Cacti make excellent houseplants, and under the right conditions, they can be grown indoors year-round. However, compared to other types of plants, cacti have unique needs when it comes to soil and regular potting mix or potting soil is often not sufficient. Luckily, specialty “cactus soil” is readily available at most nurseries and garden centers, and you can even create your own if necessary.
You may be wondering what cactus soil is and how it differs from a regular potting mix. You might even be considering whether cactus soil is really necessary to grow happy, healthy cacti indoors.
Here’s the lowdown on why cactus soil rocks (pun intended!) and why you should be using it for all of your cacti.
What is Cactus Soil?
Cactus soil, or cactus mix as it is sometimes referred to, is a blend of mainly inorganic materials such as sand, gravel, pumice, and/or perlite that is ideal for planting cacti and succulents thanks to its superior drainage.
Why is Cactus Soil Beneficial?
Cactus soil is beneficial for growing cacti because it mimics the native environment in which these desert plants are accustomed to growing. Cacti have shallow, delicate root systems that will not thrive in potting mediums that are overly dense. They are also drought-tolerant and easily susceptible to root rot, meaning they won’t grow well in soil that is high in organic matter and holds excess moisture. Cactus soil mixes address all of these unique needs and are formulated specifically to help cacti do well when grown indoors.
Simply put, regular potting soil is just not cut out to provide these desert dwellers with the conditions they need to thrive.
Differences Between Cactus Soil & Regular Potting Mix
There are several key differences between cactus soil and regular potting soil or potting mix.
Regular potting mixes are high in organic matter such as peat moss, compost, and coco coir because these mediums are ideal for most foliage plants. However, cacti don’t require the same levels of organic matter as most other plants do, so cactus soil is composed of mainly inorganic materials such as perlite, pumice, grit, gravel, and/or sand.
One of the biggest differentiators between cactus soil and regular potting mix is its moisture retention. Although regular potting mix usually drains well, the organic materials in the soil soak up and retain moisture. Cactus soil does not retain moisture for as long since it is primarily made up of inorganic materials, which also helps to prevent root rot.
Cacti have delicate roots that grow best when there is proper air circulation in the potting medium. Cacti soil is less dense than a regular potting mix, which improves the aeration and allows the cacti roots to thrive.
In the desert, cacti experience long periods of drought accompanied by short bursts of moisture. To mimic this environment, cacti need a potting medium that drains well and dries quickly. Cactus soil drains quickly but retains enough moisture to allow the roots of the cacti to absorb what they need first. Regular potting mixes are not designed to drain as quickly.
Regular potting soil is rich and is often amended with additional fertilizers to help boost plant growth. Cacti are not accustomed to rich soils and do best in nutrient-poor mediums such as cacti soils/mixes.
How to Make Your Own Cactus Soil
Purchasing a pre-made cactus soil ensures that it contains everything the cactus will need without much work on your part. However, making your own cactus soil mix is also an option and it is pretty easy to do!
You will want to use a mix of inorganic materials such as perlite, pumice, sand, or gravel as well as a small amount of organic material such as peat moss or coco coir. A 2:1 mix of inorganic to organic materials should be sufficient.
In a pinch, you can also create your own cactus soil using a regular potting mix. Mix together 3 parts potting soil, 2 parts coarse sand or gravel, and 2 parts perlite or pumice. If possible, avoid using any potting mix that is amended with too many additional fertilizers as it can burn the cacti roots and cause leggy growth.