Hated, mistreated, seen with contempt, often carefully avoided. Expanded clay and peat are two highly contested and criticized elements among growers of succulent plants and cacti in particular. Net of the chatter from the Internet, are these really two materials that should be forgotten with the cultivation of this type of plant? The question remains open and every grower has his reasons, but there is a fact: on the Net, as far as expanded clay and peat are concerned, everything is said. Above all, it is said that they retain humidity excessively and for this reason they should be banned from the cultivation of cacti and succulents in general. It is said that they favor the onset of rot, that they do not let the roots breathe and much more. Why then do many serious nurserymen (and expert growers with them) still make extensive use of those elements? Simply because, as in many factors of cultivation, the point is not so much the material itself, but the type of use that is made of it.

In this article, let’s try to understand if expanded clay and peat are really such “dangerous” materials for cacti and succulents, if and how they can be used and what their real pros and cons are. (…)

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L'articolo Expanded clay and peat: are they really two materials to avoid when growing succulents? proviene da Il fiore tra le spine.

For any plant enthusiast, whether succulent or not, planting is an extremely important point of arrival. An arrival point which, in many cases, soon turns into a starting point which accompanies the enthusiast for most of his life. It is undeniable that there is no comparison between a purchased plant and one we have seen born, grow and develop from a tiny seed, even more if we have collected that seed from one of our plants. This is somewhat the “magic” of sowing: closing a circle born of a flower with another flower, the one produced by the plant originating from that first seed that we have been able to germinate, become a plant and lead to full maturity. And all this without going into detail about the satisfactions that are obtained by trying to select particularly interesting species, from flowers of unique colors to peculiar or almost unique thorns or stem shapes. As regards the procedure for sowing cacti and succulents, many novice growers “get lost” in the proverbial glass of water right after the phase least subject to our control, i.e. germination: we cannot in fact force a seed to germinate, although there are good practices that favor the birth of plants.

For many, however, the critical issues begin after that moment, that is to say in the first months of life of the plants, which are indeed delicate months because the seedlings are still weak and easily subject to rotting or parasitic attacks. It is above all to these growers that the following article is addressed, with a little “trick”, to be understood as advice, on how… to make life easier for seedlings and how to let them pass the first winter unharmed. (…)

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L'articolo Sowing cacti: how to prepare plants for the first winter and the “trick” to help them in the first few months proviene da Il fiore tra le spine.

I’m not particularly fond of crested succulents, but at the same time I’m not entirely indifferent to their charm and every so often some “monstrous” specimen ends up in my greenhouse. Small digression: if you don’t know what a “crested” or “monstrous” plant is, there is an article on the italian version of the website (you can find it here and use the internal translator). Having said that, in the last few weeks I bought a crested Cereus peruvianus monstruosus from a nursery specialized in succulent plants. The plant is in excellent health and well formed, but the substrate, as almost always happens when buying cacti, is excessively peaty, at least for the type of cultivation I’ve been using for years now. I then took the opportunity to describe the repotting operation of this Cereus, so as to be able to speak of “monstrous” plants, of repotting, of simple substrates and within everyone’s reach from the point of view of realization and of good practices to follow when buying new plants.

Here then is the report – accompanied by photos of the individual steps – of this repotting, with some useful considerations, precisely, regarding soils, new purchases and crested cacti. (…)

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L'articolo A repotting… monstrous! How to choose a cactus well and what to do immediately after the purchase proviene da Il fiore tra le spine.

In this article we see how to make a proper substrate for use with any genre of cactus and, with appropriate adjustments, with succulents, in general. We will make it, and this is the point of this article, with materials that anyone can now easily find in any place (…).

Introduction

One characteristic that any substrate for cacti and succulent plants, in general, must have is the ability to drain water and dry quickly. It is the starting point, the end to which we must strive if we want to make good potting soil for succulent botanical families. The materials we can use are virtually limitless and can also vary according to the type of cultivation we want to pursue. Spartan cultivation to obtain plants similar to those in the wild, “push” cultivation to have plants that are swollen and “immaculate-looking,” “maintenance” cultivation, that is, with no particular purpose other than to grow the plant properly, etc. The combinations we can make with various materials are virtually endless and, theoretically, we could try to prepare a suitable substrate for each individual species that we intend to grow. Each plant has its own specific needs, and even among cacti, there are the species that want more organic material, others that want exclusively mineral potting soils, others that require lime substrates, and so on.

Of course, this fact opens the door to experimentation, which I recommend to anyone who has the time, desire and curiosity to test various substrates to figure out which is the best formula for this or that kind of plant (obviously in combination with the other growth factors, such as water, exposure, temperatures…).

Here you will find an article related to one of the experiments I have done over the years.

The “common” materials

After this long introduction, going back to the purpose of this article, which is nothing more than to provide basic directions for making proper soil for cacti and succulent plants using only materials readily available in any nursery and building materials retailer. Yes, because while it is true that online we can buy (up to certain quantities, of course), peat, quartzite, gravel, sand, gypsum, pumice, and lapilli of all colours and sizes, as well as potting soils specially made for cacti or succulent plants, it is equally true that good compromises can be made with “common” materials, especially if you don’t want to have too many problems.

Field soil and marl deserve a separate discussion. Field soil means clay, which can be more or less calcareous, more or less sandy, and more or less rich in nutrients. In short, there are endless types, and the best way to know whether or not that field soil, mixed with aggregates such as gravel, pumice, and sand, is suitable for cacti is to experiment with it for at least a couple of years. We can say the same thing for marl, a material exceptional for growing different kinds of cacti (if you are unfamiliar with marl, find a specific article here). Marl is almost impossible to find commercially, and even when you get it, you should be careful because there are various types, and not all of them are good for cacti.

Learn more about using field soil and marl in cactus substrates in this specific article.

The classic mix

A first viable option for those who want to avoid problems, as I have written on several occasions, is the traditional mix of equal parts lapilli, pumice and peat. It is the most popular potting soil for growing cacti and succulents, especially in skilled nurseries. In principle, it gives good results with all cacti, even working very well for leafy succulents (e.g., Crassula, Echeveria, etc.) simply by adding a little peat or earthworm humus, to make the substrate a little richer organically. Pumice and lapilli usually come in sizes between 3 and 7 millimetres, and this type of substrate is easily found online or at skilled nurseries. Unfortunately, it is not yet found commercially in all nurseries or gardens that do not specialise in succulents.

This is the article’s main focus because this substrate can be made without difficulty by retrieving materials from any large nursery or garden store.

First of all, the peat. It is the organic component of the substrate that contains the nutrients needed by plants. Most cacti, in nature, live in organically poor soils, which is why in the correct substrates intended for these plants peat should never be prevalent. Again, peat retains moisture for a long time, while the basis of a valid substrate for succulents, as we have seen, is the ability to drain water and dry quickly. For these reasons potting soils intended for cacti, it’s a good idea not to use peat percentages of more than 40 per cent. With some species, particularly those with “taproots” (e.g., Ariocarpus), the amount of peat will have to be decidedly small: a maximum of 20 per cent of the total. On the contrary, in leafy succulents is correct to provide at least 50 per cent peat because these plants need more organically “rich” potting soils. At the same time require greater amounts of water than cacti (their substrate will therefore have to remain moist a little longer to allow the roots to absorb the necessary water).

Peat can be found in any nursery: in fact, it is the material that makes up all so-called ‘universal potting soils’, i.e. intended for any genre of plants. At the same time, peat is the basis of all other packaged potting soils that we find in gardens: from those for citrus trees to those for ornamental plants, turf, acidophilic plants, and aromatic plants. All these potting soils are composed mainly of peat (there can be different types, but it is always peat) and, as appropriate, small percentages of sand, perlite, or pumice. The only potting soil not to be considered with succulents is orchid-specific potting soil, which contains no peat (or very little of it) and is composed mainly of bark.

The same ready-made potting soils for cacti and succulents are nothing more than peat with a little sand, pumice or perlite. On their own, they are no good, but they can be considered on par with peat or universal potting soil, with the advantage that they will already contain some sand, perlite or pumice.
For the rest, one ready-made potting soil is as good as another: what matters is that it is of good quality and that the peat is fine and not rich in filaments, bark, timbers, and other things. If we want to be precise and have a choice, we use blond sphagnum peat, which is slightly acidic and is fine for most succulents.

As an alternative to peat, since from a sustainability point of view, its consumption on a global level has become excessive in recent years, one can use earthworm humus, which can be found in all nurseries.

The other two elements of the traditional mix are pumice and lapilli. You can find both in well-stocked gardens, with one “flaw”: the size is almost always coarse, around 10 millimetres. There are no problems if you have to re-pot large succulents. But if you have seedlings to be placed in 5 or 7-centimetre pots, there are two alternatives and you have to be patient: you can either sift the material keeping the smaller part, or you can use the hammer (with a greater dose of patience) and break pumice and lapilli into smaller pieces. Of the two materials, in my experience, pumice is best, simply because it dries faster. With these three elements (universal potting soil, pumice, lapilli), we can already make a perfect substrate that is very popular in growing cacti and succulents. Mix well one part peat (as a unit of measurement, you can use the scoop) with one part pumice and one part lapilli, and the substrate is ready. If it is intended for leafy succulents, add a couple of scoops of peat to the final mix; if you intend to use it for “mangy,” very moisture-sensitive cacti, reduce the amount of peat by half.

The ‘simple’ mix

A valid alternative to the classic pumice/lapillus/peat mix, which can also be found for sale online or in large bags at some nurseries specialising in succulents, is the potting soil that I have prepared in the video published below. It is an even simpler but perfect substrate for almost all cacti and succulents, which I use when I finished my specific mixtures. Again, the starting point is peat. If the universal potting soil is of good quality, there will be no need to sieve it because it will not have any residual bark, coconut fibre, wood and other ‘impurities’. Good quality universal potting soil, it bears repeating, is usually peat of two or three types already sieved fine (and even this is fine because we will be adding the ‘coarse’ part to the compost), and added with a little pumice or, more often, perlite.

To one part peat, we add one part pumice and half a part fine sand, and the substrate is ready. As I have written before, the pumice we find in gardens is usually coarse-grained but can be sieved or crushed if necessary. Sand, on the other hand, is easily found at building material dealers. Caution: it must be river sand, preferably silica sand. Avoid sea sand. As I pointed out, in this substrate to one part peat and one part pumice I add only half a part sand because fine sand is only very useful in small quantities. If we were to make potting soil with only fine material (sand, pure peat or pumice powder, for example), we would create a potential succulent ‘killer’. In fact, after a few waterings, the substrate would compact and remain constantly moist, causing asphyxiation and root rot. Therefore, it is essential to have both a fine part (useful for rooting) and a coarse part in the substrate, which can make the soil ‘loose’ and increase its drainage capacity.

As I explain in the video, we can make small changes to this mixture if necessary so that it is also perfect in specific cases. For example, if we have to re-pot leafy succulents or hardy plants such as Echinopsis or epiphytic cacti such as Epiphyllum or Schlumbergera we can increase the amount of peat a little (add a couple of shovelfuls at the end and mix everything well). On the contrary, if we are dealing with delicate, slow-growing and particularly sensitive to stagnation plants such as Ariocarpus, Pelecyphora, Aztekium, Copiapoa and others, we can halve the amount of peat and add gravel or quartzite to the substrate.

The latter are also readily available materials in any city. Gravel (with a grain size of between 3 and 5 millimetres) can be found at building material dealers, often mixed with sand. In these cases, with a bit of patience and a fine-mesh sieve, you will be able to separate the sand from the gravel and thus be able to use them in separate dosages. On the other hand, quartzite can be found in aquarium shops or pet shops. There are countless types of quartzite: it can be bought in various sizes and colours. Just be sure it is not “treated” or in any way coloured material.

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How much light do cactus need? A summary table
How to repot cacti and succulent plants
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L'articolo A good cactus potting soil with materials readily available in any nursery? Here is how to do it proviene da Il fiore tra le spine.

Let’s see in this article how to correctly choose the plants for our compositions (…)

Avoiding difficult cohabitation

First of all, compositions with different plant families should be avoided: succulents together with tropical plants such as orchids, or succulents together with carnivorous plants, just to mention a couple of examples, are combinations to be discarded without any doubt. The needs of plants belonging to different families can be completely irreconcilable, and by making an arrangement we are forcing some plants into a coexistence (in a pot, bowl or any container) that in nature would never occur and that in the long run is bound to fail. So why should we throw away time, labor, materials and plants just to enjoy for a few days or a few weeks a combination that only works from the point of view of our aesthetic standards?

Being coherent with the philosophy of this site, let’s then talk about arrangements made only with succulent plants (vulgarly known as “fat plants”). Again, however, it’s important to consider that the world of succulents is very broad and includes dozens of families, hundreds of genera and thousands of species, each with its own specific needs. In some cases the needs are compatible, in others less so, and in others not at all. A first important distinction to do is between cactaceae and noncactaceous succulents. As is usually said, while it’s true that all cacti are succulent plants, it’s true at the same time that not all succulent plants are cacti. And the difference between a cactus and any other succulent (e.g., a Lithops, a Crassula, an Euphorbia, etc.) can be quite remarkable not so much in shape and appearance as in growing requirements. So much so that the coexistence of these plants in a single pot may prove impossible or at any rate short-lived.

For those who want to approach the subject and begin to understand the difference between a cactacea and any other succulent plant, I recommend reading this introductory article of mine on classification. Don’t be frightened by the topic: actually learning to distinguish the various succulent plant families is less difficult than it may seem!

Choosing plants

The first criterion in identifying plants for composition is based, of course, on the personal taste. Anyway, it may be useful to keep in mind a few simple pointers. For example, it may be interesting, for the purposes of the final result, to choose plants with different bearing, so as to achieve a “wavy” composition, with tree-like succulents and others with low or prostrate habit. But even this, all things considered, is related to the aesthetic taste, and compositions made with several specimens of a single succulent genus can also prove pleasing. One example? The classic bowls filled with Lithops, the so-called “stone plants”: they are beautiful because of their similar shape but infinite color shades. On the other hand, the “objective” factors to regard when placing several plants in one container are the following: soil, frequency of watering, minimum tolerated temperatures, and exposure. Assuming that we are talking here about succulent plants, the combinations can be many, as long as we choose plants that have similar needs in terms of soil, watering, temperature and exposure. It is enough to know a minimum of the characteristics of the various succulent families to select which plants we can combine and which are better not to keep in one container. An example: I do not recommend putting cacti with leafy succulents (e.g., Crassula, Echeveria, Hoya, etc.) in the same composition. The reason is very simple: cacti can live for months without water, while most leafy succulents if they stay dry for a few weeks start to perish. The water requirements of these families are very different, and while coexistence is still possible, my opinion is that it’s not the case to complicate life and, above all, make the plants suffer or otherwise grow in unsuitable conditions.

Related to the frequency of watering is the issue regarding the potting soil: a cactacea, as well as a Lithops or several species of Euphorbia with a compact bearing, grows best in poor substrates, with a lot of aggregates and little organic material, while leafy succulents need significantly higher percentages of organic matter (at least 50 percent). It’s clear that in a container shared by all plants, we are not able to use different potting soils according to individual needs, but we have to to stick to the criterion of “one size fits all,” that is, the product that will satisfy all needs.

Temperatures are also important, unless we decide to keep the composition indoors all year round (but I’ll never recommend it for succulent plants). There are succulents, such as cacti, that in dry potting soil can tolerate temperatures well below freezing without problems; others that cannot go below 12-14 degrees (e.g., Adenium, several species of Euphorbia, and all succulents native to Madagascar).

Similar discussion for exposure: some succulents want a lot of light, if not direct sun, while others do not tolerate excessive levels of sunlight and grow well in half shade (many Euphorbia and the Haworthia, to name a couple of cases). Clearly, if we put several plants in one container, it’s appropriate to choose specimens with similar light requirements, so that we do not have problems or imbalances in growth, with healthy plants and others sunburned or etiolated and suffering from too much or too little sun.

Choosing the container

This is a purely aesthetic question related to personal taste, as much for colour as for shape (square pot or rectangular box, round pot, tall pot, low pot, bowl, etc.). Just a couple of considerations: the container chosen for compositions must be adequate for the number of plants we intend to place and must be deep enough. In other words, the container must be able to comfortably accommodate the root bread of the plants that you place there. This may seem like an obvious clarification, but taking into account that very often for compositions we use those beautiful enameled pots for bonsai, I think it’s necessary to remember that the less space we give the roots to be able to develop, the more we limit the growth of the plants (and maybe this is exactly what we want: to make a composition in which the plants are always “under control,” that is, of limited size…). When choosing a container, the only imperative is: make sure it has drainage hole(s)! Water stagnation is detrimental to all types of plants, except aquatic plants…. Regarding the material, anything can be ok, and each element, terracotta, plastic, aluminum, wood, can be valid or not.

For a more in-depth look at the topic, I recommend reading this specific article.

How to proceed

Once the plants and container have been chosen, the first thing to do is to try arranging the succulents in the new pot or bowl without removing them from the plastic pots to get an idea of how to make the composition. For this purpose, it may be useful to spread a layer of one or two centimeters of expanded clay on the bottom of the new pot: this way we can easily move the plants around and try several combinations to get arrangement we like best. Of course, we can also decide to include other elements in the composition, such as rocks or pebbles of various sizes. Again, the “trial run” with the plants still in their individual pots is most useful to get clear ideas before proceeding definitively.

Once we have found the arrangement we prefer, it can be useful to take a photo with the cell phone (which is always handy), so that any doubts can be cleared up immediately when we go to repot the plants by removing them from their individual pots to arrange them in the new container. If the plants are in the correct substrate, i.e., peat and aggregates, it’s enough to take them out of the pot, check that there are no pests in the root ball, and place them in the new container, at the bottom of which we have placed some potting soil. If, on the other hand, the plants we need to repot are in pure peat (as is often the case when buying them from non-specialized nurseries), it’s a good idea to remove some of the potting soil and untangle the roots as much as possible. With cacti this procedure should be done very firmly, removing all the peat with the help of a brush and, in case the soil loaf is very dry, with a stream of water (before repotting, however, it’s necessary to leave the plant with the roots in the air for at least a week).

Once the plants have been placed in the new container, all we have to do is fill it with potting soil, starting from the edges and going all the way to the center, avoiding leaving gaps here and there. This is both to give stability to the plants and to avoid stagnation or “puddles” when we water. When we have filled the pot with the substrate and stabilized the plants, it will be useful to tap the container lightly and several times on the shelf so that the potting soil is evenly distributed. Remember to stand at least an inch and a half below the rim of the pot with the substrate so that there is no spillage of potting soil when we water.

Finally, to complete the composition, if you like the effect, it may be useful to spread a layer of grit on the surface. You can use river gravel or aquarium quartzite (you can find it in every color): this is also a matter of personal taste. Beyond the aesthetic aspect, however, spreading a relatively heavy layer of inert material on the surface is a great way to even out the color of the substrate and to keep the pot tidy, especially when watering. The layer of inert material (it is best to avoid porous materials such as pumice and lightweight materials such as perlite) should be one centimeter thick at most. If we use gravel or quartzite, the water from watering flows quickly between the pebbles and doesn’t form stagnation around the collar. At the same time, the grit layer ensures that in the warmer months the water doesn’t evaporate too quickly, particularly if we have used a very draining potting soil. Another material to avoid for the surface layer of the arrangements is fine sand: it retains moisture around the collar of the plants for a long time, and with “vigorous” watering it leaks everywhere.

Landscaping

Quite different from the concept of “composition” is that of “landscaping“. In this second case, compositions are made with plants, but the ultimate goal is to reproduce as closely as possible the aesthetic appearance of the natural habitat. Take a look at this video and you’ll understand immediately what I mean! Thus, for these compositions there are very precise rules that govern the choice of plants, potting soil, elements that embellish the composition (rocks, branches, shrubs). In short, here the aesthetic criterion is oriented by reality, so much so that in order to create these small “habitat cutaways” one is inspired by Nature, observing in detail photographs of the environment one intends to reproduce and using materials that are compatible if not identical to those found where succulent plants grow wild (marl, chalk, field soil, sand, etc.).

If you want to know everything about the materials with which to make substrates, here you will find a specific article.

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Correlated articles

Six identical cacti in three different soils
How to repot cacti and succulent plants
Substrates for cacti and succulents
Fertilization: how and when

© The texts, videos, photos and graphic elaborations of the site “Il fiore tra le spine” are original material and are covered by copyright. It’s forbidden to reproduce them in any way.

L'articolo Compositions with succulents: how to choose plants and what is important to know proviene da Il fiore tra le spine.

Do I use lapillus or just pumice? Is peat really a cactus-killing devil, as we hear people say? But then why nurserymen cultivate their plants nearly 100% with peat, and their plants don’t die in the greenhouse? The question about materials and elements that end up in compost for cacti and succulents is a limitless one. Firstly because the variables are endless and range from growing regimes, environmental factors, latitude, to plant type (for example, there are differences in substrate requirements between a caudiciform and a cactus). Then, because the same elements, as like the field soil, can vary immensely between them – for example, based on the area where it is picked up: it’s evident that the loam of the Po Valley, where I live, cannot have the same chemical characteristics as that one existing in Bolivia, for example. So, how can we orient among the many elements and materials we can find – some easily, others less – to mix them and make good compost? A first answer, perhaps obvious but reasonable, is to do experience and direct observation. In a word: experimentation. Another one, trivial but overlooked, is knowledge – the knowledge of the single “ingredients” properties that create the substrate and of the individual plant’s needs.

Let’s explore the topic in the following article. (…)

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L'articolo How to make the perfect substrate for cacti and succulents. Is peat really a cactus killer? proviene da Il fiore tra le spine.