Succulents are special plants that add an interesting texture to your garden, conservatory or plant collection, but it’s important to give them the appropriate soil to grow in so that they thrive. I am going to tell you about the type of growing medium you should be using when planting your succulents, and break it down, step-by-step so you understand why. I will also tell you my favourite soil recipe for the perfect succulent potting mix.
This guide is relevant to succulent planting whether you are buying your soil from a garden centre or making your own mixture.
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What makes a succulent a succulent?
There are many different types of succulent plants including Echeverias, Sempervivums, Agaves, Sedums and Aeoniums. The characteristic that links these different genera is their ability to store water and withstand drought. They are low-maintenance plants that require infrequent watering – an attribute that makes them incredibly popular amongst houseplant collectors and plant lovers.
Where are succulents from and what is the soil like?
We can take guidance from where succulent plants originate to understand the best type of soil for potting them in. Succulents are mainly native to arid, dry regions (including deserts) where rainfall is minimal and the soil quality is poor. This gives us a clue to the type of soil we should be using when planting our succulents. The soil in these places is generally lacking in nutrients, very free-draining and porous – which is what succulents like. The free-draining element stops the soil from becoming water-logged and excess water is kept away from the roots in slightly porous mediums (which prevents root rot). Succulents also require an element of stability, so potting mediums should provide anchorage for the roots to grip and dig in.
What soil characteristics are important for succulents?
When selecting the best soil for succulents the most important quality to replicate should be good drainage. This is basically how fast the water leaves the soil, and in “good draining” soil, it leaves relatively quickly. Soil composition is essential in determining whether the soil is free-draining or not.
What is soil composition?
Put simply, soil is made up of two elements – organic and inorganic matter. When we are talking about potting mixtures, organic matter includes everything that was once living and is now decaying or dead (decomposing plants and animals, compost, peat, manure, fallen leaves and bark, coconut coir etc.). Inorganic matter is everything else that was never alive (clay, silt, sand etc.).
Why is soil composition important when choosing one for succulents?
The amount of organic matter that is present in a soil affects how much water it holds. The more organic matter that is in a soil, the more water it holds. As succulents require soil that holds little water, soil with less organic matter is best for them. Soils with less organic matter are less nutrient-rich, which is also what most succulents prefer.
How do I tell if my soil is free-draining?
The best way to tell if your soil is free-draining and therefore suitable for the succulents planted in it is to stick your finger into it. Succulent soil should be dry within about a day of watering, so poke your finger into the soil about one to two days after watering to check that it feels dry and not cold. If it feels cold, then it is probably wet.
Why is drainage important for succulent plants?
Succulents are at high risk of dying from root rot if they are planted in soil that is very wet because it holds too much water. This is because succulents are not used to being in waterlogged soil for long periods - again we must try to replicate the soil that is found in the areas they originate from. Plants breathe mainly through their roots and take in carbon dioxide and oxygen present in the soil (they also breathe through their leaves, but not so much gaseous exchange happens here). If soil is water-logged, there is no space for the air and aerobic respiration gives way to anaerobic respiration (without oxygen). In effect the plant has to “hold its breath” until the soil dries out and there is air present again. Plants cannot respire for too long anaerobically (particularly succulents) so if the soil takes too long to dry out, the roots drown and begin rotting.
What soil can I buy for my succulents?
You can make your own potting mix for your succulent plants, or you can buy specialist compost for cacti and succulents online or in a garden centre. A couple of commercially available cactus and succulent composts I have used with success are Westland’s “Cacti & Succulent Potting Mix” and “Cactus & Succulent Focus Repotting Mix”. Both are widely available and are designed to be free-draining with an adequate balance of nutrients and added wetting agents.
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How to make a potting mix for succulents -
It is incredibly easy to create a DIY succulent soil, and you probably already have everything you need to create one. It works out cheaper than commercially made ones and allows you to have control of the ingredients going in. You need to include components for drainage and aeration, and ensure that it is not too rich (not too much organic matter).
- 1 part coarse sand or grit - This keeps the soil “loose” to promote soil drainage and help with airflow
- 1.5 parts perlite - This is a volcanic glass that when heated puffs up resulting in a very lightweight material. It is porous, aids drainage and prevents soil compaction.
- 1.5 parts soil - Use ordinary fresh, sterile potting soil. Make sure you choose one that is not too rich or one that contains vermiculite or moisture-retaining additives.
- You can add a small amount of coconut coir to very rich soils. Proceed with caution given the water-retentive characteristics of coir - if you add too much it will become waterlogged.
- Mix - Put all the ingredients into your wheelbarrow/trug/potting tray/bucket and mix well.
- Keep - Store any leftover succulent mix in an airtight container in your shed or garage to use another time.
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Hopefully, that is everything you need to know about soil for potting succulents. If you have any questions, please ask me in the comments below. You can also send me an email at firstname.lastname@example.org.