Curious about the differences between topsoil vs potting soil?
These soils are distinct gardening resources, and understanding their different characteristics and applications can help you bring out the best in your garden.
For starters, topsoil is the natural top layer of the earth in a field or garden bed, while potting soil is a blend of ingredients specifically crafted for growing various types of plants.
So, which is the right soil for you?
This Article Contains:
(Click on a link to jump to a specific section)
- Topsoil vs Potting Soil: 4 Key Differences
- The Best Potting Soil for Container Gardening: Rosy’s Indoor Potting Mix
- 2 FAQs on Using Topsoil and Potting Soil
Topsoil vs Potting Soil: 4 Key Differences
Can contain soil, decaying organic matter, and compost
May or may not contain soil, peat moss, perlite, wetting agents, etc.
Coarse and heavy
May be light or heavy
Lasts for around eight years
Lasts up to two years
Let’s explore these differences in detail:
A noticeable difference between the two soils is their composition.
Topsoil is natural garden soil that’s rich in nutrients.
It may contain materials like:
- Compost or manure (compost amended topsoil is called enriched topsoil).
- Decaying organic matter.
- Sandy soil.
Note: Topsoil from different regions can have varying compositions based on the area’s climate and existing soil conditions.
B. Potting Soil
Traditional potting soil may or may not contain soil.
It’s commercially manufactured to meet specific plant requirements and usually contains ingredients like:
- Garden soil.
- Amendments like peat moss or coconut coir.
- Materials like perlite or vermiculite for drainage.
- Organic matter like composted sawdust or mulch.
- Fertilizer like worm castings.
The ingredients can vary depending on the use of the potting soil, like whether it’s used for seed starting or plants like orchids.
Moreover, ingredients like peat moss, coconut coir, perlite, and vermiculite have a high-carbon footprint — they contribute to increasing greenhouse gas levels.
That’s why it’s best to use sustainable and eco-friendly potting soils, like Rosy.
Note: Potting soil is often confused with potting mix — which is strictly a soilless medium.
Read more about potting mix vs potting soil differences in our detailed article.
Here are the key characteristics of topsoil and potting soil:
Topsoil contains beneficial soil microbes that aid nutrient availability and uptake.
But the soil is coarse and heavy, owing to its composted matter, clay, and rock particles.
This means that although topsoil is fertile, its properties, like low drainage and aeration, aren’t suitable for plant growth. It may retain moisture and suffocate plants.
However, topsoils’ characteristics depend on the type of soil (loam, clay, sandy). And since it's mostly natural soil, it can also contain weed seeds or disease-causing pathogens commonly found in soil.
Quick Tip: Sterilize topsoil and test the pH before using it as gardening soil.
B. Potting Soil
Potting soil that contains garden soil is typically heavy and dense.
As a result, it has soil amendments to improve aeration, drainage, and moisture retention. It also has added nutrients and organic material to support plant growth.
On the other hand, true potting soil is soilless. It’s light and fluffy — providing suitable growing conditions for a container garden.
But regardless of the type of potting soil, you won’t have to sterilize it since its production involves chemical processes that eliminate most plant diseases and weed seeds. So, you’ll mostly be using sterile potting soil for your plants.
Here’s when you need to refresh topsoil and potting soil:
Bagged topsoil can last for up to 8 years when stored properly.
However, it needs to be amended with fertilizer or compost when applied to gardens. This helps enrich the soil with nutrients and organic material, creating a supportive environment for plant roots.
B. Potting Soil
Unopened bags of potting soil can last for six months before their quality reduces.
But you need to replace potting soil in containers every one or two years or refresh old, used potting soil with 50% fresh potting soil.
Peat moss in traditional potting soils lasts for about two years in the soil before decomposing. Once it decomposes, the soil compacts and becomes unsuitable for plant growth.
On that note, peat free potting soils remain viable longer than traditional soils.
Here’s how topsoil and potting soil differ in their applications:
Topsoil is more of a soil conditioner than a growing medium.
It can be used to:
- Improve flower bed soil.
- Increase the volume of raised bed soil.
- Enrich existing garden soil.
Fill dirt in new gardens.
However, if you’d like to use topsoil as gardening soil for cultivating vegetable gardens, you can create a 50-50 soil mix with native soil for improved aeration and drainage.
But why shouldn’t you use it by itself as a growing medium?
Due to its poor soil structure, topsoil isn’t a good medium for plant roots or even flower beds.
Its poor drainage leads to excessive water retention and root suffocation. But when added to native soil, these qualities are improved enough to sustain plant growth.
And if the topsoil contains clay or sandy soil, it may need amendments for growing plants. In that case, you’ll have to add more organic matter to loosen the soil and promote drainage.
B. Potting Soil
Potting soil that contains soil is better for growing vegetables in large outdoor pots or raised beds.
On the other hand, soilless potting soil is perfect for a container garden or indoor plant — like a fern or cactus. It offers beneficial properties like aeration and water drainage to support plant growth.
Moreover, potting soil comes in different types to suit various growing plants. For example, a good potting soil for succulents will have sandy soil or amendments for enhanced drainage.
However, remember that traditional potting soils contain peat moss, perlite, and other unsustainable ingredients. Their use has short-term benefits for gardening but long-term consequences for the environment.
So, it’s better to use eco-friendly potting soils, like Rosy.
The Best Potting Soil for Container Gardening: Rosy’s Indoor Potting Mix
Rosy provides a high-quality Indoor Potting Mix made from natural and sustainable ingredients.
This soil mix is a professionally designed blend of biochar, vegan compost, and beneficial endomycorrhizal fungi. It improves soil aeration, promotes helpful soil microbes, and makes gardening earth-friendly by reducing carbon dioxide levels.
Just add the potting mix to your indoor pots to see your garden thrive in no time.
2 FAQs on Using Topsoil and Potting Soil
Here are two common queries about topsoil and potting soil:
1. Can Topsoil and Potting Soil be Mixed?
Yes, you can mix the two if you’d like to use topsoil for your container plants or raised beds.
Mixing them will enhance the topsoil’s structure, making it more viable for potted plants. Additionally, topsoil’s high organic content will add nutritional value to the potting soil.
You’ll need at least 30% fresh potting soil to create a fertile soil mix. You’ll also need to apply worm castings or fertilizer around the base of the plant.
2. Is Organic Potting Soil Better?
Organic potting soil is free from synthetic fertilizer and inorganic amendments, like perlite or vermiculite.
These inorganic ingredients lead to heavy greenhouse gas emissions. Moreover, they decrease soil fertility in the long run and contribute to environmental pollution.
So, organic potting soil is safer for your plants and the environment, offering better soil productivity than traditional potting soil.
Understanding the difference between topsoil and potting soil can help you lay the foundation for a happy and healthy garden.
Topsoil is excellent for landscaping and filling spaces, but potting soil is better if you need a growing medium for container plants.
And if you want an Earth-positive soil that’s beneficial for any potted plant, you’ll love Rosy's Indoor Potting Mix.
Why not try a bag of Rosy today to nurture your houseplants and the planet?