I wondered about this as well when starting my garden. Would it be wise to use potting soil in the ground? It works great for potted plants so it should also work for outdoor plants, right?
You can use potting mix in the ground because it has good texture to grow plants. It helps retain sufficient moisture and aeration for the plants. It’s sterile which prevents pests or diseases. The problem with using potting mix is that it’s expensive and you’ll need to add nutrients.
I’ve done some research to detail the advantages and disadvantages you need to consider before using potting soil in the ground.
Pro: It’s Sterile
One of the biggest perks of potting soil is that many brands sterilize the product before sale. This isn’t always the case, so make sure to read the labeling and get one that’s specifically marketed as sterile.
Sterilized soil is a planting medium that goes through a heating or chemical treatment process. Generally, manufacturers will bring the soil up to 200 degrees Fahrenheit.
The treatment is meant to kill any bacteria or pathogens that might be hiding in the soil. Natural loams are filled with life. While that’s not always a bad thing, it can put your plants at risk. Unsterilized soil may spread weeds or disease.
Sterilization is said to create a healthier environment for germination and plant prosperity.
Many gardeners choose to sterilize soil on their own. But let’s face it: That process can be too much of a hassle.
Mixing sterile potting soil in garden is a quick and easy way to prevent health issues from the onset. It won’t offer ongoing protection. You’ll still need to be proactive about keeping pests and diseases away. But, sterile potting soil is a fantastic way to start your garden off on the right foot.
Pro: Good Texture
The natural soil in your garden might look fine. However, it probably doesn’t have the right texture to support plants long-term.
Many soils are heavy in clay or soil. Clay is notorious for becoming hard and clumpy after heavy rain. It can restrict root growth, effectively confining plants in one place. Meanwhile, sandy soils dry out too quickly, preventing your plants from staying hydrated.
Potting soil can help alleviate some of those issues by improving its overall texture.
Potting soil isn’t actually soil at all. It’s a human-made concoction of organic materials. Each constituent is fine-tuned to offer great nutrient and texture benefits. Most potting soil products contain things like composted bark, peat moss, and small loose minerals.
The organic elements do a lot to improve the texture of your natural garden soil. When mixed in, they help improve water retention while also keeping things loose.
The minerals in potting soil work tons of magic, too. Things like vermiculite and perlite keep the soil aerated, allowing water and air to flow through the soil without any issues.
With all the human intervention involved with the creation of potting soil, expect a hefty price tag.
Potting soils can get quite pricy. Big-name brands are notoriously expensive, which can easily set you back hundreds of dollars if you want to fill a garden bed in the ground.
Manufacturers have to fine-tune the recipe to achieve a light and airy texture. Plus, they must source the ingredients.
Potting soil is of a much higher quality than standard garden soil. Packaged garden soil is basically the same as the dirt in your garden outside. The only difference is that it contains cheap organic materials like compost.
The ingredients in potting soil are a bit more premium. You have things like peat moss and crushed minerals. Those additives drive the costs up across the board.
Con: No Nutrients
Remember how we said that potting soil wasn’t real soil? Many in the gardening world refer to it as a “soilless mix” because it doesn’t contain any actual dirt. It’s a special formula of both organic and inorganic ingredients.
Many plants can grow in it just fine. But, it lacks some of the important nutrients that real soil provides.
The soil in your garden contains essential microorganisms. It’s a living ecosystem with tiny creatures that work to support your plants. Nematodes seek out and eat dangerous pathogens, while protozoa eat bacteria and enrich the soil.
Those microorganisms help to break down organic matter. Plus, they leave behind waste that infuses the soil with all the nutrients plants need to thrive. They play a pivotal role in the growth cycle.
Potting soil doesn’t have any of that. Even products that aren’t purposefully sterilized lack those essentials.
Con: Dries Out Quickly
Potting soil has a lot of great ingredients that help to retain water as long as possible. But, it might dry out faster than the stuff that’s sitting in your garden outside.
It all comes down to the formula, which can be a double-edged sword in some situations.
As mentioned earlier, potting soil is lightweight and airy to promote proper air and water flow. While good in most applications, it can speed up the evaporation process on hotter days. Heat can penetrate potting soil easier, allowing it to whisk away moisture.
Once the potting soil becomes dry, it’s an uphill battle to keep it moist. Potting soil contains peat moss, which is notoriously hydrophobic. It repels water, making rehydration a difficult task.
Con: It’s Not Suitable for Some Plants
Contrary to popular belief, potting soil is not a one-size-fits-all kind of product. While manufacturers do their best to make it as universally beneficial as possible, many plant species won’t grow well in it.
The somewhat picky nature of potting soil comes down to its pH level. One of the prime ingredients in the mix is peat moss. As we discussed earlier, peat moss has a lot of benefits. But it’s very acidic. The material usually hovers around a 4.4 on the pH scale. That’s pretty far away from neutral.
Now, some of that acidity gets diluted when other ingredients are added. However, it still brings the overall pH level down for potting soil. The acidic environment can wreak havoc on some plants. It can cause burns, stunt growth, and outright kill plants.
Can You Use a Mix of Potting Soil and Garden Soil?
It’s perfectly safe to use potting soil in the ground if you don’t mind the potential drawbacks.
That said, the best way to take advantage of its benefits is to mix it with garden soil. Whether you use garden soil from the ground outside or you buy it from your local garden center, mixtures offer the best of both worlds.
You get all of the organic goodness from garden soil with the texturizing perks of potting soil. Think of potting soil as an amendment. It adds nutrient-rich organic matter like peat moss while giving the soil a much-needed boost of aeration. The product can lighten your garden soil, making it more conducive to plant growth.
Potting soil and garden soil mixtures work well in raised garden beds, too. We recommend using a mix of one part potting soil to five parts garden soil. This ratio is a lot more affordable than a 50/50 split. Plus, it provides just enough potting soil content to improve texture throughout the bed.
When Should You Use Potting Soil?
Potting soils are best for container gardening. The unique formulas work well with the closed environment of a container. It provides all the organic matter your plants need while still simulating an all-natural medium like soil.
The enhanced texture promotes proper water drainage. If you use real soil, container plants can easily accumulate standing water. The vermiculite and perlite in potting soil help to prevent that issue.
Potting mixes are particularly useful for indoor gardens. The more sterile nature of these mixes ensures that you’re not bringing potentially harmful microbes into your home.