We got some feedback to our recent blog about potting soil, and many of you had the same question: what’s the difference between potting soil and container mix? As with so many of the topics we explore in this blog, the answer is a great big “it depends”. Different brands sell different mixes and it’s important to read the labels, but in general there are some key differences between potting soil and container mix that do affect how we might want to use them in our garden spaces. So let’s dig in and learn about potting soil, container mix, and the key differences between them.
Before we delve into the distinctions and differences between potting soil and container mix, let’s talk about soil. Soil is a natural product, the “dirt” or “earth” that the ground is made of. Soil itself is a mix of mineral elements, organic material, and various microbes and other small organisms. As we’ve discussed elsewhere, soil composition varies quite widely from place to place and getting your soil tested to find out what’s in it is a critical task for any gardener. Plants evolve to work with the soil conditions of their native place, whatever those happen to be, and this in part explains the diversity of plants found throughout the world.
Garden Soil, Potting Soil, Container Mixes, and More
From here on out the definitions get murky. You’ll see many products advertised as “garden soil”, which are generally mixes of natural soil, compost, and other soil amendments intended to create ideal conditions for plant growth. What exactly goes into any commercial garden soil product varies by both product and manufacturer, so read the labels and ask folks at your local cooperative extension or local garden store to learn which ones might be best for your needs. Buy from reputable sources as well—garden soil products are very often unregulated or poorly labeled.
“Container mix” is different than both garden soil and natural soil. Different container mixes are formulated for particular purposes. Seed starting mixes tend to be light and contain little if any actual soil, but rather things like coconut crore, sphagnum moss, perlite, vermiculite, and fertilizers. This creates a light medium that holds water well while also promoting air flow and makes it very easy for seeds to sprout and go through their initial growth phase. Most of the time seed starting mixes aren’t meant for long-term plant growth, so timely transplanting is important as the seedlings mature. Container soils or potting mixes take some of the lightening ingredients of seed starting mixes like crore, sphagnum moss, and perlite/vermiculite and combine them with soil, compost or fertilizers, and sand in order to create a medium that’s light enough to drain well in a container but can still support fully grown container plants. As with many other soil or potting products, container mixes come in a wide variety of formulations designed for particular plants or particular conditions. As always, read the label and ask an expert—you can email us if you have questions but we recommend talking to someone who knows your local gardening conditions as well.
Selecting the Right Type of Potting Soil
So which of these is the right choice for you? Well that depends on what you’re doing. Seed starting mediums are great for that purpose, but for fully grown plans we recommend a more robust type of soil. Potting or container mixes are a good choice for any container application—we’ve eve used them successfully in smaller raised bed setups. They do however require regular refreshing to replace lost nutrients and maintain their lightweight texture. Garden soil, whether purchased from a garden supply store or improved with soil amendments on-site, is a great choice for larger raised beds and in ground gardening. We really recommend trying to work with the soil you have via natural soil amendments and native plants.
We know this is a complex answer to a complicated question, so we encourage you to get in touch with your local cooperative extension or garden club/garden supply for more information. And feel free to email us with any questions—Gardzen is all about community and we love to hear from you!
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