a 12 month trial of my own. After 12 months I am also finding some pH changes starting to take place with both of the composted/’naturally aged’ products but not with the Kiwi Orchid Bark. This experiment has been conducted in my growing conditions, just about everyone has different growing conditions and may have a different experience.

I often wonder why people bother about trying to get bark wet all the way through. The roots stick to the outside of the bark and do not care what is inside the nugget. The really hard bark centre lasts longer and does not break down or have PH problems in the same way composted and ‘naturally aged’ products do – way more important for longevity of the mix in my view. Wet through and the bark breaks down much faster I would think?

I do not have time to water all that regularly and I am finding that every 2-3 days in summer is fine with the lightly treated Kiwi Orchid Bark. What I am finding is that when the mix dries out a bit on top the roots go straight down into the mix looking for water – that is a very satisfactory result. Even Laelia anceps roots are going straight down into the mix and not into the air and out of the pot – I have never seen that before with any other growing media that I have ever used. Most pleased. Laelia anceps hates anything that stays moist/wet – coco husk, perlite and peat, composted bark and sphagnum moss most of all from my observations. I have tried all those mixes and they do not suit how I grow my orchids. They do suit others of course.

I am now growing Masdevallia, Dendrochillum, Maxillaria, Lycaste, Coelogyne and the like in small (No 2) Kiwi Orchid Bark, 5mm RCRA charcoal and medium perlite mix and they are away and growing better for me than ever before. I am considering upping the perlite size to coarse – experiment in progress. Basecote slow release is helping too – low nitrogen (11). No longer available as Garden City Plastics did not sell enough tonnage of the product. I have found a third generation Osmocote Exact that is almost the same formula and it is performing really well too with my orchids. I also use Peters Excel Hi K as a spray occasionally along with Stimulizer and/or B-tonic. Biomin calcium is also part of the spray regime – spray it on and it is in the plants in 4 hours. As my mad passion is Paphs and Phrags this is great stuff – both of these are generally calcium lovers. I also use dolomite regularly.

This is working very well for me in my growing conditions – the results may be different in your growing conditions – the usual thing with any media and growing method.

I am more than happy with the results from growing in Kiwi Orchid Bark, RCRA Charcoal and Chillagoe perlite so far. I think you can see why quite easily from the photos below.

Experiments are continuing – I am finding that some of my mixes appear to be a bit fine perhaps and may have to go up a size or mixed sizes – that is also working well for me too.

Further information about Kiwi Orchid Bark can be obtained from Taranaki Bark Products website

And Sunset Valley Orchids (Fred Clarke) website

My email is

Bob Bishop

Here are a few photos of root growth in Kiwi Orchid Bark.

These first photos are from Taranaki Bark Products website.

A speciosum var. speciosum I re-potted nine weeks ago, with all roots removed, in my mix.

Laelia tenebrosa seedling – new roots after 9 months in my mix – I expect this to flower on the new growth.

A youngish Paph – re-potted 9 months ago in my mix – the new roots were not on the plant when it was re-potted.

Brassia Rex re-potted with virtually no roots in December – 5 months ago at the very outside – in my mix. Should have put it in a bigger pot I think.

A mature Paph (Julius) with new roots since re-potting 8 months ago.

A small division of Laelia anceps that was broken up over the Xmas break – new roots going straight into the mix.

New roots on a Dendrochillum that was re-potted during the Xmas break. Roots stuck to the pot quite heavily as well – I did not get all the roots out.

Update 15/05/2014 – a testimonial received recently from Fred Clarke of Sunset Valley orchids. Fred uses Kiwi Orchid Bark exclusively straight out of the bag but he is also known to water and fertilise a lot – that would not suit me – I prefer to use my soaking method to retain a bit more moisture as I do not have time to water too often.

From Fred Clarke;

Kiwi Orchid Bark has been used exclusively at Sunset Valley Orchids for the last 5 years. Over that period, we have grown and finished in Kiwi Orchid Bark over 100,000 orchid plants, including Cattleyas, Paphiopedilums, Australian Dendrobiums, Catasetums, Cymbidiums, Zygopetalums, Stanhopeas, and other genera. Compared to other potting media that I have used during my 35 years of growing orchids and operating a commercial greenhouse, I have found it to be a superior product, and I believe that it is the best orchid potting media available today.

There has been a lot of propaganda regarding the benefits of treated bark (also referred to as aged or composted bark). However, there are some drawbacks to composted bark. The composting of any organic material, including bark, causes acidification, the lowering of pH. To counteract this problem, lime is added to raise the pH back to neutral. Liming is effective in raising and holding pH for about 18 to 24 months. After that, pH begins to drops. When pH drops the root system may suffer. This, of course, is a real problem, as root health is essential to growing good orchids. It is possible to offset the pH drop by reliming composted bark. I am not sure how re-liming is best accomplished, as orchid potting media is a soilless media and very open and well drained. Research should be done on how best to accomplish this for growers using composted (aged) bark. One solution would be to re-pot once the pH begins to drop: however, knowing when to do that requires constant monitoring and extra costs.

I have experienced no such problems with Kiwi Orchid Bark and that is one of the main reasons I use it. Kiwi Orchid Bark holds up extremely well and exhibits little to no appreciable decay, even after 3-4 years of use.

All bark imported into the USA or Australia must by law be fumigated with methyl bromide or heat treated. These important regulations are to assure that no unwanted organisms are introduced. Kiwi Orchid Bark is compliant with these regulations and as a result is 100% free of weed seeds and pathogens.

At Bark Products Taranaki, every load of bark that comes in is inspected by the owners and followed through the milling process to assure the highest quality. The year to year consistency of Kiwi Orchid Bark has been exceptional. I am convinced that it is the best orchid bark on the market.

Really pees you off! This is a really nice pendulous Cymweedium I bought from a well known grower. I will not put a name to the orchid as it will be a dead giveaway as to who it is – I have already had my few words to say! Fresh bark in the top – thought it had been repotted but it was going backwards. Took it out of the pot – the pic on the left is what was in the bottom – totally collapsed and rotten coconut husk and who knows what else! Looks like mud! The bark was no good either – heavily composted and already showing nasty signs of acidification and turning into mud. The roots were rotten in the middle and totally dry and dessicated on the outside. Silly thing is the darn thing is putting out a heap of new growths! I cut the bottom half of the root ball off and cut the whole centre of the root ball out with a sterilsed steak knife – it works a bit like a saw to be honest – have 40 of them. Certainly had a fresh pair of disposable gloves on as well. The pot also went in the bin. Has now been potted up into a nice fresh bark, charcoal and perlite mix and a handful of slow release on top in a water well (Anova) pot. The smaller Anova pots do not carry enough water for my liking but the 200mm and 330mm pots have had a substantial raise in the water are and are now good. I expect flowering will be down but the root ball will take of – have proven this method and it really works well for me. The plant is also quarantined until I can see what is going on with the new growths (signs of virus). There are no signs at the moment and as the plant has been heavily stressed I would expect the new growths to be showing signs if it has virus but one cannot be too careful or could finish up throwing away at least a couple of hundred plants!

7 thoughts on “Bark Products from New Zealand and South Australia for Growing Orchids in Australia 🇦🇺

  1. As always SoundEagle – a very informative article including interviews with two very experienced growers .I thank Bob Bishop & Fred Clarke because their trials & results save us all months & years of time & answer questions that we’ve all thought about but never researched. Personally i was grateful to read about Laelia Anceps & her wayward root growth habits & have a resolve for this issue. After reading both men’s experiences I felt more at ease about using a PH & EC testing kit because I felt empowered to take better responsibility about what was going on in the pots & not just taking pot luck !! The feeling I had was something like a cook watching master chef if you get my drift .Of course the article covers something very close to our hearts –Kiwis , i hear you ask ? no — bark & I mean all bark & no bite , all going well ! Depending on the genera that you grow & several are referenced in this article & the quality of the bark you use all has a huge bearing on how often re potting is needed to be done .At the end of the day the more care & attention to detail , the better the orchids are & the better the results & the better the rewards & accolades & success .You could say it’s a win / win situation.

    Liked by 1 person

  2. Pingback: Culture Sheet: Oncidium Intergeneric (Dancing Lady) Orchids | ✿❀ Queensland Orchid Society ❀✿

  3. Good Morning, I manufacture charcoal specifically for the orchid industry. It is made on our farm on the qld nsw border from aged ironbark and prepared in a high temperature process that allows it to hold about 4 times its weight in water and will not breakdown for 100’s of years. It has a slight liming effect so helps neutralise acidity caused when bark is mixed with it. It is available in small or large quantities.

    Liked by 1 person

    • Hi Roger, thank you for the information on your particular brand of charcoal. Please be informed that your website cannot be located initially because its web address is incorrectly specified by you. The correct web address is, and more specifically,, whose contents, for the benefit of readers here, begin as follows: Biochar ‘Neat’ product

      Biochar is used to increase microbial activity and overall health of soil. Our Biochar is produced from local hardwood in an almost smokeless method.

      Biochar is added to the soil allowing the soil to increase microbial activity and overall health of the soil. Biochar will hold approx 4 times its weight in water and will continue to absorb and release water and nutrients, and provide a home for the soil microbes for hundreds of years to come.

      It’s a once in a lifetime application, all the while improving the soil conditions for growing healthier plants.

      When initially applying biochar it will absorb water and nutrients and provide a haven for the soil microbes essential for plant health. These are stored for later release to the plants.


  4. Thanks for your comments SoundEagle. I actually make charcoal for the orchid industry in grades of 5-12mm, 12-20mm and over 20mm. I now have improved my website giving more information and welcome any enquiries.

    Liked by 1 person

  5. Pingback: Phalaenopsis: Novice’s Orchid, Mother’s Day Gift and woodlandgnome’s House Plant ✾💃🎁🏡 | ✿❀ Queensland Orchid International ❀✿

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