How to choose the soil for cacti?

Ariocarpus hintonii in flowerpot

Image - Flickr / douneika

Do you know how to choose the soil for cacti? These plants are very sensitive to waterlogging, so much so that it is often enough that we over water once or twice for their roots to suffer irreversible damage. And, of course, in many nurseries they are always for sale with peat, a substrate that maintains humidity for a long time, which is not the most suitable for these succulents.

So if you have doubts, don't worry. Then We are going to talk about the different types of cactus soil that there are, and which one you should choose or what mixture you should do so that your plants are well cared for.

Where do cacti live?

Cacti live in desert areas

The vast majority of cacti are plants native to the desert areas of America, both North, Central and South, although it is true that many species are concentrated in southern North America, with Mexico being one of the most fortunate countries in this area. sense, with about 518 endemic (of the 1400 accepted that there are in total).

When we search the Internet for photos of cacti in their respective habitats, We quickly realize that practically all of them usually coincide:

  • Sandy terrain, with little vegetation
  • Hot and dry climate
  • Cacti grow exposed to the sun

Starting from this, we can get an idea of ​​which is the most suitable substrate or substrates for these plant beings.

What are the characteristics of a good substrate for cacti?

Potted Cactus

So that there are no problems, or at least none related to the substrate, the ideal is that it meets these characteristics:

Sandy

But beware, not beach sand, as it has a high concentration of salts that would burn the roots of the cactus. No. When we talk about sand and cacti, we refer to volcanic sand, formed after the cooling of the melted mass that comes out during the eruption of volcanoes.

There are many types, as we will now see, but all of them are sold in more or less small pieces or granules, which are very, very hard.

Excellent drainage

akadama

Being sandy, drains the water very fast. Depending on the type of sand, it can be kept moist for an interesting time so that the roots absorb the water they need before the substrate is dry again.

How do you know if it has good drainage? Just watering 🙂. In the case of cacti, it is recommended that, as soon as we start watering, the water begins to come out through the holes in the pot.

Should it be rich in organic matter?

Cheek

Plants, in general, have roots whose function is clear: to absorb the water and the nutrients dissolved in it, as much as they need. But when we talk about cacti, things change. The reason is the following: in the places where they grow naturally, there is hardly any life (animal and plant) that always remains in the same place.

And of course, as there is hardly any life, there is hardly any decomposing organic matter. So where do they get the 'food' that cacti require? From monsoon rains, called seasonal rains. They are torrential rains, loaded with minerals dissolved in them, and that are deposited on the desert floor, being available for the cacti. The rest of the year, they live with what they get from photosynthesis (the process by which sunlight and carbon dioxide are transformed into carbohydrates and sugars).

Therefore, cactus soil must be poor in nutrients, since with the regular fertilizer in the growing season that we give you, you will have more than enough.

Types of soil for cacti

Note: if you like other plants, such as bonsai, you will see that many substrates commonly used for these are also a good option for cacti.

akadama

The akadama It is a clay found in Japan, which has a granular shape and a light brown color.except when it gets wet it turns dark brown. It retains a lot of moisture, so it turns out to be perfect for cacti that live in very, very dry areas and we want to save some water.

The only drawback is that, being a clay, as the years go by it gets dusty, so in each transplant it is advisable to run the substrate through water, wash it, and leave it without that grit.

Depending on the size of the grain, there are several types:

  • Standard Extra Quality: grain between 1 and 6mm thick.
  • shohin: between 1 and 4mm thick. It is best suited for cacti.
  • Coarse-grained: between 4 and 11mm thick.

Do you want it? Buy it here.

Perlite

Pearlite It is a very light and porous crystal of volcanic origin, and with the particularity that it expands at high temperatures. It is white in color, so it reflects the sunlight back into space.

In gardening it has many uses, but for cacti it is great mixed with conventional peat-based substrates, since improves water drainage.

You can buy it from here.

Cheek

It is a volcanic igneous rock, formed when magma cools from being a liquid to a solid. The density is very low and very porous, and its color is gray or white. 

Unlike akadama, when watering hardly changes color, and retains little moisture; in fact, it dries fast.

Also, depending on the size of the grain, there are several types:

  • Medium grain: between 3 and 6mm thick. It is the most suitable for cacti.
  • Large grain: from 6 to 14mm.

You want it? You can buy it from here.

Universal substrate

The universal substrate for plants it is a standard mixture of peat, perlite, some compost and sometimes they also add coconut fiber, to grow a wide variety of plants. They have the peculiarity that they retain water well, and depending on the amount of perlite they carry, they are also good for cacti.

There are many brands, Flower, Fertiberia, Compo, Battle, etc. In my experience, the most recommended for our favorite plants are the Flower and the Fertiberia, because even if they dry completely they do not become "blocks" of earth difficult to re-moisten like others. However, adding 10-20% more perlite never hurts.

You can buy it here.

How to make homemade cactus soil?

If you want to make a more or less homemade one, you just have to mix, in equal parts, peat, garden soil and sand (it can be river). Thus, they will grow well.

We hope that now you know how to choose the substrate for cacti.


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