Home and Garden
Potting Soil vs. Potting Mix: What’s the Difference?
Potting mix and potting soil are 2 phrases that are generally used interchangeably to refer to any medium through which a plant can grow inside a container.
When you get specific though, potting soil refers to any growth media which contains dirt, either partially or completely, and which is used to grow plants in a container. Potting mix, however, is any soil-less media which was specifically developed to produce better gardening better results inside containers.
You’ll always find garden center products labeled as both potting mix and potting soil, so it’s better to know which one you are dealing with, as well as what their differences are. Following is a side by side look at both types.
In simple terms, potting soil is any container gardening media which has dirt in it. The dirt could be mixed in with other soil-less materials, or it could entirely make up the potting soil.
Potting soil is often nutrient rich because it has decaying organic matter and minerals, which offer steady nutrition to plants.
The potting soil can consist of dirt from the garden and one or more of the materials which are usually employed in the making of potting mixes. A potting mix can also be mixed with dirt, and it will, therefore, turn into potting soil.
Dirt or ordinary soil has a problem with containers. It will compact easily, blocking off air circulation and becoming water-logged, which make it less ideal as a growth medium.
On the other hand, potting soil is usually cheaper than potting mixes, and although the soil may be rich with nutrients, its density is a disadvantage and it makes it less ideal than potting mixes when it comes to container gardening.
Pros of Potting Soil
- Cheap. The first and best thing about potting soils is that they are generally cheaper than potting mixes. You can also create your own potting soil easily, either by using only soil from the garden or by mixing the soil with other materials.
- Can be fully organic. Potting soils can easily be 100% organic. You’ll have to look closely at a potting mix’s label to see what it’s made from, but pure garden soil can be totally organic. If you are eco-friendly, then this is definitely worth keeping in mind.
- Nutrient-rich. Unlike a potting mix that is usually enriched with organic matter, dirt is naturally rich in organic matter and minerals, which provides the nutrient needs of most plants.
- Long lasting. The soil is natural and so, it’ll last for a long time. Unlike a potting mix that’ll break down over time and become unusable, a potting soil will always be usable. All it might need from time to time is a little amending with fertilizer or organic manure.
- Easily compacts and gets water-logged. This is the main issue with natural soil and container gardening. While it might do well outside in the open, problems develop with soil once you pack it into a container. This disrupts the drainage of water in the container, leading to problems for your plant.
- Not fluffy enough. A good container gardening medium should be light and fluffy. This provides enough space for the roots to easily grow, as well as the free movement of air. A fluffy medium is very important and the ideal medium for container gardening.
- Low aeration. Potting soil allows much less air movement because it easily gets compacted inside a container.
- Not ideal for seed starting. Since natural soil is dense and its particles are tough and heavy, seeds always have a harder time germinating and growing inside it, than in a potting mix.
Potting mix in a strict sense is a soil-less growing medium, which got designed specifically for container gardening. It’s additionally made up of all the right materials to maximize the growth of plants.
A good potting mix includes pine bark or any other compostable organic matter, peat moss for water retention, plus perlite and vermiculite for nutrient, moisture, and drainage management.
The particles are usually larger in size than soil particles to offer the potting mix with better aeration. These particles are also lighter in weight, making it easier for roots to find their way.
Potting mixes can be custom mixed for particular plants or plants in particular stages of growth, such as a seed starting mix for seed starting. You can also get a cactus and an orchid mix, which both offer features to mimic either the cactus’ or the orchid’s natural environments.
Pros of Potting Mix
- Fluffy texture. By featuring a lightweight, fluffy, and easy to penetrate texture, potting mixes provide the easiest and best-growing media for roots.
- Good aeration and drainage. Potting mixes additionally have a better air-flow and water drainage than potting soils, which usually and eventually, become compacted.
- Good water retention. The addition of peat moss, perlite, and vermiculite, provide excellent water drainage, retention, and airflow properties, which is ideal for most plants.
- The right nutrient mix. With a potting mix, nutrients are available in the right combination, and unlike natural soil, there is no pH testing or amendments necessary.
- More costly. Since they need specific materials, potting mixes are generally costlier than potting soils, although the extra costs are often worth it.
- Lightweight. Potting mix is also lightweight and this can lead to problems in windy locations. The solution is of course to use heavier containers, but this often means extra costs as well.
- Breaks down over time. The organic parts of a potting mix will eventually break down over time and make the entire mix unusable as a growing medium.
Making the Right Choice
Choosing the right potting mix with all the right features for container gardening can mean the difference between a plant which is just struggling to survive, and one which is thriving. Following are the major features once more.
Potting mix and potting soil are two different types of growing media, with each one providing advantages as well as disadvantages.
It’s important that you always read the label to see what the potting mix or potting soil contains because that’s the only way you’ll be sure. And if the product offers no content list, then it might be a good idea to leave it alone.
A potting mix is definitely your best bet for container gardening, but if you are considering large-scale gardening, raised bed gardening, or filling in low spots in your garden, then you should probably use potting soil.