Potting Soil Vs Potting Mix: What To Know

Potting Soil Vs Potting Mix: What To Know

Last Updated on July 6, 2022

A conundrum for any beginner gardener is the potting soil vs. potting mix debate. While you might assume that potting soil and potting mix are the same thing, they’re actually quite different. 

Why are potting soil and potting mix used interchangeably?

Although potting soil and potting mix are different, they are often used interchangeably, even by authentic gardening sites online, which is why it can be confusing to tell the difference between them.

With the above in mind, let’s explore what you need to know about potting soil vs. potting mix. After reading this article, you’ll know which one to use for your gardening requirements. 

What Is Potting Soil?

What Is Potting Soil? 

Potting soil is a mixture of materials that help plants to thrive. It can contain soil and sometimes even contains sand. Potting soil also contains minerals and organic matter. It tends to be thick in consistency.

When Is Potting Soil Used?

You should use potting soil for outdoor gardening, such as when planting plants straight into the ground instead of in containers. However, it’s also a good idea to use it when planting plants in pots.

When using it, make sure you add amendments to it so that you improve how well it drains water. This is because potting soil can be dense, which causes it to become compacted.

Although you might want to use potting soil for various gardening tasks, you shouldn’t use it in all your raised beds or flower beds, unless you have old potting soil that you want to get rid of.

This is because potting soil is expensive and it doesn’t contain enough nutrients to feed plants every season. 

Usually, the potting soil mixes on the market only last for about one growing season before their ingredients start to degrade. 

What Is Potting Mix? 

What Is Potting Mix? 

Potting mix is a blend of ingredients that help container flowers and plants to grow healthier. It doesn’t contain any soil, nor does it contain any pathogens or bacteria, both of which can be found in potting soil.

Potting mix contains ingredients such as peat moss, sphagnum moss, pumice, perlite, and bark. It can sometimes also contain fertilizer to boost the growth of plants when growing them in pots.

Potting mix is much lighter and fluffier than potting soil. This prevents it from becoming compacted. 

When Is Potting Mix Used?

You should use a potting mix whenever you’re growing plants in containers. This is because potting mixes are specially formulated for container gardening.

Potting mixes also come in different variations for different plants, such as cacti potting mixes, that give specific plants the nutrients they need.

Potting mix should be used instead of potting soil when you’re growing plants in containers as a result of how it provides them with the correct soil conditions, such as drainage and aeration. 

Potting soil becomes compacted in containers, which isn’t ideal for plants as it prevents air circulation and can lead to too much water that damages plant roots.

Potting Soil vs. Potting Mix: What Are Their Main Differences? 

Potting Soil vs. Potting Mix: What Are Their Main Differences? 

Potting soil and potting mix share some similarities, but they’re actually quite different and need to be used for different gardening tasks. Let’s take a look at their main differences.

Ingredients

Potting soil contains mineral and organic matter, and sometimes it contains dirt. To infuse the potting soil with more nutrients for plants, potting soil usually contains compost.

By comparison, potting mix doesn’t contain any soil. This is why you’ll sometimes see that it’s referred to as a “soilless mix”. 

There are some potting mixes on the market that contain fertilizer to increase their nutrient content. Generally, though, potting mix contains various ingredients to boost soil drainage and aeration, such as peat moss, bark, vermiculite, and perlite.

Consistency

Potting soil is quite dense, which is usually as a result of how it contains compost.  By comparison, potting mix is designed to be light and fluffy. This encourages greater air circulation and water retention in containers.

Sterility

Potting soil can contain various ingredients that can damage plants, such as weed seeds and pathogens. This is as a result of how it contains dirt.

A potting mix doesn’t contain any soil, so it’s free from weeds, pathogens, and insects that can cause diseases in container plants.

Use For Seedlings

If you’re growing seeds, you shouldn’t use potting soil to encourage their growth. This is because of how it’s thicker in consistency and doesn’t contain enough aeration for seeds to grow.

A potting mix is more suitable for seeds as its ingredients promote air circulation and soil drainage. 

Amendments

Potting soil needs to be amended with other ingredients to make it more nutritious for plants. This is the case even if you’re using potting soil that contains a high nutrient content in the form of compost.

But, the amendments you need depend on the plants you’re growing in the soil and what nutrients are required for them to thrive. 

As for potting mix, it usually doesn’t require amendments, although you will find some brands that combine fertilizer with their potting mix blends to increase their nutrient content.

Depending on the type of potting mix you have, such as if it hasn’t been designed for a specific type of plant, you can add amendments to it, such as compost or peat moss. 

What To Look For In A High-Quality Potting Soil 

What To Look For In A High-Quality Potting Soil 

When shopping for potting soil, make sure it has some important features to ensure it will benefit your plants.

  • Check that the potting soil has drainage-boosting ingredients, such as slate or perlite. 
  • If your plants require a boost of nutrients, you should look for ingredients such as rice hulls and worm castings. 
  • Check its pH level. A quality soil mix will indicate if it’s pH-balanced for certain plants, such as plants that love acidity, or if it’s neutral or alkaline in nature.

Best Potting Soil 

Here are two quality potting soils you can purchase.

  • FoxFarm Ocean Forest Potting Soil: This is a versatile potting soil that can be used for indoor gardening as well as outdoor plants. It has an adjusted pH that ensures your plants can take up fertilizer effectively. It’s light in texture, which makes it useful for indoor plants. It contains ingredients such as crab meal, earthworm castings, sandy loam, and sphagnum peat moss.
  • Black Gold Organic Potting Soil: Since this Black Gold organic potting soil contains rich, loamy soil, it can be used in all gardening applications. It’s OMRI-listed as organic and has been enriched with ingredients such as pumice, perlite, organic fertilizer, and earthworm castings. 

What To Look For When Purchasing Potting Mix

8What To Look For When Purchasing Potting Mix

When shopping for potting mix instead, here’s what you should look for in products so you get a high-quality foundation for your plants. 

  • Potting mix should be fluffy and lightweight. 
  • Check that it contains ingredients such as perlite, pine bark, and peat moss. 
  • If the product contains fertilizer, this should be a controlled release fertilizer that will feed plants over the period of several months. 
  • If you want to ensure that the soil in your hanging baskets won’t dry out too quickly, wetting agents should be added to the potting soil. 

Best Potting Mix

Here are some potting mixes that you should consider if you need to boost the health of your container plants.

  • Espoma Organic Potting Mix: This is a versatile potting mix that’s ideal for use on all types of potted plants. It contains a blend of humus, perlite, sphagnum peat moss, kelp meal, earthworm castings, and alfalfa meal. It can be used for starter plants or when transplanting a plant into a new container.
  • Miracle-Gro Potting Mix: This product encourages the growth of plants in containers that are either indoors or outdoors. It feeds plants for a period of up to six months and ensures that they can grow healthier and bloom more beautiful flowers. It contains ingredients to nourish plants and ensure a balanced soil, such as peat, sphagnum peat moss, coir, perlite, and a wetting agent. 

Can You Make DIY Potting Soil Or Potting Mix?

Can You Make DIY Potting Soil Or Potting Mix?

If you’re a DIY gardener, you might want to make your own potting soil or potting mix.

You must ensure that you collect all the ingredients you need to make it nourishing to plants and to encourage healthy soil, such as with ingredients that promote soil drainage and aeration.

It will take some time, however, and you might have to do a bit of trial and error to get it right. An easy recipe for potting soil is to add equal parts peat moss, compost, perlite, and garden soil.

For potting mix, mix together sphagnum peat moss and vermiculite. Instead of vermiculite, you can use perlite. 

The benefit of making your own potting soil or potting mix is that you’ll know exactly what ingredients it contains, therefore you’ll be able to amend it according to your gardening needs.

Here are some points to bear in mind when making your own DIY potting soil or potting mix.

  • Always add moisture. You’ll need to add an ingredient that maintains moisture to your potting soil or potting mix. You can make use of coconut coir, compost, or peat moss. If you’re using peat moss, it can become too dry so you will need to add a wetting agent, such as by putting a few drops of dishwashing soap in one gallon of water. 
  • Remember to add a soil-draining ingredient. If you want to use sand, it should be coarse builder’s sand as it won’t be too dense to prevent aeration in the soil. Alternatively, add perlite and vermiculite. 
  • Add limestone to reduce acidity. If you’re adding peat moss to a DIY potting soil or potting mix, it can cause it to become acidic so you’ll need to add 10 pounds of limestone to every cubic yard of peat moss mix. If, on the other hand, your plants thrive in acidic soil, you don’t have to worry about lowering its acidity. 

What About A DIY Potting Mix For Seeds?

What About A DIY Potting Mix For Seeds?

If you’re growing seeds, a DIY potting mix is better than potting soil, as we discussed earlier in this article.

To ensure you give your seeds a good chance of surviving and thriving, you need to consider the following things.

  • You don’t need many ingredients to make a potting mix for seeds: mix together compost, perlite, and coir. 
  • Perlite is especially important not to neglect in your potting mix. This will improve its structure and promote drainage.

Related Questions 

What is garden soil?

What is garden soil?

Garden soil is a mixture of topsoil and sand that also contains various organic materials, such as composted bark and composted manure.

Can potting mix contain chemical fertilizer for edibles?

If you’re growing your own herbs and vegetables, make sure you avoid purchasing a potting mix that contains chemical fertilizers. Rather opt for a natural, organic potting mix and check its label to ensure that it’s safe for use on edible plants. 

Conclusion 

If you want to plant new flowers or plants, either in the garden or in containers, you will naturally wonder if you should purchase potting soil or potting mix. 

In this guide, we’ve featured some of the most important differences between them and which one to use depending on the gardening task you want to achieve. 

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