Bagged Soils for Gardening Explained

In This Blog

    Do I need a potting mix or raised bed soil?

    Here’s a quick read to help you make informed decisions when buying bagged soil products so your results are as green and lush as possible (and you don’t pay for something you don’t need.)

    Buying bagged soil at the garden center or big box store can be confusing. Different brands, product names, and descriptions can overwhelm a new gardener–not to mention the price variance.

    First, remember this general rule: the smaller the container or bed, the lighter the soil should be. Planters and pots need a light and airy potting mix. Raised beds can handle soil that is somewhat heavier. The higher density of topsoil is fine for filling in low spots in the yard or adding to the garden.

    Bagged soils offer convenience and a tailor-made product, but they are expensive. If you need a lot of soil or compost, for example, enough to fill several raised beds, consider having it delivered in bulk. Many nurseries and landscaping companies will bring it by trailer or truckload, saving you money and eliminating the need to dispose of dozens of plastic bags.

    Choosing the Right Soil

    Picking the general soil type you need is fairly straightforward. Choose a potting mix for potted plants and garden soil for mixing into your veggie patch. But, can you use potting mix in your raised garden beds? The answer is you could, but you’d be wasting money. It would be like driving a new car in a demolition derby.

    Here’s a breakdown of the typical uses for each common kind of bagged soil product.

    Potting mix

    This is the stuff we fill our deck planters with. Potting mix is formulated to be less dense, hold moisture, and stay loose. Using potting mix avoids the soil compaction problems common to large containers. Many potting mixes have fertilizers added in, so you won’t need to worry about plant nutrients for a while, perhaps even the entire season.

    Some potting mixes are labeled as organic, meaning that the ingredients used to make them have to meet certain standards. They’re more expensive, so many gardeners use organic potting mix only for plants intended for the dinner plate, and use standard potting mix for flowers and bigger planters.

    Topsoil

    This is the soil scraped off the top few inches of ground. It’s commonly screened to remove large rocks and roots (your mileage may vary depending on brand) and is inexpensive. Use this for filling holes in the yard or to fill in thin spots in the garden, mixing it with the existing soil. It isn’t suitable for containers and should be mixed with other amendments for raised bed use.

    Garden soil and raised bed garden soil

    Most of these products are designed to be mixed with native garden soil at about a 1:1 ratio. Soil marketed specifically for raised bed use won’t need to be mixed.

    These soils often contain some ingredients, like compost or manure, to lighten their density. Use them to improve garden beds or for filling raised beds. They are often too heavy for container use.

    Specialty soils

    Small bags of soil formulated for specific plants are commonly available. Examples include orchid soil and cactus soil. Save yourself the work of recreating the perfect mix by using these if you only need a small amount.

    Reading the Ingredient Label

    Bagged soils are not all created equal, and their contents vary widely. In fact, most bagged soils don’t contain any actual soil at all! Don’t worry; they’ill grow plants just fine when used appropriately.

    Reading the ingredients will let you know what’s in the bag. Understanding each ingredient’s purpose helps to make the decision on which product to choose.

    Aged Forest Products

    Regardless of the name (and there is no standardization or definition), some sort of forest product is a large component of most bagged soils. Depending on the quality of the product, these forest-based materials can be halfway to compost and ground up very finely, or you may find large sticks, chunks of bark, and discernable wood chips in the bag. You pretty much get what you pay for.

    When properly prepared, these aged wood products (sometimes called wood fines) are almost unidentifiable. They should blend in and look like soil.

    Peat Moss

    Opinions on using peat moss are diverse, but it is an ingredient commonly found in bagged soil mixes, especially potting mix. Peat moss is added to bagged soils to keep them light and aerated and to help them hold onto moisture.

    Most peat moss used in North America comes from Canada. If you’re concerned about sustainability, look for the Veriflora Responsibly Managed Peatlands program seal on the bag. Other alternatives to peat moss exist, including tree bark, aged wood fines, and coco coir. These materials have their own unique sustainability concerns.

    Perlite

    You’ve likely seen perlite before. It’s those fluffy, popcorn-like balls of snow-white material in potting soil. It’s actually a type of volcanic rock, even though it looks and feels like foam.

    Perlite breaks up the density of soil mixes and keeps them light and airy. Compacted soils don’t drain well, and they don’t allow oxygen to reach the roots.

    Fertilizers

    Depending on the product, fertilizers can be present as natural sources like worm castings, bat guano, kelp meal, alfalfa meal, and manure. In non-organic bagged soils, fertilizers are likely to include synthetically prepared nitrogen, phosphorus, and potassium sources. If labeled as a slow-release fertilizer, some nutrients are usually coated with a polymer to slow down their breakdown and absorption over time.

    Compost

    There really isn’t a standard for the gardening industry regarding what qualifies as compost. Part of the reason for this is that compost can be made from a nearly endless variety of ingredients. As long as it was made (at least partly) by the microbial breakdown of plant and animal materials, it counts. Some discount manufacturers may play fast and loose with even that definition.

    In general, compost in your bagged soils is a good thing. You can also buy bags of straight compost. Read the ingredient label on the bag to see what it was made from.

    Lime

    Lime is often added as a pH adjustment to ensure a relatively neutral soil. Dolomitic lime is a common ingredient which raises the pH of acidic soils and adds a bit of calcium and magnesium.

    Manures

    We know what manure is, but in our bagged soils, we want it to be aged or composted manure, not fresh. The source animal isn’t as important. If you open the bag and it smells like a barnyard, you didn’t get aged manure, and it’s too fresh to apply directly to plants.

    While there are nutrient variances between different animals’ manure, we care mostly that the manure isn’t fresh but is broken down enough to be unrecognizable in the bag. If that’s the case, then it’s good stuff.

    Conclusion: Maximizing Your Garden’s Potential with the Right Bagged Soil

    Choosing the right type of bagged soil is crucial for the success of your gardening projects, whether you’re planting in small containers, large planters, or raised beds. By understanding the specific benefits and appropriate uses of each soil type—from potting mixes to topsoil and specialty blends—you can make informed decisions that will enhance the health and beauty of your plants. Always consider each soil product’s composition and intended use, and remember that the best results come from using the right soil for the right situation. Happy gardening!

    Shopping Cart
    Scroll to Top