Potting mix and potting soil are terms often used interchangeably, but there are some differences between the two.
Potted plants, whether indoors or outdoors containers, need a good potting soil to thrive. As we approach the growing season you'll want to know the difference so you can choose the best medium for your seedlings and outdoor containers. Remember to look for the word "soil" on the bag - if it's on the bag it is potting soil, not potting mix.
Composition
Potting mix: Typically consists of a blend of organic materials such as peat moss, composted bark, coconut coir, perlite, and vermiculite. It may also contain added nutrients and fertilizers but does not contain any dirt or earth. As such, a bag of potting mix is a lot lighter than potting soil. Note that peat moss harvesting is not good for the environment (read our article about peat here), so look for potting mixes that don't contain peat.
Potting soil: Often contains a higher proportion of natural soil or topsoil along with organic matter like compost, peat moss, or aged manure. It may also contain sand or perlite for drainage. Potting soil is not sterile like potting mix.
Drainage and Aeration
Potting mix: Generally lighter and fluffier, providing better drainage and aeration for plant roots.
Potting soil: Can be heavier due to the presence of soil, which may lead to less efficient drainage and aeration.
Nutrient Content
Potting mix: Often formulated with specific nutrient blends or slow-release fertilizers to provide essential nutrients for plant growth.
Potting soil: May contain fewer added nutrients and rely more on natural components like compost or aged manure for nutrition.
Uses
Potting mix: Ideal for container gardening, indoor plants, seed starting, and plants that require well-draining soil.
Potting soil: Suitable for outdoor gardening, planting in-ground, and situations where soil improvement or amendment is desired.
Composition
Potting mix: Typically consists of a blend of organic materials such as peat moss, composted bark, coconut coir, perlite, and vermiculite. It may also contain added nutrients and fertilizers but does not contain any dirt or earth. As such, a bag of potting mix is a lot lighter than potting soil. Note that peat moss harvesting is not good for the environment (read our article about peat here), so look for potting mixes that don't contain peat.
Potting soil: Often contains a higher proportion of natural soil or topsoil along with organic matter like compost, peat moss, or aged manure. It may also contain sand or perlite for drainage. Potting soil is not sterile like potting mix.
Drainage and Aeration
Potting mix: Generally lighter and fluffier, providing better drainage and aeration for plant roots.
Potting soil: Can be heavier due to the presence of soil, which may lead to less efficient drainage and aeration.
Nutrient Content
Potting mix: Often formulated with specific nutrient blends or slow-release fertilizers to provide essential nutrients for plant growth.
Potting soil: May contain fewer added nutrients and rely more on natural components like compost or aged manure for nutrition.
Uses
Potting mix: Ideal for container gardening, indoor plants, seed starting, and plants that require well-draining soil.
Potting soil: Suitable for outdoor gardening, planting in-ground, and situations where soil improvement or amendment is desired.
While both potting mix and potting soil serve as growing mediums for plants in containers, the choice between the two depends on factors such as the type of plants being grown, drainage requirements, and the specific needs of the gardening project.