Growing Media

We commonly refer to whatever supports a plant’s root system as “soil.”  It is actually a growing medium. A good growing medium should be porous, that is, have little spaces between the soil particles, and ideally, half of the pores should be filled with water and the remaining half filled with air, or oxygen.

Potting mixes for indoor plants are sterilized, and therefore, they do not contain insects, eggs, diseases, fungi, spores or other pests.  This mix is light enough for good drainage and aeration of roots, yet heavy enough to retain moisture and nutrients.

pH

The acidity or alkalinity of soil and growing media is important to all plants, because it determines how well a plant can absorb the minerals from the media. The pH scale ranges from zero to 14, with seven being neutral. From zero to six is acid, from eight to 14 is alkaline. In general, tropical plants prefer a pH of 5.5 to 6.5, which is slightly acidic. High alkaline content will cause a plant to lose leaf color and exhibit stunted growth. High acid content will cause wilting and abscission. Soil and water pH should be tested with a pH meter or litmus paper to determine whether adjusting is necessary.