Growing succulents with coal cinders: a handy, money-saving way to prevent soil compaction

For mixing succulent potting media, coal cinders are an excellent choice because they are easy to get hold of and cost almost nothing. After being burned at high temperatures, coal is virtually free of pathogens and insect eggs and can be used directly as a granular soil component; in addition, coal cinders contain many trace elements. They are air-permeable and drain well, and their performance is no worse than that of orchid stone or Kanuma soil; for enthusiasts who grow succulents in large quantities, mixing cinders into the soil offers a big bulk-filler advantage. Some flower growers say that sieving coal cinders is especially troublesome, leaving you covered in dust and with dust all over the house, making cleaning even more tiring. Here is a method for everyone: you can crush them in water; when coal cinders meet water, they definitely will not send dust flying.

As a medium for growing succulents, coal cinders are a fairly common material and are basically widely accepted. If there is any controversy, it is probably about whether growing in coal cinders is really that good, and to what degree. Here is a brief description of the pros and cons of growing with coal cinders, for fellow growers to choose from. The advantages of coal cinders are that they are air-permeable and drain well, and their performance is no worse than that of orchid stone, pumice, or Kanuma soil; they contain a great many trace elements, such as iron oxide, calcium oxide, magnesium oxide and so on; they contain the media needed for growing succulents, such as large amounts of burned stones and loess; they reduce the medium cost to almost zero, and especially for enthusiasts who grow in large quantities, they offer a big bulk-filler advantage; after high-temperature burning, they basically leave no pathogen residue.

The disadvantage of coal cinders is that after burning, things like sulfur are produced, making them fairly alkaline, so it is better to soak them in water before use. Sometimes some honeycomb coal briquettes have not been fully burned, resulting in a relatively large amount of black particles when sieving; with this kind of honeycomb coal, it is best to pick them out by hand and discard them. In some areas the coal cinders are strongly alkaline, so they need to be soaked in water for neutralization. If they are used directly without sieving, there is too much dust; if they are used directly in a soil mix, sometimes the roots, because of the poorly aerated medium, can cause the plant to suffer root rot or a higher probability of rotting. Sometimes after the medium has dried out completely, when you water again, you will discover a particularly fatal problem: the water simply does not soak into the medium all at once; when the water floats on the surface of the medium, the muddy sludge produced will splash everywhere. Personally, I suggest sieving out a reasonable particle size range, and after sieving, it is best to rinse with water and dry before use.

So coal cinders must be washed with water before use, because otherwise there is too much dust; if they are used directly in a soil mix, the plant roots may rot due to poor aeration. Furthermore, sometimes after the medium has dried out completely and you water again, you will discover a particularly headache-inducing problem: the water simply does not soak into the medium all at once; at this point the water floats on the surface of the medium, and the muddy sludge produced splashes everywhere. Honeycomb coal cinders still need to be sieved to select the appropriate size range before use. One portion I sieved out is coal cinders of about 1-3 mm, and another portion is coal cinders of 3-6 mm.

It is recommended to choose coal cinders that are thoroughly burned; visually, they look slightly red and rough in the middle, while those coal briquettes that are not thoroughly burned show black areas when broken open and are not suitable for use. Sometimes our soil tends to compact; mixed into the soil, coal cinders play a role in dispersing the soil, that is, making the soil less likely to stick together. This keeps the soil in a loose state at all times. In this way they can improve the soil's water permeability and aeration. Once this physical property of the soil is improved, the plant's root system will become well developed, and with a well-developed root system, succulents will naturally grow well.

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