The first step to creating a flourishing planter is to choosing the best potting soil that will work with you. In order to grow healthy plants, a growing medium must be able to consistently supply water and nutrients as well as provide a structure in which your plants can take root. There are two categories of growing mediums to choose from; potting soil mixtures and potting soil-less mixtures.
Potting Soil Mixtures
Soil mixtures are often heavy and hold water and nutrients more easily than soilless mixtures. They are traditionally composed from soil, compost or peat moss and vermiculite or perlite. Composted manure can also be added to soil mixtures to increase water holding capacity and the abundance of nutrients. Soil mixtures do come with a few disadvantages. First, soil mixtures are prone to compacting, which can inhibit root growth, aeration, and cause poor drainage.
They are also more likely to contain weeds, seeds and disease, especially when they contain compost or unpasteurized soil (Source 2).
Potting soil mixtures are more appropriate for garden beds, or when needing to add extra organic material to an existing garden. Due to their weight, they are not appropriate for a movable container garden, but can be used in a stationary planter. Potting soil mixtures rarely require the addition of fertilizers due to the presence of pre-existing nutrients and minerals.
Potting Soil-less Mixtures
As the name suggests, soil-less potting mixtures do not contain soil. Instead, they are commonly made from sphagnum moss, peat moss, coconut coir fiber, perlite or vermiculite. This type of growing medium is sterile, offering the added benefit of being weed, seed, bacteria and disease free. For most gardeners, this offers the assurance that your seedlings will not be susceptible to attack by pre-existing diseases and organisms, allowing your plants to thrive.
Potting soil-less mixtures are lighter than traditional soil mixtures, which make them a good choice for raised container gardens which have the potential to buckle under heavy loads. Lighter soil also means less compaction, greater aeration, and consistent drainage). Because soil-less mixtures can be created from a variety of components, they allow you to customize the physical structure of the soil to meet specific plant needs.
Unlike potting soil mixtures, potting soil-less mixtures often lack the full range of nutrients necessary for healthy plant growth. For this reason additional organic fertilizers and micro-nutrients will need to be added to meet the nutrient needs of your plants. Careful attention must be paid to the level of salts present in fertilizers to prevent buildup in container gardens. It should also be noted that due to the ease with which soil-less mixtures drain, fertilizers and micro-nutrients may need to be applied regularly.
Best Potting Soil Mix
Now that you have the facts about best potting soil and best potting soil-less mixtures you might be wondering which to choose? The key to making the “right” choice for your garden is to look at the type of planter you are choosing and the type of plants that you wish to grow. If you’re growing in a small, raised container garden, you might want to try a soil-less potting mix for its light weight and sterile quality. However, if you’re growing plants that require a large proportion of organic matter in a stationary planter, a soil based potting mixture would probably be the right choice for your garden.
Take your time planning out your new container garden or redesigning a pre-existing one. You’ll be amazed by what the proper growing medium can do for your plants!