Soil For Orchids: one of the major hindrances in orchid Culture
Hello guys! I now come with a technical post on a topic that is extremely important and that is often the key to many of the problems we experience in growing our orchids.
Due to the great importance of this theme, it will be divided into 2 parts so that reading is not tiring, this first part introductory to explain what the substrate, its qualities and problems, its types and functions; in the second part will be approached the question related to the problems that the bad substrates can cause; the difficulties of obtaining good substrates and the possible solutions that can be useful to cure or alleviate the problems.Without further ado, let’s get down to business.
As you can see from this image, this is a mixed substrate, which is the base of charcoal, hard shell of coconut, bark of macadamia and bark of peroba and it has a certain granulometry (size of the pieces) such that it is suitable for the root gauge, so that it will satisfy the need of the plant in question that will be placed in it and of breaking it has a good drainage and aeration, since there are several large empty spaces with air (pores) inside the container with it and note that it has no soil or any other material that looks like powder or fine grains.
Well this has all been said so we can understand what the main and almost exclusive (or should be) function of substrates for orchids, so let’s now define in a concise way their functions:
- fixing the roots of the plant (main function) guaranteeing plant support;
- allow adequate respiration of the roots;
- allow proper root development;
- hold a minimum of humidity without disturbing the breathing of the roots (desirable);
- mineral nutrition of the roots (little important, due to the model of fertilization used).
So folks, these are the functions of the substrate, or they should be, but often because of the poor quality of the materials is not possible and this is much more common than we think, but this subject will be addressed in the second part.
Now speaking a little of each function in more detail we can say the following:
1. The root fixation and support of the plant is quite obvious and easy to understand, because if a substrate can not keep the plant firmly in the pot, it is no longer good for cultivation, because an orchid that can not fix its roots the ones that like to be totally aerial) will hardly be able to develop well and many problems will occur, so in order for a substrate to be good it must guarantee the proper fixation of the roots, so it is also fundamental that it has a granulometry that is adequate to the caliber of the roots that will attach to it being neither too thick nor too thin. In addition, it must have a certain roughness on its surface that can facilitate the adhesion of the roots giving a higher quality to the substrate; 2. The question of allowing adequate respiration of the roots concerns their porosity. Substrates with larger pores and a larger number of pores will allow better aeration which will allow a correct respiration of the roots, while those with a very fine material, such as powder and very small grains, that compact easily are already more problematic, being able to prevent a correct aeration and breathing of the roots bringing problems;3. the issue of root development is linked both to the question of its porosity and to the matter of the material used, since materials that release toxic substances, for example tannins, commonly found in plant peels such as pine, macadamia, among others can slow the growth of the roots and even kill them, which greatly delay the growth of the plant and may even lead to death. However, in relation to the toxic substances it is possible to do the treatment to remove them making the substrate suitable for use, but as for the porosity if the substrate is compacted with very small pores, there is not much to do. The PH of the substrate is another factor that determines or not the good development of the roots, because it is linked to the delicate balance of the availability of various minerals and also to the activation and deactivation of some toxic substances, and PH is usually between 5.5 and 6.5, although there are plants that prefer a more alkaline substrate and other more acid, but for most plants it is in this range that it allows adequate availability of the minerals. Fortunately the PH can also be adjusted and corrected at the time of substrate assembly and it is also worth remembering that as the substrate grows older the PH will become more acidic and one of the consequences of this is that the plant starts to develop less , have a problem of nutritional deficiency and root death; although there are plants that prefer more alkaline substratum and others support more acid, but for most plants it is in this range that is the one that allows an adequate availability of the minerals. Fortunately the PH can also be adjusted and corrected at the time of substrate assembly and it is also worth remembering that as the substrate grows older the PH will become more acidic and one of the consequences of this is that the plant starts to develop less , have a problem of nutritional deficiency and root death; although there are plants that prefer more alkaline substratum and others support more acid, but for most plants it is in this range that is the one that allows an adequate availability of the minerals. Fortunately the PH can also be adjusted and corrected at the time of substrate assembly and it is also worth remembering that as the substrate grows older the PH will become more acidic and one of the consequences of this is that the plant starts to develop less , have a problem of nutritional deficiency and root death;4. Holding a minimum of moisture without compromising root respiration is very desirable because very dry substrates require more intensive watering and at shorter intervals to supply the plants, but substrates that retain a lot of moisture have a greater tendency to pack and bring problems, and it is even easier to work with the dry substrate than with a high moisture content. This question of moisture retention is basically linked to the question of porosity and the type of material. As for porosity there are the so-called macropores, which are the large spaces between the pieces of the substrate and they are responsible for the aeration of the substrate and there are the micropores, which in clean substrates based on barks and stones or inert materials is practically nonexistent, but in fibrous materials, such as sfagnum, coconut fiber and xaxim are more common and are responsible for the retention of moisture and the phenomenon of capillarity, which causes water to rise through the substrate and why these substrates have a greater capacity for moisture retention, which on the one hand is good , but on the other hand it greatly increases the chances of compaction of this material hindering the respiration and advancement of the roots.The type of material is related to its capacity to absorb and adsorb * water, and this capacity is also related to the age of this material, and older materials have a greater capacity to absorb and absorb water.Absorption and adsorption are also linked to natural porosity, which some types of materials may have. Note that here I speak of the porosity of the material itself and not of the pores which are the space between one piece and another. An example, is the expanded clay (kinasite) that is a very porous material, mainly micropores that retain moisture and still have the interior with several macropores that keeps its interior aerated, which also ensures that it is very light. Some materials can be oily, as is the case of Macadamia peels and some other seeds, which hinders or prevents the adsorption of water on its surface, making them very dry, but with the aging time and the degradation of this material adsorption is increasing. Due to the great complexity of this issue and the difficulty of finding a single material capable of satisfying the desired conditions is that the mixture of materials is sought, to find a middle ground that fulfills all the desirable functions for a good substrate;5. Mineral nutrition is not important in this case because as fertilization is a constant practice and is usually done with soluble fertilizers of immediate absorption, the substrates do not have the need to hold the minerals and in general also the materials used are very poor or practically inert, because works with non-decomposed green organic matter, such as vegetable peels and fibers that release little or no nutrient while intact, or work with inert and even synthetic materials such as styrofoam, crushed stone, expanded clay, among others. of the fertility characteristic of the substrate is not important or even null, but when speaking of truly terrestrial orchids the story already changes a bit,because it works with soil rich in stable decomposed organic matter and materials that increase the natural fertility of this substrate, but these are the exceptions.
Characteristics of materials:
Let’s go back to reading now then? Ok, let’s go to the characteristics of the materials that make up the substrates for orchids.
The most common substrates used are: sfagnum, treated pine bark, charcoal, granite or gneiss construction, styrofoam, expanded clay (kinasite), treated macadamia peel, bark bark, bark of peroba, the coconut of the açaí (regional), rock canga, fiber of coconut, coconut shell, among others several.
But what about the xaxim? Note that I mentioned a range of materials and I did not mention the xaxim because the xaxim, which was once the most used substrate in the past, is now being replaced, due to the fact that the fern that originates the xaxim fiber is threatened extinction and this is a prohibited substratum of extraction and commercialization at the moment, although there is still a lot of people using, collecting and commercializing, but that it is very clear here in this matter that everything related to the xaxim today is about extraction and illegal commerce, which will not be stimulated in this blog.
Personally after this listing of the materials we go to the characteristics that each one has and what makes them suitable substrates for the cultivation of epiphytic and often rupicolous orchids as well. The characteristics that are important for qualifying a substrate are:
- porosity of the material
- moisture retention
- weight (density)
- propensity to compaction
Finally with these characteristics we can now talk about each of the main materials used to explain their characteristics a little.
To begin with we go to our old fodder that is forbidden and should be avoided its use.
The xaxim that comes from the fern Dicksonia sellowiana is a material of the organic and fibrous type, removed from the stem of the fern and was and still is the darling of many orchids, due to the great initial response that the orchids have in this type of substrate, besides that it had an average durability around about 2 to 3 years in pot and in the form of plaques and pots and may have a slightly longer shelf life. However, with the ban it was gradually having to be replaced, as it began to be scarce in the market and very expensive, with that, other types of materials were used until you get good substrates, as you have today and due to certain higher characteristics of certain materials have been considered more for the negative characteristics of the xaxim, that is its great capacity of compaction, a high retention of humidity and suffocation of roots, when older and degraded and tendency to acidification, as it is decomposing, added to this the great difficulty of cleaning plants in xaxim for replanting. This is also a substrate of medium weight and poor in tannins and still with a certain natural fertility that guaranteed the minimum necessary for the plants to remain for a certain period, even without fertilization.
The next material is the pinus bark. This was widely spread after the ban on fiber and has proved to be a good, because it has a medium durability of 2 to 3 years, when the bark is of good quality; is a light substrate, has little moisture retention when new and moderate when older and is an organic peel type material. Another advantage is that it ensures good ventilation of the roots when of good quality, but as a disadvantage it is a material that has tannins, highly harmful to the roots and has a tendency to acidify as it ages. Another problem is its cut, because there is the bark of pinus in the form of fine scales, which is not interesting, because it compacts easily and has a degradation much faster than the other type which is the massive thick pieces that do not compact and have a much longer durability. As for tannins, what is done to make it fit for use is the treatment for the removal of tannins, which is quite simple, but will be subject to the second part of this matter.
Still in the pinus bark it can be found or prepared with different granulometries, which helps to meet all the possible caliber of orchid roots and it is also usually a component of the famous mix substrates, or simply a mixture of substrates.
The next material is sfagnum. The sfagnum is a dry, soft moss with great compaction capacity, which is good on the one hand, because it allows it a facility in replanting and in shaping bales or other more massive structures, great capacity of retention of humidity and a weight very light which leaves the vessels very light, but their compaction can also make it difficult to drain and ventilate the vessels and their durability is very low and in many cases less than 1 year. This substrate is widely used for the cultivation of new plants that have recently been exited from flasks, since it is a substratum that holds moisture well and plants are more sensitive at this stage. Very used also in cooler regions and with controlled environment, for the fact that it facilitates and reduces the cultivation, besides it under these conditions to have a greater useful life, however in hot regions and where the plants are subject to rain is a poor substrate causing problems quickly. Tannins and PH are usually no problem and when used in some blends such as styrofoam and planting on stumps of wood or even a live tree can help in the initial glue of the plant.
The next material is charcoal, that’s right, charcoal, the same used in barbecue, but new without use and preferably the same for agricultural use, but the barbecue also serves, although there are controversies. Coal is a very light material with undetermined durability, since it does not decompose in the short term and it has the characteristic also of accumulation of salts and substances with time, which is good on the one hand, but with time can be a periodic substrate washes are not done. It is also a dry material that does not retain almost any moisture, requiring frequent watering and tannins and PH is not usually a problem. It is little used in the pure form, but much used in the substrate mix because of its positive characteristics, Still in the coal, this one can be prepared with different granulometries, according to the gauge of the roots.
The next material is those derived from coconut. Look people there gives a lot of confusion, debates, but what most speak and affirm and in fact is, is that this material is very problematic. Coconut fiber came with an intention to revolutionize the market for substrates and pots instead of fennel. The marketing was great, the idea was good, without a doubt, but what happened was that such a cushion was a fiasco and it’s a fiasco! The cushion or simply the shredded coconut fiber was used to manufacture pots, sticks and boards, in addition to their loose use, but these have proved to be bad for the cultivation of orchids and also other plants, so much that it is not recommended by anyone. The problem with vases and coconut boards is that in their pressing and molding a type of glue is used to hold the fiber, but that with time this glue degrades and the fiber weakens releasing the bottom of the pots, not to mention that the fiber itself has a very short shelf life, a high tendency to salinize, making it useless for cultivation. Orchids in these materials at first go up well, but with little time the problems appear. Another coconut derivative is the coconut chip, which is coconut fiber cut into cubes, which is a slightly better material and has a slightly longer shelf life, but presents the same problems of salinity, rapid deterioration, high retention of humidity and compaction, being indicated its use only in mixtures and in small amount. Another coconut material is the shell of the coconut seed itself, that is the hard shell of the coconut and then this is a more durable material, allows good drainage and not compact, as the fibrous part. After speaking a little of the coconut we can conclude that this is an organic material that can be of the bark type or the fibrous type, depending on the part of the coconut. As for fiber, it has a great capacity of retention of humidity, salinity and tannin problems, requiring treatment before use, durability of less than 2 years, and may be less than 1 year. Large compaction capacity allowing to be molded and little recommended for cultivation. The fiber in the form of coconut chip has a slightly longer shelf life and initially holds less moisture, but over time the same problems of loose fiber appear. The non-compacted hard shell can be used in several sizes, including whole, after treatment becomes a good substrate and allows good aeration of the roots and is a drier substrate and with a durability of more than 2 years,
Britas, pebbles, hailstones and other stones:
The next material is crushed stones, rolled pebbles and pebbles. these materials are interesting, first because they are inert materials or with little chemical and biological activity and are inorganic and mineral in nature, derived from rocks with indeterminate durability, without or with very little presence of micropores, which make them substrates well dry, but due to its roughness has a certain capacity of moisture retention by the adsorption of water on its surface. They are materials that do not compact, are heavy and allow a spectacular adherence, aeration and root development, being considered one of the best materials for making substrates and even used in a pure way. The main disadvantage of gravel is actually the weight, but this can be solved when mixing other materials. There are several types of gravel, but here in Brazil the most common and also the best, because it is really inert is the grinding of granite and gneiss, igneous and metamorphic rocks, respectively. The pebble rolled from quartz and river stone or leftover sand from the sand sifting are also excellent, since this material is mostly composed of quartz which is also inert. There is also the famous canga stone, which is a ferruginous stone, originating from the regions rich in iron ore, places where the rupicolous laelia usually occurs, which vegetate in this type of rock and have a great need of iron. This rock by having a certain degree of weathering with iron being oxidized, what gives it its reddish coloration possesses a certain liberation of this mineral, important for the rupiculas and thus being very used in the formulation of the mix for this type of plant in particular. There is also the gravel originated from limestone rocks, but this material is not used for cultivation, in general, because it is a sedimentary rock, alkaline reaction, which alkalinizes the medium disrupting the balance of the availability of nutrients to the plant and making that it has serious problems related to micronutrients. Limestone is uncommon, but found in regions rich in this type of material, being little problem for most people and the difference of this for granite gravel is that it usually has a more uniform color and usually a dark gray. Limestone can be used in very small quantities only or even to agricultural limestone for plants that need more neutral substrates, such as Paphiopediluns, Phalaenopsis and also Catasetuns, but the amount is minimal and only a single application. There are several sizes of gravel, generally 1 and zero are the most used and the size varies according to the caliber of the root. Fine roots, such as Dendrobiuns and Oncidiuns the most recommended is the zero gravel. Thick roots the most recommended is the 1 and median roots the merge from scratch with the 1. as Dendrobiuns and Oncidiuns the most recommended is the zero gravel. Thick roots the most recommended is the 1 and median roots the merge from scratch with the 1. as Dendrobiuns and Oncidiuns the most recommended is the zero gravel. Thick roots the most recommended is the 1 and median roots the merge from scratch with the 1.
The next material is Styrofoam. Styrofoam is a synthetic, inert and extremely light organic material. It can be easily cut into various sizes and does not compact. It allows a good aeration and drainage of the substrate and has indeterminate durability. It allows a good fixation and adherence of the roots. Its major problem is to be too light to interfere with the fixation of the plant in the pot and the low capacity of moisture retention, but when mixed with other materials the problem disappears and can still be used as a background material for drainage and can be used as a base , next to gravel to fix the plant in the pot, since the tutors can be nailed to the bottom styrofoam and above a layer of gravel ends the guardian with the plant.
Bark of macadamia, baru, açaí coke, others:
The next materials are the barks of macadamia, baru, acai coquine, among others. These are the most recent materials and have been a great alternative, since they are organic materials, hard shell type, with a durability of more than 3 years and can reach 5 years or more, do not compact, allowing a great drainage and aeration of the roots , allow a great adhesion of the same and they have a fast drying, mainly when very new, because they are very oily, preventing that the water is retained in the surface of the substrate, however with the degradation of this oil the retention of humidity increases a little, but without running the risk of being exaggerated. They have medium weights which helps to balance the weight of the pot, when mixed with gravel, styrofoam and charcoal. The major problem with this material has been its use in raw form, because often there is a rest of pulp in the bark, especially in macadamia and this attracts rats and mockery. The mold, though it may frighten us, because we may think that the substrate has spoiled does not cause any harm and in time disappears, but the rats do! These are a big problem for orchids being a very destructive pest that besides being attracted to the pulp of macadamia also appreciates buds, roots, pseudobulbs and leaves of the orchids, being able to do a great devastation and then all care is little! Fortunately there is partially toasted macadamiae which eliminates the problem of attracting mice and maintains the great qualities of this substrate. The bark of Baru, the açaí coquinho are more regional substrates, however the bark of Baru has gradually gained space and maybe become more popular in the future. These substrates all require treatment for the removal of the tannin prior to use and their pH is in the range suitable for the plants. They are usually sold treated and mixed with charcoal and other materials, which becomes an excellent substrate option.
Expanded clay (kinasite):
The next material is expanded clay or kinasite. Expanded clay is an inorganic and clay-like material made from the baking and aeration of the clay, which makes the balls very light, hard and resistant with a lot of voids inside and a certain capacity of moisture retention , due to its micropores, yet it is a very fast drying substrate. It does not compact and has an indeterminate durability, besides being almost inert. is sold in various sizes and allows for good rooting, good drainage and ventilation of the roots. It is more used as a bottom drainage material, however some growers use as pure substrate or in mixture with other materials. Some people say that this material over time accumulates salts and gets high salinity, however with good washes this problem should be eliminated. In practice it is a little used material, even though it is not such a cheap material and still has a low yield compared to other materials.
Live woods, logs, plaques and tutors :
To close, the woods, trunks, boards and tutors live. In this case the substrates are actually wood slabs, stumps with bark and bark, and live trees. Not all woods are suitable for cultivation, but those that are indicated must have the characteristic of good natural durability, water resistance and low tannin content, allowing a good rooting. They should also be resistant to drills and termites. The woods can be used in a closed way, such as slats, rafters, three legs and other cuts or as trunks and branches with or without bark, depending on the species. The most suitable for the cultivation of orchids and those that have a good durability and allow a great rooting are: Bark and wood of the peroba, pine knot, field stump (sabiá), mainly with bark, coffee stump, wood of ipê, angelim, aroeira, among others. In the case of live trees several fruit trees are indicated, especially citrus, avocado and mango trees, when not too shaded are also good, annatto, Cajas, among others are also great options. Peeling trees are not suitable for growing.
The cultivation on plaques, stumps and live trees are the ways in which it approaches more than the orchid lives in its natural habitat, not to mention that the cultivation in plaques has a very special charm and helps to save space, besides that for certain plants that do not go well in the pot becomes the only or the best option.
Because it’s personal, these were the materials, but there are many others and maybe in the future there are others!
Let’s now take another quick break in the personal reading and give one more lazy, drink some water and rest a bit to go back to the last part of the post? Let’s go then…
Mixture of substrates. Mix:
We come back from the rest and now we will talk about the mix, or simply mix of materials.
The mix was the best way to prepare good substrates, using the various existing materials, so that they better take advantage of their qualities, compensating their disadvantages and as a final result obtaining that substrate that best meets the needs of the orchids .As for the preparation of the mix there is no mystery and there are a multitude of ways to do, each of which has its own technique for the preparation of mixtures, but an important tip is that materials that have a great retention of moisture and ease are used 10% down in the blend with preference given to the fast and medium drying materials. It is also important to maintain a balance in relation to the thickness of each material, avoiding to mix very coarse materials, with very fine materials. There are also ready-made commercial blends that are a hand on the wheel for those who are in no condition to do, or simply do not have the patience to prepare their own blend. Among the most favored mixtures of the cultivators are the mix of pinus bark + charcoal + coconut chip + gravel, or pinus + charcoal + gravel bark, or bark of pinus + charcoal + gravel + sfagnum, or bark of macadamia + gravel, etc.
Symptom of substrate aging and root distribution in substrate volume:
This last part of the matter concerns an important issue and we should learn to observe throughout the crop and this observation can save our plant and avoid major problems in our orchards. When we learn to identify the symptoms of the old substrate and interpret the arrangement of the roots within the volume of the substrate we gain a powerful weapon to improve the quality of our substrates, avoid unnecessary uses of toxic pesticides and greatly improve our cultivation, and now we will learn how to identify these symptoms and to understand the distribution of the roots.
The symptoms of aging of the substrate are varied and the best known are those directly attached to the substrate. Due to this, to be more didactic the posting the symptoms will be divided into two groups: direct and indirect symptoms.The direct symptoms are those directly linked to the substrate aspects, ie, visual aspects, smell, texture, structure and so on. These symptoms are the most easily understood and acknowledged by growers, for by looking at a vase and feeling that smell of wet earth we have already deduced that the substrate is old, but this is only one of the symptoms of degradation. Degradation of the substrate is a complex process, but at the end decomposed and stabilized organic matter is called humus, or we can also say, black earth. Such valuable material for terrestrial plants (including terrestrial orchids) is a disaster for the epiphytes and rupicolaria because it compacts itself, together with partially decomposed materials and disrupts the respiration of the roots, in addition to retaining much more moisture, which favors the appearance of slugs and snails and fungi that cause disease, in addition to killing the roots due to lack of air. Another type of direct symptom is the partial degradation of the bark, although it presents a new bark appearance by touching and tightening it if it breaks or crumbles easily, demonstrating that it already has a high degree of decay. Compaction is another very frequent and easy to recognize symptom, which is very common on substrates based on xaxim or sfagnum fiber, also on low quality substrates based on pine and coccus. Acidification is another direct symptom, but more difficult to visualize, because the effects of this acidity are only noticed in the plant with nutritional deficiencies. Another type of direct symptom is the partial degradation of the bark, although it presents a new bark appearance by touching and tightening it if it breaks or crumbles easily, demonstrating that it already has a high degree of decay. Compaction is another very frequent and easy to recognize symptom, which is very common on substrates based on xaxim or sfagnum fiber, also on low quality substrates based on pine and coccus. Acidification is another direct symptom, but more difficult to visualize, because the effects of this acidity are only noticed in the plant with nutritional deficiencies. Another type of direct symptom is the partial degradation of the bark, although it presents a new bark appearance by touching and tightening it if it breaks or crumbles easily, demonstrating that it already has a high degree of decay. Compaction is another very frequent and easy to recognize symptom, which is very common on substrates based on xaxim or sfagnum fiber, also on low quality substrates based on pine and coccus. Acidification is another direct symptom, but more difficult to visualize, because the effects of this acidity are only noticed in the plant with nutritional deficiencies. Compaction is another very frequent and easy to recognize symptom, which is very common on substrates based on xaxim or sfagnum fiber, also on low quality substrates based on pine and coccus. Acidification is another direct symptom, but more difficult to visualize, because the effects of this acidity are only noticed in the plant with nutritional deficiencies. Compaction is another very frequent and easy to recognize symptom, which is very common on substrates based on xaxim or sfagnum fiber, also on low quality substrates based on pine and coccus. Acidification is another direct symptom, but more difficult to visualize, because the effects of this acidity are only noticed in the plant with nutritional deficiencies. The substrates may not exhibit all of these symptoms described, depending on the material, but when a substrate is in a very advanced stage of deterioration, virtually all symptoms appear and your plant may be in trouble.Besides these direct symptoms there are indirect symptoms and these are very important to understand, since they already appear long before the substrate is with a high degree of deterioration and among the indirect symptoms we can mention the following: slight loss of vigor of the plant; appearance of snakes, snake lice and other decomposing organisms; reduction of the root canal.The mild loss of vigor of the plant is a symptom often overlooked, as it may also be linked to a failure of fertilization, environmental changes or great wear of repeated blooms and capsule growth, but loss of vigor because of a substrate , which already shows a certain degree of deterioration, is usually slow and progressive and begins with a subtle decrease of the new shoots that are slightly smaller than the previous ones, besides a certain decrease of the radicular mesh inside the vessels. This decrease in subtle vigor is already an indication of substrate pH changes and some other changes that are hampering root development and nutrient absorption and often when looking at the substrate is still looking good. Often this decrease in vigor does not occur, because the plant has many roots outside the pot that are not impaired by the substrate and thus ensures an adequate supply of nutrients to the plant. Other times this decrease in vigor occurs at the back, especially when the front is already outside the vessel with roots totally out and the back is inside the vessel and no longer with viable roots or with few roots. In addition to this situation when we observe that there are animals walking on the substrate, or even snake lice is a sign that this substrate is already beginning to deteriorate. These little walking animals are usually colloquets, which do not harm the plant, but indicate that the substrate is already deteriorating and may no longer be as good for the plant. These collo-
After knowing the symptoms of aging of the substrate we can ask a question: What is the best time to replant?Answer: It depends, but the most appropriate is that when noticing the first symptoms of aging, preferably the indirect ones, to be clever and once the plant in question is in its respective time of reconsidering to think about doing the replant, avoiding to let the substrate will deteriorate too much.
And speaking of personal replanting, when we are going to replant a plant, cleaning it is very common to stop to analyze its roots and with these observations we can find the following situations: roots distributed throughout the entire volume of the substrate; roots distributed in the outer contour of the substrate clod; roots of living outside and roots of dead inside.This distribution of roots is related both to the aging of the substrate and to the type of substrate used. Substrates based on fibers and tending to compaction in general most of the roots are concentrated in the external contour of the substrate, because this portion is more ventilated, allowing better development of the roots, while the center of the clod is compacted, very muffled and very humid, being a bad environment for the roots, which make the majority grow outside and the few inside that one day had grown die. Substrate of pine bark and coconut chip, when very old will also present this type of distribution of roots along the clod for the same reasons. Already inert substrates or barks of long durability, that do not compact usually present a distribution of roots throughout the volume of the clod, which allows a better nutrition, fixation and tolerance of the plant to stresses, being the gravel is one of those that allow to have a very dense, and occupying the whole volume of the clod. This is due to the fact that the ventilation in these materials is well distributed throughout the entire volume of the substrate, thanks to the large number of macropores along the whole lump that do not change over time. There is still a chance we will come across, with a plant that inside the vase the roots are all dead, even in the outline of the clod, but the outside are all alive and this already happens because really the substrate already gave what had to give and it should be changed a long time ago and it was not.
Now a personal question: How important is it to understand the distribution of roots in the clod?Answer: This distribution tells us if the substrate is of good quality or not and if the container we are using is also suitable, allowing good ventilation of the same, remembering that the correct choice of container is also of paramount importance.
The last tip is that substrate assembly can vary according to your region’s climate and environment conditions, crop preferences and other factors other than the crop itself. Certain mixes or materials may be better or worse, depending on the region, and in order for us to be more correct, the good old orchid phylum is still valid, that is, the constant practice of observation.
Staff regarding substrate was what had to happen to you. I hope it is of great help and that it helps a lot in the cultivation of all. Now we will see in the second part of this article, which will deal with the problems of finding quality substrates and alternatives to get around the problem.