Potting Soil Versus Potting Mix: What’s the Difference?

We’ve all seen it - “potting soil” and “potting mix” being used like they’re synonymous. In reality, they’re totally different products with completely different applications!

Sure, they’re both growing media for plants, but each has its unique strengths and limitations. So before you start your next gardening project, glance through our blog to understand the difference between the two. The right potting mix or soil will not only help your plants thrive, but it’ll also save you a tonne of time, effort, and money. 

What is Potting Mix? 

First off, a potting mix isn’t soil. In fact, it doesn’t even contain dirt or soil. It’s a lightweight, sterile, specially blended assortment of materials that have been selected to give plant roots exactly what they need - nutrition, structure, air, and water. What’s amazing is the potting mix’s ability to do this without using any of the normal components found in soil. 

So, what is a potting mix made of? Popular materials include peat moss and perlite to help with drainage and aeration and vermicule to retain water and slowly release it to the roots.

Ingredients like peat moss, bark, or coconut coir are added for their fibrous structure. The addition of slow-release fertiliser (artificial or natural) makes up for the mixture’s lack of common nutrients and microbes found in garden soil. This ensures the plant gets the key elements it needs for growth, like nitrogen, potassium, and phosphorus. 

What is Potting Mix for?

If you’re planting in pots or growing a vertical garden, then potting mix is the perfect growing medium for your plants for three reasons: aeration, weight, and drainage.

Potting mixes are “fluffier” growing mediums that allow water and air to penetrate the roots properly, even in the confines of a small container. This fluffy texture boosts root aeration, which is crucial for healthy potted plants. 

And it gets better.

With potting mix, you don’t have to worry about root rot if your pot has proper drainage (like our Planter Pods). In addition to improving drainage and preventing root rot, a potting mix’s airy nature also makes container plants lighter in weight - which is a key consideration for a thriving vertical garden.

Garden soil, on the other hand, is heavier and denser. Its tendency to compact so easily and hold more water than needed can create drainage and aeration issues for your container plants.

Types of Potting Mix

For most potted plants, an all-purpose organic potting mix will work just fine. However, some plants may have special requirements ranging from excellent drainage to maintaining specific pH.

Luckily, there are potting mix options available that cater to these needs.

Organic potting mix

We ALWAYS recommend using an organic potting mix. Thankfully, there are plenty of options to choose from. When shopping, remember to check for the OMRI label (Organic Materials Review Institute) to ensure that only organic ingredients have gone into the blend. If you’re buying a mix that contains fertiliser, look for natural organic ingredients such as bone meal or blood meal.

Moisture-control potting mix

This blend contains ingredients with moisture control properties. Materials like sphagnum moss, coir, or vermiculite are added to the mixture to absorb and retain more water than standard potting mixes.

Orchid potting mix

The trouble with using a standard potting mix for growing your beloved orchids is that it retains too much water and too little air. An orchid potting mix is an airy, soilless blend of bark chips with some charcoal and perlite thrown into the mix to boost drainage. 

Succulent and cactus potting mix

Succulents and cacti flourish with lean soil with fast drainage. That’s why sand and perlite are key ingredients for desert plant-friendly potting mixes. When shopping for potting mixes for low-water plants, you may also come across variants like cacti, palm, and citrus mixed. These contain recycled forest products and pH adjusters like oyster shell meal and lime to keep the mixture from getting too acidic.

Now, Let’s Talk Potting Soil

Potting soil, or garden soil, contains ground-sourced soil as its main ingredient, making it denser and heavier than potting mix. (See? Totally different from potting mix!)

The formulations are designed to mimic high-quality natural soil with ingredients such as compost (for nutrition), peat moss (for structure), perlite (for water drainage), and vermiculite (for slow-release water retention). Since it contains dirt, potting soil is not sterile. It may contain soil-borne pathogens or weed seeds.

What is Potting Soil For?

The word “potting” might make you think otherwise, but potting soil is meant for raised beds and in-ground planting. Its composition and nutrient-rich compost additives are also quite useful in improving the health of your garden’s existing soil.

Potting Mix vs Potting Soil

Remember, each growing medium caters to a specific gardening environment and types of plants. While potting mix shines for its container-friendly weight, superior drainage, and aeration, potting soil is packed with nutrient-rich ingredients. If your gardening project includes a diverse set of plants, you may need both potting mix and potting soil. Also, depending on the types of plants, you may need more than one type of potting mix. 

Here’s a cheat sheet to help you choose the right growing medium for your garden.