Potting media containing leaves and twigs

[Bjorn]

In his books on orchid cultivation the late Australian J.N. Rentoul, advocates for potting mixes containing twigs and leaves, primarily based on oak, casuarina etc. to supply "food" for the plants. Anyone that has had experiences with such mixes?
Rentoul wrote a series of books covering almost any aspect of orchid growing during the 1980'ies and I have been able to aquire most of them. Anyone in this forum that has had any experience with his way of orchid growing? Some of his ideas have been advocated for in this forum as well, the use of blood and bone was obviously one of his tricks, another one is to add shredded leaves and twigs.
Personally I have mainly used (traditional) bark mixes with perlite and moss, and am quite happy with it. However there is something that lack in these mixes. I will now describe an experiment that I started a long time ago and unfortunately details are lost but here is the essence: Some 10-12years ago I made a planting into some old plastic boxes approx. 25x35cm 15cm high with drainage holes in bottom and side walls. Two of them; in one I put some micranthums I had, in the other one a collection of henryanums. That compost was based on bark, moss and expanded clay with some oyster grit as far as I remember. And that is the end of the story - even during years of heavy neglect the plants are still prospering, and have flowered regularly ever since. Right now my henryanums have some 10 flowers and buds and the micranthum seems to get some 5-8 buds. All these plants came into Norway in the late 1980'ies or early 1990'ies, I got them around 1994, so I have no doubt they have been wild collected-probably from China. But they prosper in the same potting medium as they did 10 years ago, and with no signs of lost vigour. Do any of you have any good explanations to this? I feel that if we were able to replicate this one, possibly with the decaying matter of Rentoul, then much would be gained in paph. growing.
Any comments?
Bjorn

 

[SlipperKing]

welcome to the forum Bjorn!

 

[Bjorn]

Thank you Rick,
any views on the above? Additinally there is one thing that pussles me: Anyone heard about henryanum producing stolons? I might be wrong, but there are a few (2-3) plantlets in the Henryanum "flat" described above that looks as if they are on the end of short stolons approx. 10 cm away from mother plant. Can be seedlings as well, but I do not think there was ever a seed-capsule on those plants. I am not 100% sure since I do not want to dig into the compost to find out.

 

[goldenrose]

WELCOME, Bjorn!
Interesting ...... I have no explanation.
The potting media has never been replaced in 10-12 yrs? Have you been sprinkling leaves over the media on occasion?
It's a hard experiment to comment on, there are many details missing. What do you consider to be heavy neglect? If the plants are prospering & flowering, doesn't appear neglect is occurring. One would have to think that light, temps & watering is at levels that they need. You don't mention use of fertilizer.
Do you have any plans on unpotting to see what's going on? I would think that should be part of an experiment.
Keep us posted!

 

[likespaphs]

welcome to the forum

as a big fan of compost and composting, i have no doubt that the decaying leaf matter and sticks and twigs and whatnot added beneficial fungus/bacteria and other things including nurtrients which aid the plants in growth and have moisture holding properties.

 

[NYEric]

Welcome from NYC! i was sent a package of leaf litter and other materials. I never used it as requires watering and microwaving to sterilize!

 

[biothanasis]

Welcome to the forum Bjorn!!! Well done on growing!!!

 

[SlipperFan]

Welcome, Bjorn.

I, too, was wondering if you had never done anything to change the mix -- adding, or fertilizing, nothing in 10 years? That's something I dream of...

Pictures, please.

 

[KyushuCalanthe]

Well, sounds like a dream come true! I too would love to be able to pull that off. The only thing I grow in one place like that are mounts!

 

[Bjorn]

Guess that I should add some more info here; to describe my growing conditions a bit closer, let us start with the environment. I grow in a heated greenhousesome 13 sqm, kept at intermediate temperatures, that is something like 12-13 degrees C minimum at winter. Most of the time the winter daytemp has been like 16-18 degrees or so. As far as I remember, the plants, probably 5 of the henryanums were pottet around 1996-98, in 98 we got our first child and that was probably the start of the "neglect". By neglect I mean that conditions were watched, but not optimised, neither humidity nor care like repotting. Subsequently, during these years many of the potted (priceless) wildcollected plants(paphs) i had died(armeniacum/micrantum/delenatii/malipoense). As it happens, I always fancied automasation and during these years the orchids were subjected to experiments(home-made automatic misters and watering) that resulted in quite wet conditions. I found out that this was of course excessive, probably fine for some phrags but everything was dripping of moisture during 2/3 of the year. My orchid collection is something like a few hundreds plants 3-400?? mostly paphs, Cattl and dendrobiums (SEA-types most mounted on oak). Watering has always been overhead with a hose.
I live in the countryside and my water is during summer taken from a small pond in a bog that is a part of our property. The water is slightly acid (around 6.8) and has a TDS of approximately 50ppm so it is well suited for orchids. During winter I have to rely on rain water collected from the greenhouse roof. It is collected in a 1400 liter tank, but as it happens this is not sufficient so that during late winter I normally have to refill either from the bog or by shuffeling snow into the tank. An aquarium heater keeps the water temperature at 24degrees Centigrade.
Back to the pottings: All this overhead water made the henryanums and the micranthums suffer by algae and moss growth. To some extent layers of a kind of velvetly agae of up to several millimeter covered the older leaves. During these years the plants were subjected to small doses of fertiliser. Not on a regular basis, only occasional and when, then only at a few hundred ppm TDS concentration (guesstimate 250-300ppm TDS once every 3 weeks during summer). The henryanums did not love the conditions, and a couple died. This went on for some ten years, and during that time of "careless" growing, most of the henryanums survived and even flowered. A faint memory tells me that at one occasion some 3-4(?) years ago, one henryanum got pollinated, probably by a fly, that is most likely. From the back of my head I believe to remember that I sprinkeled the seeds over the compost as well just to see what happened. I did not follow up and two years ago I decided that I should rejuvenate my interest in orchids, started repotting etc and installed a fogger to get humidity up and so on. The surface of the compost was slowly overgrown by moss (probably the kind you call sheet-moss). The last year or so, climate has been adjusted by use of what we call a heat-pump. This is very similar to an air-conditioner being capable of heating and cooling if necessary. I was a bit sceptical when I installed it last year, but it works very well. How long may be an other issue though. Now climate is adjusted to approx. 17-18 degrees at night and 28 degrees at day, during winter we will set it down to 13-15 degreesC at night and 25 during day. These have been the conditions during the last year. Humidity is kept around 70% but is 100% at night and drops to 50% in strong sun. One thing; I have additional lights on durin the winter, as much as approximatly 2000W HID lamps (HP-sodium and metal halide). But had to cut down on it due to the power bill. Has to use it during winter though, it gets dark up here north.
Back to henryanums: This summer I decided to remove the moss on the surface and noticed a few plants that looked smaller than the rest. I did not pay much attention to it until recently when I started to wonder about the origin of these plants. Yesterday I took a closer look and the conclusion is that most likely its results of that sowing a few years ago. The plantlets are BS or NBS it seems as if the base is quite intertweened with the roots of older plants. I found some 4-5 such plants. It is probably not stolons or runners as I thought earlier.
Apart from this, the interesting part here is the fact that the plants have been in the same compost for at least 10 years (I guess it must be 13?) and are multiplying in a "natural" (at least the pollination was natural) way in that same compost. What is the trick???
That my friends is the question I give you today, but I believe that we face a combination of factors here: The size of the container is probably important, big sizes, remember this one is some 25x35x15cm (13liter/3,5gallon) which makes the whole setup more nature like with respect to draining etc. The compost containing large amounts of expanded clay- perhaps as much as 1/3(?) together with bark, peat etc, and I believe some perlite as well. During the years some decaying matter has probably been added like old leaves etc, just enough to feed the mychohirza. The importance of the mycohirza is probably very much underrated and the fungii should probably be fed as well using organic matter. A sprinkling on the surface with partly composted leaves and twigs may be one way? Just to mimic detrious that is a part of their natural environment. Mineral nutrients is a difficult issue in this context. It is a well known fact that fungii does not take it easy on salts. Some tolerance does probably exist, but how much? I am currently feeding at a rate of around 450ppm TDS in every watering and although it gives great result, I am uncertain about my fugus-population, so I have just stopped feeding for the season. My sphagnum moss is however alive and growing at this fertiliser concentration so perhaps sphagnum can be used as an indicator for water quality?
So much for this time, excuse all the words, but I hope that we can collect some useful information through this thread.
Bjorn

 

[paphioboy]

Hi and welcome. I have used organic material in potting media before (fern roots and leaves), and the plants grow fantastic roots in it. Problem is, the media needs regular replacing, so I have since switched to more inert materials (charcoal, leca) as I am away... Care to post some pics?

 

[Bjorn]

I knew that one would come...
Sure I would like to, but right now I do not have the opportunity to take any pics. Furthermore I am extremely clumsy with those things as well. It is quite interesting that I have had those plants in the same container with the same potting media for so long(13years?). I believe it all started as an experiment to mimic nature. But that mix was made with a lot of expanded clay(LECA) of different sizes plus other ingredient, so you are not too far away. Perhaps the clue is to have a rater thick layer of perfectly draining material covered by a relatively thin layer (5cm?) of rather slow decaying compost? Including twigs etc.?
What do you think?
Bjorn

 

[NYEric]

I agree that having a large natural condition might influence the result, as would having the plants grow in moss an leaf litter as they would in nature.