To most of us, a soil is a soil is a soil when it comes to where the rose bush is planted. But to the educated gardener, selecting the proper potting mix, or medium, is vital to a plant's health and survival.

That's why there are so many different kinds of "dirt" or potting media to choose from, and as you can imagine, different prices. In fact, the best potting medium isn't dirt at all!

Choosing a potting medium can be terribly confusing, but the right mix is the starting point for achieving ongoing plant health. Whether it's the initial potting of a plant in a container, or the repotting of an indoor plant, we must first understand the difference between the myriad products on the market.

Basically, there are four types of potting mixes: 1) all-purpose, 2) premium, 3) professional, and 4) plant-specific. The base raw materials used in each dictate why some cost more than others. The raw materials can include composted bark, whether from pine, fir, spruce and redwood; nitrogen-rich compost; peat humus; sphagnum peat moss; and a lightening agent such as perlite (those little white things) or vermiculite.

It is important to look for soil that is even and consistent in texture. Stay away from anything that looks "clumpy" or has large, visible pieces of bark.

All-purpose potting mixes are fine for gardeners who like to add ingredients to customize their mix with plant food.

The main benefit of the premium mixes is that they aid in water drainage and aeration. These mixes include roughly 40% of the same base raw materials as the all-purpose types, but they also often include perlite and vermiculite to increase aeration and improve drainage.

Premium mixes also feature a wetting agent that helps provide more uniform water distribution in the soil. This means that the entire root mass will have water available after each watering.

Some premium mixes include fertilizer in either water-soluble or slow-release granular form. A slow-release fertilizer may be sufficient to feed a plant for 6 to 9 months.

The professional mixes, feature base raw materials that are more completely processed than in the premium blends. Additives to many professional mixes include sphagnum peat moss, vermiculite, perlite, composted bark finds, and a wetting agent.

Greenhouse growers, nursery operators, and gardening enthusiasts choose professional mixes because of the consistency of the product and their ability to better control how the plant is fertilized.

The fourth type of potting mix is the plant-specific variety. They generally tend to be premium mixes. Since different plants have different needs, each is manufactured specifically for that plant.

For instance, African violets, cactus, and succulents have unique root systems and watering needs. Therefore, special soils will allow for the proper aeration and soil chemistry for these plants.

The most amateur gardeners are best served by going with the premium mixes. The extra cost is worth it, as you get a perfect mix with all the measured base materials and components added by experts.

So next time you want to get down and dirty in selecting potting mixes, remember that they may look alike on the surface, but behave differently when they are the surface.

Sources:  This article was written by The Scotts Company with content assistance from Dr. Rosemarie Rossetti and Dr. Charles Powell, Certified Landscape Professionals.