Once you’ve figured out how to water your succulents correctly, the second most important thing is getting them the right soil. In fact, without proper soil, it won’t matter if you’re watering the right way or not!
A good soil accomplishes 3 things for a plant:
- It provides nutrients, mostly in the form of nitrogen and phosphorous (N and P).
- It provides anchorage. The roots need soil with substance to be able to dig in and get a grip for stability.
- It absorbs and makes moisture available to the plant. Different soil types hold water for different lengths of time.
What Makes a Good Soil for Succulents?
When we’re selecting a soil for succulents, our primary focus is making sure it has good drainage. That means we’re focused on the ‘moisture’ part of that list above.
First of all – what is soil drainage? Simply put, it’s how fast water leaves the soil. After you water a plant, some of that water should come out of the bottom of the pot, but most of it will stay in the soil. That water either has to be taken up by the plant or evaporated into the air.
As it turns out, succulents and cacti require different soil than regular houseplants. Here’s 16 different succulents in case you’re interested. Most houseplants are tropical plants. They’re originally from a place that probably has lots of rain and ambient humidity. Their soil is also naturally rich in nutrients because of all of the other decomposing plants.
Succulents, on the other hand, come from deserts or other arid (dry) regions that generally have little rain and poor soil quality. The dirt there is probably coarse and gritty and lacks nutrients.
Obviously, it’s usually best to recreate their natural conditions as closely as possible. You might be surprised, however, that the most important thing to copy isn’t the amount of nutrients they get – it’s the amount of water.
Soil composition is important
In essence, soil is made up of two things – organic matter and inorganic matter. (Actually, you could argue that everything in the universe is made up of those two things).
Organic matter in this context means stuff that was once alive but is now dead. It can be in various stages of decomposition, or just regular dead. Some examples are:
- Peat or sphagnum moss
- Decomposing plants or animals
- Coconut coir
- Leaf or bark shreds
Inorganic matter, then, is everything that was never alive. In the case of dirt, it really just means minerals. Dirt is mostly made out of varying ratios of clay, silt, and sand.
Add organic and inorganic matter together and you’ve got soil.
Now back to water. The more organic matter that’s in the soil, the more water it holds. See what I’m getting at here? More organic matter means less drainage (and wetter soil). It follows that succulents prefer soil that has very little organic matter.
How do you know if the drainage is adequate?
So, we know what soil drainage is and we know how to get it. But how much drainage is enough?
As a rule of thumb, your succulent’s soil should be dry within 1 to 1.5 days of watering. And I mean dry. Bone dry.
There’s a quick way to test how dry the soil is. Stick your finger in the pot an inch or two into the soil. It should feel not only dry, but also warm. If it feels “cool” at all, it’s probably actually slightly damp and you’re misinterpreting the sensation. Need help in repotting your succulents for the perfect drainage system, click here.
Most soil is bad soil
We’ve been talking about how bad wet soil is for succulents, but we haven’t even mentioned why that is. Well, here’s the answer.
Wet soil can cause root rot. Read all the popular ways a succulent can die so that you can prevent this from happening.
This is a risk for all plants, but it’s especially dangerous for succulents. They aren’t accustomed to being wet for extended periods of time. In their natural habitat, water is wicked away by the dry soil and hot air very quickly.
Root rot is a particularly interesting disease. It may surprise you to learn that plants breathe mostly through their roots – not their leaves. They take in both carbon dioxide and oxygen (yes, they need oxygen too) that is present in the soil.
That’s why people are always talking about loose, aerated soil and how great it is. It’s also why worms are great for gardens – they break up the soil and create tunnels for air to reach the roots.
When soil is wet, however, air can’t move through it (duh). The plant has to “hold its breath” until the soil dries out again and it can breathe. If it takes too long, the root will drown and begin to rot.
Apparently, succulents just succ at holding their breath.
Choosing the Right Soil for Succulents
That may sound dire, but it’s really not that hard to choose a good soil for succulents. Just minimize the amount of organic matter and use those good watering practices we discussed.
Every succulent species has its own particular needs and wants, but 99% of them are cool with pretty much the same dirt. Just to be sure, watch how a plant reacts after being put in new soil and adjust your care accordingly.
How to make your own succulent soil
You can make your own succulent soil pretty easily; you probably already have everything you need at home. Here’s our recipe:
- 2 parts potting soil. You can use any old dirt you have around. I like to use the Miracle Gro Succulent and Cacti mix. By itself, it’s not the best succulent mix (since it inexplicably contains a lot of organic matter like peat moss), but it does make a great base for mixing your own soil. Try to stay away from using dirt that is made of compost.
- 1 part perlite. This is the not-so-secret ingredient of great succulent soil mixes. Perlite is actually a type of volcanic glass that is “puffed” using extreme heat, just like Rice Krispies (seriously). Perlite is useful because it is a large particle with air pockets in it so it keeps the soil loose, promotes soil drainage, and helps with airflow.
- 1 part grit. “Grit” is just any large inorganic particle, ideally of varying sizes. Grit does much the same thing that perlite does (and perlite is a kind of grit). Examples include: large sand particles such as construction sand, small gravel or rocks, or chicken grit.
That’s what we use to get all these nice plants you see here on Succulent City, but feel free to experiment.
Best commercial succulent soils
If you don’t feel like getting your hands dirty and mixing your own soil, there are a couple really great succulent and cacti mixes that are commercially available.
Black Gold Cactus Mix by Sun Gro Horticulture is the gold standard of succulent soils. It’s pretty incredible how well-balanced it is – there’s just enough organic material to fertilize the plant and plenty of inorganic stuff to balance it out and have excellent drainage. You can’t go wrong using this mix.
Bonsai Jack Succulent and Cactus Gritty Mixis another fan favorite, but a little different. It’s a “gritty mix” which means it has virtually no organic matter and retains zero water. It’s technically not even soil. It’s awesome for succulents, especially the picky ones, but you need to adapt your watering a little to accommodate a mix that holds literally no water. Recommended for moderate to advanced growers.
That’s just about everything you need to know about soil and how it relates to succulents and cacti! Do you need any clarification or have any questions? Do you have a soil recipe you want to share? Let us know in the comments below!