Houseplant Basics 101-Soil

Photo provided by anitapatterson

The quality of the potting soil you use can mean the difference between life and death for your houseplant. This means that you will want to invest in a high-quality potting soil that offers the correct balance of water and oxygen. This balance is important because the soil must be able to retain moisture long enough to sustain your houseplant between waterings as well as allow for proper drainage.

Be sure that you do not reuse potting soil from the pots of previous houseplants. If the houseplant died because of pests or disease, the potting soil could be contaminated. Even if the houseplant died because you let it dry out one too many times, do not reuse the soil. The soil may have far to few pore spaces, which are pockets of open spaces that can be filled with water, to sustain a new houseplant. As soil decomposes, it starts to lose pore space and it becomes too dense for air to infiltrate and for roots to grow properly. However, your pots can be reused. Just be sure to scrub them clean and then soak them in a solution of 10% bleach and water.

Potting Mix vs. Soil Mix

Soil is the term that most people use to describe the black medium in which we pot plants. But the truth is that most of the soil to which we refer is actually soil-less. It is completely free of what we traditionally think of as garden soil. It looks like rich garden soil and it even smells like it, but it is completely different.

Most potting mixes contain at least one of the following material: peat moss, vermiculite, perlite, sand and lime to neutralize the peat moss, bark, pumice or compost. On the other hand, soil mixes contain a blend of soil. So when you’re looking for soil, be sure to read the bags carefully and choose a high quality soil-less potting mix.

Specialty Potting Mixes

There are some houseplants that require special potting mixes like orchids, cacti and African violets. Since these houseplants are so popular, distributors have come up with special commercial blends of each type.

Orchid mixes: To the uninitiated, this planting medium might look unable to sustain anything other than a beaver. Many contain two or three types of bark, coarse sphagnum peat, fine grade pumice and sponge rock. It is a rather odd combination, but it is one that serves an important purpose.

Some species of orchids grow on trees in their natural habitat. These orchids are referred to as epiphytic plants, which are those having their roots exposed to the air. One of the reasons that orchid mixes contain bark and moss is to allow the air to move freely through the medium. This air movement allows the roots of an orchid to absorb moisture and nutrients from the humid air.

Cacti mixes: Even someone who doesn’t know much about cacti knows that these plants prefer dry soil. It should therefore come as no surprise that the standard potting medium for cacti is composed of coarse sand, potting mix, peat and perlite. Although the formula varies from one commercial mix to another, all cacti mixes are designed to provide rapid drainage.

African violet mixes: African violets like a soil that is light, loose and porous. Most African violet mixes consist of three parts peat moss, two parts vermiculite and one part perlite. Lime is also often added to bring the pH level to the 5.8 to 6.0 range. African violets hate having their roots sitting in water, so the loose, porous soil is important for the health of these plants.

What is your favorite potting soil to use with your houseplants? Leave me a comment and share.