Potting Mix vs Potting Soil: 4 Key Differences To Remember

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Looking for a potting mix vs potting soil comparison?

Both potting mix and potting soil are growing mediums for plants. However, they have different ingredients, characteristics, and benefits. 

In this article, we’ll explore the four key differences between conventional potting mix and soil, which one you should use, and two related FAQs

 Further reading

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Let’s begin.

Potting Mix vs Potting Soil: 4 Key Differences

Potting Mix

Potting Soil

Ingredients

A soilless mix usually made of peat moss, perlite, organic matter, fertilizer, etc.

Can contain soil, along with peat moss, perlite, fertilizer, wetting agents, etc. 

Characteristics

Light and fluffy with good aeration and drainage

Heavy and dense with poor aeration and drainage

Uses

Indoor plants, container gardening, and seed starting

Landscaping and composting

Longevity

Replace every 6 months

Refresh once a year


Let’s explore these differences in detail.

1. Ingredients

Here are the ingredients used in traditional potting mixes and potting soils:

A. Potting Mix

It’s a soilless medium that may contain:

  • Amendments like peat moss, perlite, coco coir, pine bark, and vermiculite.
  • Compostable organic matter.
  • Slow-release starter fertilizer like urea-formaldehyde.

Note: Conventional potting mix ingredients, like peat moss, perlite, and coco coir, require unsustainable harvesting and production practices that harm the environment.

B. Potting Soil

It usually contains ingredients like: 

  • Garden soil or topsoil. 
  • Organic matter like compost and decaying organic material. 
  • Synthetic or organic fertilizers.
  • Additives like pH balancing and wetting agents. 
  • Amendments like sphagnum peat moss, coco coir, perlite, and vermiculite.

Note: Peatlands are major soil carbon sinks, holding almost twice as much carbon as global forests. So harvesting peat or sphagnum moss releases the stored carbon dioxide into the atmosphere, contributing to global warming.

That’s why you should avoid using such harmful potting mixes and soils and go for eco-friendly products instead. 

2. Characteristics

Here are the defining characteristics of potting mixes and potting soils:

A. Potting Mix

Potting mix is usually light and fluffy.

Its ingredients and large particle size benefit healthy root and plant growth. 

Moreover, they facilitate soil aeration, nutrient retention (nitrogen, potassium, and phosphorus), and water drainage.

B. Potting Soil

Potting soil is noticeably heavy and dense due to the presence of garden soil or topsoil. It’s also naturally rich in organic materials and minerals. 

However, its density results in poor aeration and drainage, leading to soil compaction and plant root suffocation in container plants. 

That’s why potting soil comes with additives that improve airflow and drainage.

3. Uses

Here’s how potting mix and potting soil differ in their application:

A. Potting Mix

Thanks to potting mix’s aeration and water drainage abilities, you can use it for container gardening and potted plants or as a seed starter mix.

Its nutritional composition and large particle size mean gardeners need less mix per pot than potting soil.

B. Potting Soil

Potting soil has a dense structure that makes it ineffective for potted plants and seed starting. 

But you can use it to improve outdoor garden soil, fill garden beds, or for landscaping purposes.

Tip: Traditionally, potting soil isn’t sterile — it may contain pathogenic fungi or weed seeds that limit plant growth. But don’t worry; you can bake the bag in the sun to transform it into sterile potting soil.

4. Longevity 

Here’s how long potting mix and soil can last:

A. Potting Mix

If you’re using conventional potting mixes for a growing plant, you should change the mix every 6 months and repot the plant. 

Why?
Traditional potting mixes contain peat moss and other organic matter that eventually decompose, leading to soil compaction and nutrient depletion. 

Additionally, the regular watering of a potting mix can flush out its nutrients over time, making it unable to provide steady nutrition to plants.

B. Potting Soil

Unlike potting mixes, potting soils can last longer because they contain soil.

However, the soil can become compacted with overwatering and the decomposition of organic material. So, it needs to be refreshed with fertilizer or fresh potting soil once a year.

Potting Mix vs Potting Soil: Which One Should You Use?

Potting soil’s composition makes it suitable for outdoor plants. 

On the other hand, a soilless potting mix is a better choice for potted plants or a container garden because it:

  • Offers a good balance of moisture retention and water drainage for potted plants. 
  • Provides better aeration.
  • Contains essential nutrients for any container plant.

However, you must consider the environmental impact of using a conventional potting mix or soil before purchasing it. 

Why?
Potting soils and mixes containing vermiculite, perlite, peat moss, and coconut coir aren’t produced sustainably. Moreover, harvesting peat moss contributes to increasing atmospheric carbon levels.

So you should avoid using conventional, peat-based potting soils and mixes as they can harm your plants and the environment in the long run.

Instead, you can use an eco-friendly potting mix like Rosy.     

Rosy

Rosy offers a 100% natural and peat free Indoor Potting Mix that’s carefully designed to meet the needs of a growing plant.

It's a professional blend of materials like biochar, vegan compost, and beneficial microbes that boost vital nutrient levels and provide the best soil conditions for plant growth. 

The mix is purposefully different from a soilless medium completely devoid of life, making it better for your plants. 

What’s more?
Rosy’s mix contains natural, carbon-negative ingredients like biochar, which help remove carbon dioxide from the atmosphere — making it the most sustainable potting mix.

Simply add the soil mix directly to your pots or soil, and your garden will be bustling with life in no time.

2 FAQs on Potting Soil and Potting Mix

Here are the answers to two common questions on potting soils and mixes:

1. What Are the Types of Potting Soils and Mixes?

There’s a wide range of potting soils and mixes, including:

  • All-purpose or Indoor Soil/Mix: Has general nutrient and soil characteristics that's useful for any outdoor or indoor plant.
  • Outdoor Soil/Mix: Contains amendments to improve drainage and fertilizer for outdoor plants.
  • Organic Potting Soil/Mix: Made from natural materials, like compost and animal manure, without any synthetic ingredient like chemical fertilizers or pesticides. 
  • Seed Starting Mix: Light, low in nutrients, and drains easily — an ideal medium for seed germination and plant root growth.
  • Cacti and Succulent Soil Mix: Loose soil that usually contains amendments, like sand or gravel, to aid water drainage.

You can also make homemade potting soil using gardening soil or enriched topsoil (a blend of topsoil and compost) and a soil amendment, like biochar or sand. 

But remember to remove any weed seed present in the enriched topsoil before creating the blend so that it doesn't limit plant growth. 

2. Do Potting Soils and Potting Mixes Go Bad?

Yes, potting soils and mixes go bad as their organic matter decomposes with time. 

Peat blends, especially, become compacted as peat moss decomposes. So, they need to be refreshed or replaced periodically. Moreover, old potting soils and mixes can restrict plant growth.

However, a soil mix containing biochar, like Rosy’s Potting Mix, remains useful for much longer than conventional potting soils or mixes. This is mainly because biochar can last for at least hundreds of years without breaking down.

Wrapping Up

Traditionally, potting mix and potting soil are two distinct growing mediums with different properties and purposes. 

Potting mixes are suitable for potted plants, while potting soils are good for outdoor plants and landscaping. 

However, most potting mixes and soils are harmful to your plants and the environment. 
But not Rosy.

So if you’re looking for a high-quality, sustainable soil mix, you should try Rosy’s Indoor Potting Mix.

Why not grab a bag of this natural, peat-free mix to revitalize your plants?


Earth Positive Indoor Potting Mix

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We craft our mixes with the specific needs of houseplants in mind. Every blend contains all-natural, sustainable ingredients that optimize drainage, deliver plant-boosting nutrients and support a diverse community of beneficial fungi and microbes. It’s living soil in a bag — the perfect way to give your plants the TLC they need to thrive.
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