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(1) Augusto Burle Gomes Ferreira
(2) Delfina de Araujo
(3) Francisco de Sales Carvalho e Silva
(4) Maria Esmeralda Soares Payão Damatté
(5) Waldemar Schelliga
(6) Roberto Agnes
(7) Nelson Barbosa Machado Neto
(8) Greg Alikas
(9) Ernie Anderson - This was the message that made me create this topic
(10) Luiz A. Menéndez
(11) Helio E. Marodin


Augusto Burle Gomes Ferreira (Coxim inventor and producer)

In the eighties, when I first noticed an excessive increase in the price of tree fern fibers (xaxim) due to the fact of it was on the way to extinction, I turned to the cultivation of epiphytes in coconut bark, which is a century old traditional custom in the Northeast of Brazil.
I sought to find a technique to re aggregate the parenchymatous tissue of coconut, something held as impossible by science (reaggreation by pectin, in this vegetal tissue), for it is in this tissue that plants seek their nourishment, and not in the fibers which have no use for cultivation,.
Once having mastered this technique, two ecological problems would be solved: the preservation of the species of Dicksonia selowii and the mangrove bushes and lagoons of the Northeast.
These are constantly being destroyed by the massive discharge of the parenchymatous tissue of the coconut by the unraveling machines.
Besides, it would still give the product the most convenient form for its utilization.
The small plants of the palm at first make their roots in its own bark, and after pass into the soil. The coconut bark is a nutrient produced by the coconut tree to nourish its offspring, in the first phase of their growth.
I even dare call it &vegetal milk".
This suggests that its high nutritive value does not depend on the tissue decay which is proved by culture on coxim.
It may be noted that the coconut bark when thrown on the field, will only decay totally after an eight year period.
Coxim is semi-industrialized product from the parenchymatous tissue of the coconut bark. It is good not only for the epiphytes but also for terrestrial plants.

The qualities worth mentioning in coxim are:

1- Auto-stabilizing of pH

According to the measurements made by the Department of Chemistry of The Federal University of Pernambuco during five years, the following averages were found:

NewpH 5,53
1 year usepH 5,72
3 year usepH 5,18
4 year usepH 5,35
5 year usepH 5,25

which shows in it an anomalous behavior for organic matter. Usually organic matter in the decaying process, becomes alkaline, while coxim preserves its acidity on a proper level for orchids.

2- Richness of Nutrients

Analysis made on ashes, by the laboratory at Superintendência do Desenvolvimento do Nordeste (SUDENE), found the following contents of non volatile elements:

Potassium as K2O 0,722%
Calcium as CaO 0,439%
Magnesium as Mgo0,234%
Phosphorus as P2O50,196%
Iron as Fe2O3 0,130%
Zinc as Zn 0,0029%
Copper as CuO 0,0025%
Mangases as MnO 0,0020%
Boron as B trace

And analysis to determine N - P - K concentration made by Instituto Tecnológico de Pernambuco had the following results:

Nitrogen as N0,46%
Phosphorus as P2O50,26%
Potassium as K1,39%

These results show only a lack of molybdenum and cobalt among micro-nutrients and a slightly low content of nitrogen. However, the analysis made by Prof. Milton Leinig from the Federal University of Paraná presented traced of cobalt.
I fertilize my orchids once a year with a mixture of castor bean cake and bone meal to complement nitrogen, plus Peter 20-20-20 to assure the extension of all nutrients so I can declare that cultivation in coxim is a low fertilizer consumption one. I should add that it is rich in silicon which is a catalyst of the absorption of the other plants nutrients.

3- Production of Micorriza rich environment

Spontaneous seedling of several genera (Dendrobium, Thunia, Epidendrum, Cattleya Caularthron, Phajus, Acample, etc.) budding from other orchids baskets. Other coxim users have the same occurrence in their nurseries. I don't remove the pods that appear naturally after flowering. By this, I don't mean that coxim is a cultivation media for commercial germination; I only noticed that with its use the greenhouse becomes an environment rich in micorriza fungi. 4- Lesser need for watering

coxim being a spongy tissue, it is highly absorbent. It may even absorb 200% of its weight in water. It also has the property, when in pots, of having its outer layer isolating the evaporation of the inner ones. So, its need of watering is smaller than that of several potting media. It must be noted that in this case the pot must never be totally dry: in opposition to other potting media, water does not significantly accelerate its decay.

5- Great durability

The durability of coxim, compared to other organic potting media, is quite great, in the equatorial climate of Recife, with great humidity (55% minimum, 98% maximum) its average durability is 4 years. In other climatic conditions it may last up to 8 years.

6- Sterilized products

The coconut bark naturally contains a lot of tannin, a substance that is a powerful bactericide and fungicide. Besides, coxim is pasteurized in its manufacture: it is slowly heated (7 hours) up to 80oC and remains at this temperature at least for 4 hours, being maintained at a 21kg/cm² pressure. As a result, I am sure I can provide the clients with a potting medium free from bacteria and fungi.

7- Easy handling

It is an easy-to-handle potting medium, after you get used to it. Besides, There is no case of allergic reactions known at this moment.

However, as nothing is perfect, coxim also has a few inconveniences and you have to learn how to deal with.

1- It needs some fertilizing

Its nitrogen content could be greater. This was minimized by the production of coxim E (enriched) which receives l,5% of castor bean cake and bone meal; but his is a product that I manufacture in a smaller scale.

2- Its volume varies

On absorbing water, coxim increases it volume in 7% (average) and upon drying it returns to its original volume. That is why the cubes should be placed in an irregular way. This does not affect the roots.

3- It needs washing

Washing before using is indispensable to remove the tannin, or else it will burn all new roots for about three months. Tannin, which protects it from leading pathogenic agents, is also a powerful herbicide. We recommend that it be immersed in water for 4 days for the granulated formula, 8 days for the cubes and strips and 15 days for the plates and rods. Those who have the facilities may test for tannin adding a littler water from the washing to a solution of lead acetate 1%. However it may be kept when wet for a long time (up to 6 months) to be used according to needs, not presenting any decay.

4- It brings weeds to the greenhouse

Greenhouses planted with coxim start having trouble with weeds. Any seed that falls upon it will germinate: from moss to trees.

5- It needs a change of habits

The orchid hobbyist must be willing to learn how to plant in coxim because each potting medium has its own requirements. To finish this, I shall read the conclusion of the Associate Professorship thesis of Prof. Esmeralda Payão Dematté, of the Horticultural Department of the Faculdade de Ciências Agrárias de Jaboticabal, Federal University of São Paulo (UNESP) "...among the potting media studied, pure coxim is the one that holds the most qualities to replace tree fern".

Text extract from the Associate Professorship thesis of Prof. Esmeralda Payão Dematée, of the Horticultural Department of the Faculdade de Ciências Agrárias de Jaboticabal, Federal University of São Paulo (UNESP) (1992)

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by Delfina de Araujo

There is no ideal substrate for all epiphytic orchids but until now the tree fern fiber is the one which congregates more qualities to occupy this place. Nowadays, the big challenge to the orchids growers is to find its substitute because the tree fern fiber commercialization is about to be forbidden by reason of the Dicksonia selowii's extinction. Although it has been replanted (unfortunately in a small extent), there isn't a true re plantation program. The consummation is bigger than the production because it grows very slowly. It can also be extracted from Osmunda, Cyathea and so on...
The purpose here is putting this question under discussion by knowing some commercial and amateur growers' opinion and experience.

The substrate should have many proprieties: It must retain humidity for a while without getting soaked, to be able to hold the plant firmly (a plant which is not firm never sets healthy roots), to be easy-to-handle and to be long lasting. Another important point is the substrate's pH, the efficacy of absorption's fertilizer depends on its acidity. Some cultivation media such as cork bark, nylon foam, palm's fiber (piaçava, Attalea funifera and Leopoldina piassaba) are inert because they don't have food values for the plant which needs to be integrally nourished by fertilizers. They are considered just a support. Some other cultivation media such as tree fern fiber, osmunda, tree bark, sphagnum moss and coxim are considered the genuine substrates because they provide food although the plants remain needing to receive a complement by a regular fertilizer application.

Inert cultivation media


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Francisco de Sales Carvalho e Silva.

chemist engineer, amateur orchid grower since 50 years ago.

About the big discussion about the universal ideal substitute for tree fern fiber, I have a chemical reasoning, I can't reason without the chemistry, I search a chemical explication in every thing. First of all, the process involving the substrate's aging must understood because the big problem is found exactly there and we had the preoccupation to do a work about this.
You cultivate the plant in substrate no matter which, if it is a orchid in tree fern fiber, sphagnum moss, piassaba, wood log or in any kind of substance and as a result of the passing time, you notice that it is growing older.
The big question is, what is the aging of the substrate?
We concluded that the substrate is being attacked for fungi, bacteria, or to put in another way, there is a very intense microbial flora which has an important place, indispensable to life in earth. This microbial flora decomposes the organic material, changing it into humus creating a series of substances which are important to the plants. This was our way, our work has been based on it.
Of course, plants can't eat a piece so nutrients must be soluble in order to be absorbed by them.
How can the plants get it, how is this process?
Precisely by the action of the bacteria which attack the organic residues provoking the slow decay until reach mineral kingdom under the form of simple mineral, nitrogen, hydrogen,, etc... So, if the substrate doesn't decompose, you can notice, at first sight, that is a bad substrate because it doesn't provide the elements the plant needs.
Why is the tree fern, without favor, the universal substrate?
Because it has an enormous amount of cellulose which is gradually decomposed, not too fast, it has a control on the decomposition and going on generating humus during a highly complex process. First, the group of germs comes in, all aerobes, then other groups, bacteria, fungi and so on. It gets a point where we will have the humus which is formed essentially by the decay of vegetal matter. That is something we can see every day. We assemble an amount of leaves, vegetal detritus, keep it humid, this material starts decomposing and, gradually, it takes an appearance of earth, dark, integrally returning to mineral kingdom. If the anaerobes bacteria get in, if the material is closed interdicting the aeration, it can generate compounds absolutely undesirable, anaerobes conditions which are not the ideal to produce de humus, creating a decayed, alkaline compost which can provokes serious problems .
When you pour too much water in the substrate, you provide an anaerobes medium, that is, the oxygen held within the water is wasted away because some reducing substances are generated inside the substrate, to put in other way, they are arid of oxygen and take it from the water, creating anaerobes conditions. Water in excess, among other things, is harmful because of this.

When you compact too much the substrate, you have the same problem. I am not well inclined to organic fertilizer although I am not completely against but it should be used very careful and with orientation because it forms a layer, a covering which closes the substrate also generating those anaerobes conditions.
There is a classical experience, take two plants with new roots, still green at the tip, put one into a glass and cover it with substrate very well pressed. Put the other one also into a glass but the substrate layer should be thinner, free. After some days, take them off, the first one, with a compact substrate, is dead and the other one, will be alive.
The nature gives us an important lesson about it. How do we find the plants' roots? Hanging, free, in the surface of the trees, of the stones or in earth extremely soft. A robust, well-fed, wonderful plant, in a very good cultural conditions, is, in general, found in ground where there are those leaves fallen down.
So, we know that a substrate which becomes anaerobes, without ventilation, is a harmful substrate. If it allows the aeration, gets decomposing, in a while, there will be the humus formation.

What is the humus?
They are chemical compounds, that is, fulvous acids, humus acid, humina which is a chemical substance not very well defined yet. In addition, it has a little of melanin, the same as we have in the skin, produced by the fungi, working, decomposing the vegetable matters. It is hard to say it is the most important but, at least, it is one of the most important components of the plants' life. It has a multiple action which allows and encourages the roots growth. It is also an stimulator, it encourages the absorption of many elements, nitrogen, potassium, as a matter of fact, it has a very important participation , indispensable to vegetal life. Finally, we can't conceive life without it.
There is a big, showy example and we saw it closely: The Amazon rivers. There are two groups, the white and the dark. Solimões is a white river and Negro is a dark one.
The fundamental difference is: The dark river lays down in rocky soil, where there is no clay and as the water is very transparent, we can see the profundity, we see dark because it has no color.
The other one runs through clayey soil, extracts a big amount of clay and has this turbid appearance. Who has been to Amazon, has already seen it, the meeting of the Solimões and Negro waters forming the Amazon river. One is dark, the other is turbid.
Those rivers overflow periodically, every year, inundating the parts of riverside lands, forming those big swamp lands over the woodlands full of dead leaves. It is known that the flora in dark rivers borders is very exuberant due to the high proportion of humus acid. The rivers extract it, carry and give it to the plants. As those overflows are really intense, some plants stay plunged and there is an enormous amount of humus acid.
Of course the other rivers do the same extraction however they have a high quantity of clay, that, combined to humus acid, finishes to hold, to sequester it. The clay is a holder substance as well as the humus acid is. There is a group of chemical substances which has the property of sequestrating. Certainly, when we talk about sequestration, we refer to metallic ions but the clay has an action very similar to them on the humus acid, the clay takes it away, out of circulation.
What does it mean? There is a big amount of metallic ions crossing over the water: sodium, potassium, iron, nitrogen and the sequestration is a chemical process, nearly to be physical, where the molecular body involves the metallic ion.
The perfect image is a capsule involving the ion. The plant has the capacity to assimilate this and ruptures the sequestration. In this process, the presence of humus acid is increasing every day, we water the plants, giving them a series of dissolved metallic ions, calcium, magnesium, potassium which are hold , absorbed by the plants. So the water of white rivers (Rio Solimões and some others) are poorer than the water of dark rivers and the flora is not so exuberant.
This is the basic evolution of the substrate: a decomposition until reaches the point to producer an amount of humus acid. The decay is getting increasing and reaches a good level where the supply is the ideal to the plant. Then the quantity of substances thrown into the substrate is so high that reaches an insupportable, an excessive limit and it becomes toxic.
The humus acid is an excellent stimulant (we can mention many other advantages) but it has two parallel problems, is a reducer and a sequestration agent. As a reducer, it takes away the oxygen doing a perfectly comprehensible curve: We have the substrate not yet decomposed, without humus acid, neutral to the plant, then, by the humidity action, propitious conditions are generated to the bacteria and they start to disintegrate and will form the humus, in the presence of humus acid.
The tree fern fiber with 6 months, a year of use, gets the ideal state where the acidity is not excessive. The pH level is good to the plant, giving the necessary substances. It has already disintegrated partially, internally decomposed, the bacteria have allowed the liberation of nitrates, potassium, nitrogen into their different forms - ammoniacal, nitric and so on. The assimilation is going on until to reach the level I've already told about and then becomes toxic for the plant. This level varies a lot because it depends on the humidity but the experience teaches us that a well worked substrate, not too much compressed, can last 4 years. Then, we can see clearly that the plants fall to suffer. However if the substrate has too much humidity, the decomposing is faster, if the temperature is high, it could be more intense.
To do an useful pH measurement, you shouldn't use fertilizers because they have, mainly the organic ones, a high pH level. For example, Chicken manure has pH 10 and the Ricinus communis' bran has also high pH. All those things modify the pH. The German growers have created the best way to water a plant, I've seen it in Swiss, they water more infrequently but when they do, they soak the plant to wash the substrate. It is a very smart thing because the substrate becomes saturated and the humus acid is soluble enough (not excessively). If the pH has not acidity, he is perfectly soluble. So, washing, the excess, mainly mineral salts, gets away and the substrate is recomposes. However we can not make the substrate new because we can not take away everything.
There is no endless substrate. Since the decay starts, it is hard to stop it. Even washed, the substrate remains full of bacteria. A cultivation medium was generated and the bacteria will work quicker than in a new substrate even after stopping the washing.
Basically, this is the substrate cycle.
We must reason, mainly, considering the tree fern fibers and then take the conclusion for the others.
Are pebbles a good substrate? No, they aren't. They have nothing to give to the plants. Everything the plants need, must be taken from the fertilizer.
In 1992, I have published an article in Orquidário about piassaba palm's fiber (Attalea funifera and Leopoldina piassaba) considering it as a promising substrate. It has very goods characteristics, it is porous but it formed in big part by lignin that doesn't decompose.
I opened a pot where I used it 8 years ago and it still was in the same condition I put it. So this substrate can't be similar to tree fern fiber.
There is another point that we couldn't anticipate. It seems to me that the microbial flora search for a place to stay. It doesn't born anywhere, it won't grow in rocks and I think piassaba has something which rejects, decreases the quantity and the quality of microbial flora. If there is no decomposition, there is no feeding for plants. Since is the microbial flora that feeds the plant, when we put manure, we are concerning about feeding this flora. It does a more specific disintegration, better for the plant, gives many forms of nitrogen amonniacal, nitric, disintegrate phosphates under many forms. So the disintegration made by the microbial flora is, no doubt about, better than ours.
Day by day, you must reckon on those microorganisms to help to do the decomposition. Piassaba is a good support but it doesn't have nothing to give, it is a bad cellar.
More than this, it has a harmful fungus which provokes skin and eyes diseases. Something very harmful.
The first time, I went to buy it, I was informed about a serious problem with the employees but I didn't pay too much attention. I am very strong for this kind of things, I'm hard to be attacked but I had a serious problem. It was enough to open the container and had skin and eyes problems. Of course, you can cultivate under hydroponics culture but it is a hard work, something extremely complicated, you have to deal with a lot of things, with deep concern.
About the coxin, for instance,I haven't done yet enough experiences with it but by the preliminary analyses I've done, I think it is a very poor in organic material and regarding to this point, it is closer to piassaba than to tree fern fiber.
I used it in some pots which rooted well. Rosário (from Quinta do Lago) has also succeeded with some pots, the roots were well established but we need four, five years to have a conclusion about.
As far as I am concerned, this thesis fell into a basic error. The major error is not to broach the humus acid. I think it is a little singular. Any book about vegetal nutrition gives an enormous importance to this matter, whole chapters and there are doctorate thesis developed on this subject. We can not considered this subject without analyzing the decomposition of the substrate. And when we analyze the decomposition of the substrate, we go into humus acid.
I saw some incredible things concerning the humus acid in Amazon region, it has really a great importance. It has unbelievable qualities.
The amount of humus acid in coxim is less than in tree fern fiber. The humus acid is one of the points of the cultivation but there are others like soluble salts, many kinds of salts, pH but, in my opinion it is the most important to be measured.
Don't have illusions about! A substrate which doesn't decompose, which lasts a whole life is a bad substrate.
Any substrate must be a cellar. I am not against or in favor to coxim, I just don't have enough information to believe in and I consider all those statements about its qualities a temerity. I don't agree with those statements. All those things have never been controlled.
I repeat, I don't have experience with coxim but, when we think about substrate, we must think about supplying nutrients. We started our article about substrate(Orquidário bulletin, Vol. 11, no 1, Jan-Mars 1997): "The substrate, no doubt about, is the base of a good orchids cultivation. It is not only support but also source of nutrients for the plants, it should present basic and indispensable qualities like consistency as support, good ventilation at the roots, capacity of retaining water, without being soaked, adequate pH e, at last, the possibility of decomposing generating humus ( particularly humus acid) and providing plants with the mineral elements they need".
Coxim is a good support, has consistency, good aeration to the roots but concerning the capacity of retaining water, it is less than tree fern fiber.
You can have millions of substitute to tree fern, but there is no universal substitute for tree fern fiber. If you hang an orchid in a tree, it grows well, if you put in peroba bark, it goes wonderfully well. You can have a plant which grows well in certain substrate and in some other, it doesn't. Some orchids grow well in piassaba. Another example, the sphagnum moss is great substrate, has a kind of antibiotic, decomposes very fast lasting less than tree fern fiber and. Trees bark rich in resin are bad because the resin doesn't allow the bacteria growth.
For example, I've done a mixture: wood, sphagnum moss, tree fern fiber and sand. Some plants grow very well but it can't be used for all.
I've never measured the humus acid level but it shouldn't be negligible because there is the decomposition of wood, sphagnum moss. There is açai'nut, the decay is too much fast, there is the natural coconut bark.
Do you know any orchid which doesn't go well in tree fern fiber? I don't.
You can say that it is not that well in tree fern fiber, it goes better in other substrate. But, finally, you can put every orchid in tree fern fiber and it will grow.
To reasoning in universal terms, for every kind of plant, not to referring to specific plant but for all, it is very hard, it doesn't exist yet.
For who runs a commercial nursery, the problem is serious.

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by Maria Esmeralda Soares Payão Damatté

Text extract from the Associate Professorship thesis of Prof. Esmeralda Payão Dematée, of the Horticultural Department of the Faculdade de Ciências Agrárias de Jaboticabal, Federal University of São Paulo (UNESP) (1992)

In Brazil, the tree fern fiber has been explored in prejudice of the Serra do Mar flora, it is extracted in big amount, from the species that, besides not to be replanted in a big extent, grow very slowly.

The true tree fern, Dicksonia selowiana (Presl.) Hook, is already rare so, nowadays the extraction is made from Cyathea shanschin Mart. Since 1990, the Brazilian laws limit the tree fern cut but, although it is doing inside the established limits, the product remains still intensively commercialized in inside Brazil and international market.

On the other hand, the orchids cultivation is important for two raisons, first because the species, in the wild, are threatened by extinction due to the destruction of their habitats and, secondly, because the commercial interest involving the sale.
As a result, the studies concerning the materials that can substitute the tree fern fiber as a substrate must be done, contributing for protecting, at the same time, the species which supply it and the Orchidaceae species.

Without a firm and well ventilated substrate which provides the settlement, the growth and the activities of the roots, orchids can't absorb water and nutrients needed. Although there are many adequate material, the choice is restrained by the availability in reasonable price and by the facility in obtaining it. The basic qualities of a good substrate must be: availability, good price, easy to deal with, able to maintain the plant firmly, longevity (it should last from 4 to 6 years), firmness, lack of toxicity and good ventilation.

The tree fern fiber presents all those qualities besides to be rich in nutrients and is considered, until now, as the ideal substrate for epiphytic orchids.

In the Northeast of Brazil, the coconut bark (Cocos nucifera L) has been used in orchid cultivation since the last century and the coxim, made from this bark, is a semi-industrialized pressed product forming small cubes, logs and slabs. It is a material which seems to be promising and can become an important product for the Northeast economy having as raw material-prima the industrial residues from the factories of coconuts fibers. The aggregation of this residue was obtained by Augusto Ferreira. With this aggregation, the inconveniences of the natural coconut bark have been eliminated and he has obtained a material without addictive, strongly hydrophilic which can become the tree fern fiber substitute. Having long lasting durability, it provides a good growth and good blooming, also supplies nutrients to the plants exempting the fertilization. According to the producer, it doesn't alkalize when decomposed and stabilize its pH at about 5,2 to 5,3, presenting a medium pH at about 5,53.

This study has been done during 36 months, having Dendrobium nobile Lindl as a test-plant. The experiences have been realized in 50% shade plant houses made of laths, in Jaboticabal, São Paulo.

The purposes were:

- Characterize the materials of vegetal origins used as substrate for epiphytic orchids concerning the physical properties (color, texture, density, water lost and structures alterations in relation to time) and chemical (pH and nutrients concentration) ;

- Comparing Dendrobium nobile development in different studied substrates having the tree fern fiber as witness.

- Recommend the adequate material to replace the tree fern fiber.

The following substrates have been utilized:

1- Tree fern fiber (as witness);

2- Coxim;

3- Eucalyptus grandis bark;

4- Coxim (50%) mixed with Eucalyptus grandis bark(50%);

5- Coxim (70%) mixed with charcoal (30%)

6- Eucalyptus grandis bark (70%) mixed with charcoal (30%)

7- Coxim (38%) mixed with Eucalyptus grandis bark (35%) and charcoal (30%)

The containers with the studied substrates have been maintained in the same environment conditions and periodically many tests have been executed in order to do different verifications: Water lost and alteration in original structure in relation to time, pH, the concentration of macro and micro-nutrients, among others. Among the studied material, the coxim bears most resemblance to tree fern fibers and this likeness is interesting to the point of commercial view because of the aesthetic effect with which the customer is used to. Regarding to the global density which reflexes on the pot weight, no substrate is more advantageous than tree fern fiber while the coxim weight is a problem to hang pots and to transport them. On the other hand, the weight of small cubs helps to fix the plant in the pot and replant becomes easier and faster.

The results obtained with the coxim confirmed that, at the first, there is no too much water retention but with the use, the material acquires the capacity of retaining humid. Coxim was the substrate which remains for more time inside the suitable levels of pH, between 4,8 and 5,5, considered as ideal for orchids cultivation. In the mixture of coxim and charcoal, the pH level remains suitable for a more restrict period. The pH of the other substrates weren't inside those suitable levels. Concerning the nutrients, when new, the coxim distinguished itself, overcoming the new tree fern fiber in the concentration of phosphorus, calcium, magnesium, boron, magnesium, molybdenum and mainly, potassium, The most big problem presented by the Eucalyptus bark was the alteration of its structure and after a certain time of using, it becomes an inadequate substrate for the orchids cultivation because of lost of porosity which is indispensable for the good aeration. In this aspect, the advantages of coxim and charcoal were showed clearly.

The charcoal, although considered as a inert material, presented significant concentration of nutrients except for phosphorus. From this study, it has been concluded that crushed Eucalyptus grandis bark, without mixture, is not appropriated as a substrate for epiphytic orchids. Among the substrates studied, the coxim without mixture is the one which assemble more advantages for substituting the tree fern fibers.

It presented the following advantages regarding to the other proposed substrates.

- It looks like tree fern fiber;

- It is easy to deal with;

- The aeration and drainage are good;

- Big capacity of retaining humidity after being used for some time;

- Durability;

- pH suitable;

- Adequate nutrients compositions after a period of leaching

On the other hand, it presented the following disadvantages:

- It presented a big density which arises the transport costs and makes the pots very heavy.

- It retained little humidity when new making necessary to let it immerses for a period before its utilization (the coxim has already suffered some modification for increasing its capacity to retain water).

- It presented a high initial level of nutrients which can disadvantageous for the orchid.

- It is still an expensive material and the availability is restraint.

The cost is a factor of big importance that should be considered to choose the substrate.

The coxim, in the south of Brazil, is more expensive because of the transport since it is made in Recife and need to be ordered to the producer but this is a situation which is modified as time goes by.

Eucalyptus bark can be free obtained. In order to reduce costs, the coxim can be mixed to charcoal, crushed Eucalyptus grandis bark or both materials although those mixtures were inferior when compared with the other advantages above. Eucalyptus bark can be got free and the charcoal is sold a cheap price. But we must say that it is made, very often, from the cut of the trees which occur en native woods, provoking its devastation.

On the other hand, the tree fern fibers price, which substitution is proposed, increased in the proportion the material become rare.

It is necessary to do previous tests with the species to be cultivated although the results obtained with Dendrobium nobile have been satisfactory.

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Waldemar Schelliga

Amateur orchid grower for more than 30 years,
has orchid greenhouses in Rio de Janeiro and in Petrópolis.

I've been using coxim since 5 years ago. I am doing it in a gradually way. For each container I open, I divide into two cuts, I put one in coxim and the other in tree fern fiber.
I should say that the results obtained are identical. Concerning the fertilizers, as far as I am concerned, I don't see any difference, I apply the same for both substrates. I apply a granulated mixture of bone dust, Ricinus communis' bran and ashes from wood , 3 times a years, in September, January and April, not applying during the winter. There is no other complement.
First, I sink the pot into the water, I put the mixture, than I superficially water in order to permit the fertilizer works into the substrate and doesn't go away during this first watering. Nowadays, 20% of my plants are cultivated in cubes of coxim.
The advantage of this substrate is the aeration of the roots. The cubes can not be put in organized way, they should be throw freely, not compressed, allowing the suitable ventilation of the radicular system. I am just talking the coxim cubes, as a matter of fact, this aeration doesn't happen with the granulated so I don't think it works in this kind of presentation.
I can see another advantage. When we have to do the reppoting, when the decomposition starts, it is very easy to clean the roots. It can be completely eliminated with the water. They become clean and we cant put the new cubes among the roots, in the empty spaces, it is extremely simple. I've just done it with a Vanda in a wood basket.
It is a long lasting substrate and can be used for 5 years, it doesn't rot practically. It takes years to decompose and maintains the pH level at 5,4 until the end and in this way, it is better than tree fern fibers.
And the disadvantages can be perfectly overcome.
First of all, the coxim must be soaked for, at least, 8 days, changing the water daily to eliminate the tannin which exists in the coconut bark. The tannin is highly harmful to the roots but after washing the coxim will be clean completely and adequate to orchids cultivation, humid without acidity.
On the other hand, although the tree fern fiber doesn't need to be soaked for long time, I have the same precaution. First of all, I sieve it to take off the powder and then I wash carefully to eliminate it totally. The disadvantage of the tree fern fiber is exactly this, the dust retains too much humidity and makes the roots decay. Coxim doesn't has this disadvantage.
Concerning the use, we must learn how to deal with it, the away of putting the plant in the pot is different. The tree fern fiber, for example, hold better the plant which stays more sustained. With coxim, we must hold it better in order to fix well the plant. It is a little more hard. I use the side small holes to tie it. I put the plant back close to the pot wall, pass a line through the closest hole, pass it around the plant, then through the same hole and tie it around the pot. I do the same thing with one of the other hole and if it is a hang pot, the wire also helps holding it.
I know there are some other methods but, in my opinion, this one is good. As I said, the disadvantages are perfectly overcome and don't discourage the use of coxim.
And about the humidity retention, it is good provides you maintain the regularity of the watering in order to keep it always humid. The coxim claims for a little bit different watering, it needs care. The tree fern fiber, for example, need to be completely dried out before watering again but the coxim needs to be always humid, the surface dries out very quickly. This is why, I don't think it is a good substrate for orchids with delicate roots like Miltonia, Oncidium and so on... In this case, I prefer to use tree barks like cork, for example.
About the nutrition, as far as I am concerned, coxim is so efficient as tree fern fiber, both require an adequate feeding. As I've already said, I apply the same fertilizer system for both substrates and I get the same results.
I just use the cubes. The granulated becomes too much compact retaining too much humidity. While the granulated is harmful because the ventilation is not good , in slabs, it is quite the contrary, they dry out very quickly but also damaging the roots. It is very complicated to keep them humid. To me, coxim means cubes.
About the options we have, I think that the cork bark, as I said, is very good for Oncidium. There are some other completely neutral, for example, pebbles, piassaba and requires much more fertilizer.
Pebble retains nothing of humidity, piassaba retains a little, both are insufficient , the humidity must be uniform.
Piassaba has an interesting characteristic, it wears up but it doesn't decompose, it is used in the Northeast of Brazil to do chains cables for the boats. Pine bark makes me worried because here, it not disinfected and can bring diseases. It is used in United States but there it is sterilized.
I consider coxim is perfectly adequate and I have been obtained good results with it. Except for the orchids with delicate roots, in my opinion it is, until now, the ideal substitute for tree fern fiber. If I must change all the substrate in my nurseries, I will change for coxim but I as long as I have tree fern fiber, I keep in using it and doing as I am doing until now, the most part of the plants in it, another part in coxim.

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Roberto Agnes

Associate and technical director ofOrquidário Aranda

Here, at Aranda, nowadays we use basically tree fern fiber alone or mixed to pebbles in many proportion, depending on the genus.
With Cattleya, the proportion is 1/3 of pebbles for 2/3 of tree fern fiber, with Cymbidium, is 50 to 50. For orchids with delicate roots, we just use tree fern fiber. With Vandaceous, we use nothing, just tie them to the hanging wood basket.
I would like to say that I am approaching the subject by the point of view of a big commercial orchid grower because for the small collections, the control is almost individual for each pot is easy and can be done, there is no problem to have the collection divided into many kinds of substrates and containers. But, in our case, as well as the other commercial nurseries, we need uniformity on the staging. With more than 150.000 adults plants, without counting the seedlings, there is no possibility to do differentiated watering.
Because of this and for many other reasons, in Terezópolis, all of our plants, except for Vandaceous and Oncidium, are planted in plastic containers.
We have already done experiences in alternative substrates and all of them can be considered disastrous. We tried to use only pebbles, it didn't work, it dries out excessively. We tried Acacia bark, a disaster. Due to low level of lignin and as a leguminous plant, it is too soft, retains too much water and hasn't enough oxygenation, the decomposing is processed in a high speed. Some times, in 6 months, it becomes a solid mass.
We have done a mixture formed by cork bark, small balls of polystyrene and sphagnum moss. First, if works well but then the chemical composition used in cork changed and didn't work any more.
The cork sold is the residue of the cork stopper fabrication so it receives a chemical treatment inappropriate to orchid cultivation. Besides, it is a very expensive material. Solved the problem the control chemical products, it can work with a small collection but in a large extent, it wouldn't be economically possible.
Nowadays we have at our disposal the sphagnum moss from Chile so good as New Zealand's, which doesn't crumble as our. It is an excellent substrate but not for all orchids. For Masdevallia and some orchids with delicate roots is terrific but its decomposing is very fast and have to be replaced every year.
It is excellent to recover plants and can be used in community pots. The watering control must be very rigid. Another problem is the very slowly growth, there is no way to be replace at short date. It becomes a very expensive substrate, not possible to a large extent.
However, concerning this question, many experiences are being done or had already done. In USA, far bark is very used, comes from California region. To use the bark from resinous trees, it is necessary to eliminate the resin they have. It seems that in the South of Brazil, it has been used and works very well but it is still very expensive. I've seen good results with this kind of cultivation.
Piassaba is another substrate which seemed to be very interesting but the continuous used proved that it doesn't work well. It has many inconveniences, it doesn't retain humidity, causes skin problems, it is very hard to touch, hurts manipulator fingers and hand. It is easy to manipulate 1 or 2 pots but you can imagine manipulate 12.000 with so hard product which doesn't permit the use of gloves to protect the hands. The glove should be very thick to prevent the fiber passes through it.
I can't talk about coxim because Aranda is not using yet. It is a very expensive substrate.
After all, the tree fern fiber is the best alternative but organic materials will disappear and that is why they become more and more expensive.
The organic substrates are or will become impracticable for a big nursery. It is universal. Australia or New Zealand, where there are cultivation with organic substrates from native species, are facing the same problems.
So, in my opinion, soon or later, in a moment, we will start using the inorganic substrates. We'll take the same way United States and Europe got in. In this places, inorganic substrates like rock-wool and floral (derived from petroleum) are use. They worked very well if used in well controlled collections, very well organized. Inappropriate to out-door cultivation because they practically assimilate all substances, water, chemical residues of fertilizer, residues of medicines applied. The control of this excess must be rigid. Before applying fertilizer, the mineral salts presence must be carefully measured.
Who has succeeded in regulating all those controls, like the greenhouses orchids in Holland, has an excellent cultivation. Before adopting this method, we have to do some adaptations and researches in order to verify how the plant will react with the combination of tropic hotness, high humidity and accumulation of saline water.
We have to consider the alteration of the plant capacity to assimilate mineral salts and the alteration of chemical composition of those salts. Finally, how those substrates act and react under different conditions.
There is many differences between European and American climate and our and there are a rigid control of the temperature inside their nurseries. In low temperature, the metabolism is slow, has less power of assimilation. In higher temperature, it modifies but just until a certain point because above 27o C, the plant metabolize slowly again.
All those points should be studied before adopting those substrates. I have being observed this phenomena with Phalaenopsis, although there are warm climate plants, the excess of hotness affects their development. During the hot period of the summer, their leaves become softer. How they will react in a new substrate which retains more water?
Finally, In my opinion, we can't run away. In the future, we will have to use inorganic substrates because the organic ones will disappear.

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Nelson Barbosa Machado Neto

I am an agronomist and work with the genetics and physiology of the plants. I am also an orchid grower for 15 years although I have gone away from this activity for long time.
In my journeys into my country's woods, I could observe many orchids species which, always (except for the terrestrial and paludicole), have their roots exposed, that is, visible and many times covered with 'dust' as it is commonly said.
I start on this thought, if the orchids have part of the velamen covered with humus, it can't be completely harmful. I am thinking about meters and meters of confined roots inside pots, filled with tree fern fiber or any substrate which decomposes. Of course, the velamen will be covered by the humus, causing some oxygen deficiency to the radicular tissue and encouraging an anaerobe environment as it has already said.
Taking the word substrate into account, I think that it is just a support and doesn't help the nutrition. The nutrients to any cultivated orchid should be added periodically, as it happens in nature. The wind and the rain take charge of bringing those nutrients from other parts of the support to be intercepted by the spread roots of the epiphytic or rupicolous.
So, I should consider as a "bonus" any nutrient which can exists in any substrate, tree fern fiber, sphagnum, coconut bark, coxim, pebbles and much more.
The species preservation is a great subject which deserves and must be taken into account but I guess that it is not only the individual orchid growers who are using this fiber.
The big and medium greenhouses, Brazilian and foreigner, bear heavier responsibility than the small ones, although I don't have data to confirm this assertion (See the IBGE's site ).
I would like to think that the forum should discuss about the extinction of genetic stocks and species, even if it doesn't have commercial value at present. Species like Laelia alaori, Cattleya velutina and Cattleya kerri and some others which are showed in international catalogues as "exploited species until their virtual destruction, now available..."
Those facts should be considered instead of discussing the salts retention and quality of the substrates
The truth is that for the small orchid growers, the lack of a practical substrate will be an obstacle but I imagine for the big ones.
By the way, when will us discuss about the next to get in this list, the sphagnum???

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Greg Alikas

Photographer and orchid grower.
Responsible by the sites
The Orchid Photo Page and The O Zone

You are certainly providing a service to the global orchid community by bringing the crisis of the tree fern's threatened survival to the forefront.
In some ways it is a problem for orchid growers and in some ways it is not.
If a whole collection or commercial enterprise is geared to using tree fern as a potting media then having to adjust cultural practices to a new material is a problem.
However, as you are aware, epiphytic orchids will grow in or on almost anything that is not objectionable to them, the potting material is merely a support. I have seen orchids grown in glass marbles in styrofoam pots, Vandas grown in old beef bones, Oncidiums grown on slabs of styrofoam, Encyclias grown on cow skulls, one of the healthiest C. aclandiae I ever saw was growing on the outside of a clay pot.
I think the loss of tree fern as a potting material is more of a loss to commercial growers with a profit motive and thousands of plants than individuals with a few hundred orchids who can, and usually do, experiment with other potting materials.
In the US, tree fern has been expensive and occasionally hard to find for several years. Many growers have already found other media. As is mentioned at your forum, many growers here use fir bark which is relatively inexpensive and readily available.
Indeed, along with sphagnum moss, it is probably the most frequently used material for growing orchids, especially for growers in temperate areas. Here in South Florida it deteriorates far too rapidly for our use.
A few years ago we began moving all our orchids out of tree fern and into lava rock, this was the best thing we ever did. Our move to lava rock was a cultural move, not a response to dwindling tree fern supplies. We grow our mixed collection of 700 plants in an open shade house in South Florida where they are subjected to extended rainy spells and warm temperatures.
Although tree fern had been a reliable media for us for decades, the inorganic material is proving to be superior. I should add here that we use sphagnum for Phals and some species grown in baskets and mounts for species that need them.

The advantages of inorganic media are: There are only one or two possible drawbacks:
photo by Greg Alikas
Lava Rock (left) and Aliflor (right)
There are several of these inorganic aggregates; Solite, Aliflor and Lava Rock all share similar properties which differ from expanded clay in having tiny pits in the surface to retain moisture. As I mentioned earlier, orchids can be grown in almost any simpatico material providing that cultural practices are adjusted accordingly.

In closing let me offer my Rule #1:
Before moving your whole orchid collection into a new potting medium experiment with a small number of orchids (preferably duplicates) in that growing medium for at least one year or a full change of seasons whichever comes first.

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Ernie Anderson

Dear Sergio,
I could not help but notice the disappointment in your editorial of News #5 and I share it.
You must remember however that you are doing a great deal of service for the conservation movement in all of your efforts. You have a fantastic web page that is accessed by many people and is growing.
What an opportunity for a voice to be heard!
Also your first request for the input on the subject of tree fern sowed the seed. The germination and maturation of the seed will take time, but you have started the process only if you have made people aware of the use of the material and it's impact.
Return to the subject in future issues and I think you may be surprised.
Another reason I did not respond to your first call was embarrassment. I am not in the league of your experienced growers such as the gentleman in News#4 who had been in the orchid field for many years. It was difficult to respond with my limited knowledge when you have such informative and experienced growers in Brazil.
Here in British Columbia, Canada, we are called "the Brazil of the North" by the media in both North America and Europe.
We have old growth forests which are being harvested at alarming rates. We export logs to Asia, which means we do not even get the processing jobs from our forests (we are exporting jobs along with the raw material).
We have temperate rain forests of incredible beauty, and here the battle is the same one you are fighting. Sustainability.
When I started growing orchids, the reference material recommended bark as a potting medium for many species I had. Then an article in the American Orchid Soc. magazine discussed the use of peat mixes (Growing in Mud was the article). We changed our medium and it is more stable for some plants.
I started an article to you after that but in reflection I thought about the product. A lot of the peat comes from Alberta, Canada. The areas harvested are usually wetlands, and the areas are strip mined in the process. Bogs and wetlands are under pressure in all areas due to the inference that they are "wasted areas" when in fact they are the "lungs" of the earth. So now we use it for limited applications, i.e. the phaleanopsis that my wife grows, some large cattleya pots. But my thinking lately as I mused over your original article has been on available mediums.
We are all looking for the proverbial silver bullet, a medium for all uses. Maybe we are asking for too much, and a return to mixed mediums is in order, dependent upon the species.
I have a friend here who was a nurseryman in Hawaii. He exported plants to many places in the world, and was always a "middle man". Through this he has gained considerable knowledge, but it does not readily show. He now imports orchids, brings them into spike and sells them through flower auctions or to other outlets. He can bring plants into spike in amazing speed, and the plants look healthy and clean, like Aranda's. He develops mediums for his use, and the one he uses for what I am interested in, the Oncidium Alliance is interesting.
As stated, we live near rain forests. There is abundant and sustainable forest moss. It grows in great matts on decaying logs and forest floors. When we harvest, we take only portions of the growth, and it regenerates in about a year. The moss is long strand forest moss, probably Claopodium Crispifolium or of the Heterocladium group. It can be used fresh as I do, or it can be harvested and stored to dry as my friend does.
The process then involves "combing" the moss. My friend uses a machine to process the matts which separates the individual strands fluffing up the moss in the process. Sponge Rock (agricultural grade perlite, a heat expanded sand) is added with water to it and the mixture is then drained and stored. Because I am a hobby grower, I do my fluffing and mixture by hand, but the end result is quite similar. The plants take to it extremely well. It is difficult to overwater (of benefit to beginners) and does not store fertilizers excessively. It is neutral on the Ph scale, breaks down slowly, and is relatively easy to repot/replace.
Mediums maybe should be chosen on the 3 S's (like the 3 R's), primarily sustainability of supply, secondarily simplicity of use in both potting and maintenance, and last but not least, suitability, the response of the plant to the medium.

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Luiz A. Menéndez

(Argentinean orchid grower and researcher of Oncidium genus )

I really regret the lack of interest in looking for an alternative substrate for cultivation in order to avoid using tree fern fiber.
Some friends and I have decided for reducing at the utmost the using of this fiber because we noticed that as time goes, the orchids stop to grow and weaken due to the decomposition and the acidity level. To solve this problem, the orchid should be reppoted in new fiber.
A long time ago, we decided not only to get rid of our anti-esthetics containers but also to use a small quantity of tree fern, just a layer up to about 1cm thick, put it under the cut roots in order to provide a humidity support for the new roots and then we tied them to the trunks.
We settled all orchids in trunks which are hold by the walls. We can see, day by day, how the roots leave the tree fern, reach the wood and then the wall. Many plants grip to the painted walls and bloom very well. Like, for example, Vandas. I, particularly, have done it, in the last months, with Cattleyas and Phalaenopsis, between others, I put the naked roots directly on the logs and over them, a little, just a little quantity of moss. I noticed, at the same time, a young and strong rooting. And in this ways, we abolished the xaxim.
As you can see, at the first sight, it is not ecological because I am using as an alternative, chopped trunks of tough wood trees. So since long time ago, I did not buy xaxim.
That is an alternative solution to induce the development of the plants. They will, as time passes, get the walls on such a way that will never need to be re-planted. Finally, save this cultivation medium , replacing it by the masonry and fertilizer will be, I guess, a little contribution to stop, partly, the trees and xaxim's cut . Our first aim was not to "save the xaxim, we were , as I said, looking for a better substrate for our plants.
Nowadays, by the comments you have done in the site "Brazilian Orchids", I took note of the danger of the species and I am engaged. Do not use xaxim!

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Helio E. Marodin

(sales manager of Coxim in Porto Alegre, state of Rio Grande do Sul - Brazil).

Due to the big boom of the commercialization of samambaias (polypodie) which swept the country, since the eighty years, the exploitation and commercialization of tree fern is forbidden in the state of Rio Grande do Sul (Brazil).
Because of the long time required for its regeneration, xaxim (tree fern) is seriously endangered. We, all orchid growers of Rio Grande do Sul, were deeply affected because the xaxim was, traditionally, the substrate used to cultivate orchids, perhaps the only one. Even then, many pioneers tried some alternative solutions like to cultivate in peroba (Aspidosperma polyneuron) bark, pine bark pure, mixed to sphagnum, sand or something else.
In fact, all those pot medium had serious problems of rooting, decomposition and aeration. As the resin makes the pine bark impermeable and doesn't allow the retention of water, I always had troubles with dehydration of my plants cultivated in this substrate. The rooting, the development of the plants, the grown were poor, bringing diseases, fungus and all kind of opportunist pests.
When my friend, Doctor Alfeu Cardoso, brought from Recife some coxim plaques, my motivation was not a great deal because of the price some favorable experiences with peroba bark. Although this bark is the best substrate I tried, it became impracticable because of its scarcity and I decided to try the cubes of coxim gave me by Aldomar Sander. So, although having a dislike due to the former failures with alternative substrates, I planted some divisions of inferior plants of Cattleya intermedia, Laelia purpurata and Cattleya leopoldii.
At the beginning I noticed that the tips of the new roots were burnt what some people blamed on the excessive presence of tannin in the material. However, I didn't believe in this story and tried another solution. As the substrate stays free inside the container, I decided to support the plants with stake and tie them in order to avoid the plants shake with the wind.
Soon the results appear. The roots grow well holding the cubes firmly. The pseudobulbs became vigorous, the leaves thicker and the blooming stronger. The strength of the plant was in a such way that some new shoots were so "fat" that seemed to have larvae inside. Soon I realized that, when I took the plants from the container, even the old roots grew out and the health's plant was excellent. Coxim offers an amazing rooting with white velamen, firmly and roots ramification. Good roots produce vigorous pseudobulbs and thicker leaves.
As the substrate is presented in cubes, there is a empty room between them, as a result, we have what we were always looking for and we really didn't find, even with xaxim: ROOTS AERATION.
Of course, all those thing should be carried on with adequate watering and luminosity for each cultivated species. I, practically, do not fertilize my plants because coxim furnishes almost all nutrients required. Nowadays, 4 years later, the first containers filled with coxim start to present signals of deterioration, with moss intensively growing in the surface. However, the substrate replace has not being traumatic because the coxim crumble and is easily taking away from the mass of the roots. The cubes which do not crumble can be taking away without effort or harming the roots, although you should be careful. The recuperation of the reppoted plants is normal, without wilting.
Some orchids growers like Dirceu Mendo and Zacarias Sulepa used and are still using coxim, having the same results. Honório Trombini had also used this substrate. However some companions did not get the same results. Why?
There is no secret to cultivate with coxim but there are some rules to be respected:
1) I put my plants in plastic containers because in my nursery the containers tend to dry out very quickly. With plastic pots, besides the more beautiful looking, there is the advantage of conserving the humidity;
2) Before using the coxim, I soak all material in water for, at least, a week, changing the water every day in order to reduce the presence of tannin;
3) Keep the coxim moist mainly during the first month of plantation in order to avoid the plant dehydration;
4) I feed very little with fertilizer rich in Nitrogen and poor in P and K because coxim is rich in Phosphorus and Potassium.
Nowadays, I am cultivating besides the Cattleyas intermedia, practically almost all kind of orchids and I just do not have the same results with old Laelia purpurata, perhaps due to the long poisoning and the weakness of the plants constantly cut and divided until become almost seedling, largely infected for all kind of bacterial and fungus disease, even virus.
However, the Laelia purpurata's seedling are now blooming with 6 years, the plants are strong and vigorous and the flowers are as expected. My Laelia purpurata seedlings used to take 10 t0 12 years to bloom when cultivated in tree fern.
The hybrids produce strong pseudobulbs and intense blooming.
Even the Paphiopedilum species I cultivate in deteriorated coxim which I take from the reppoted plants. The results are great and cultivate Paphiopedilum in Porto Alegre, without green house is not a big deal. The plantlets are becoming clumps and the Phalaenopsis are also loving the substrate, not our coldness.

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