Cacti make excellent houseplants under the right conditions, but providing them with soil that is well suited to their needs can be difficult. Fear not! Speciality cactus soil will provide what’s needed for a healthy plant and is often available at nurseries or garden centres.
You might be wondering what cactus soil is and whether it’s necessary to grow happy, healthy cacti indoors.
Fact: Cactus potting mediums differ from regular potting mixes in that they are specifically designed for plants of the Cactaceae family such as prickly pears, chollas, barrel and Christmas cacti.
You know how there are some materials that make perfect sense to use for something, but you never think about it because it’s just so obvious? That’s cactus soil!
What is Cactus Soil?
Cactus soil also called a cactus mix, is made up of sand, gravel, pumice (crushed volcanic rock), and/or vermiculite that provides the perfect drainage for growing cacti and succulents.
Why is Cactus Soil Beneficial?
Cactus soil, which comes from native desert environments, is beneficial for growing cacti because it mimics the environment in which these plants thrive. The shallow roots of cacti do not grow well when confronted with a potting medium that is overly dense. When cacti are grown indoors, they have special needs that need to be met for them to grow well. Cactus soil mixtures address these needs and can make the plants thrive in conditions typical of an indoor environment.
Simply put, regular potting soil is not supportive of the growth conditions of these desert dwellers.
Differences Between Cactus Soil and Regular Potting Mix
While the texture and composition of potting soil vary between brands, there are a few key differences between potting soil or cactus soil.
Composition
Mixed potting soil for cacti is not as rich in organics, since they require different conditions than other plants do. The regular potting mix contains peat moss, compost, and coco coir because these are good mediums for most foliage plants.
Moisture Retention
The biggest difference between cactus soil and regular potting mix is moisture retention. The regular potting mix usually drains well, but the organic materials in cactus soil soak up and retain water that can potentially prevent root rot.
Aeration
Cactus roots require proper air circulation around the medium. The soil mix for cacti is less dense, which gives them more room to grow and shelves their delicate structures.
Drainage
There are two extremes in desert climates- long periods of drought and short bursts of moisture. For cacti, a potting medium that dries quickly is preferable to unify the plant’s needs. Parts of the average potting mix may retain water while other parts dry out too slowly for cactus roots to do this process efficiently.
Nutrient Content
Regular potting soil is often amended with additional fertilizers to help boost plant growth. Cacti are not accustomed to these rich, nutrient-poor mediums and do their best in more austere conditions.
How to Make Your Own Cactus Soil
Purchasing a pre-made cactus soil ensures that it contains everything the plant needs. Properly, pre-made cactus soil contains a balance of inorganic materials (such as perlite, pumice, sand and gravel) as well as organic material, such as peat moss or coco coir.
However, homemade cactus soil is an excellent option as well. Simply mix 3 parts potting soil, 3 parts sand or gravel, and 2 parts perlite or pumice together. Don’t use a potting mix that contains fertilizers – the fertilizer can burn the roots of your cacti and cause them to grow taller than usual.