Guest Author - Connie Krochmal
If you choose not to purchase cacti potting mix, here is helpful information for mixing your own. Be sure that the final product is quick draining.
Most of these often start with a commercial or readymade product, such as a peat-based or coir-based potting mix. In the U.S., the typical brand names that are readily available would be the Fafard line, and the Metro-Mix line. Within these two brands are a wide number of specific formulations with each one being very slightly different. Examples would be Metro-Mix 366 Coir Mix with coir, and Metro-Mix 200, which contains sand.
The original soilless potting mix that these are based on was called Cornell mixes. In recent years, many variations on these have been created over the years.
Now, let’s look at some different mix-your own formulas. These different ingredients are combined in different ratios by volume.
For example, you can buy a bag of African violet potting mix and supplement this with some perlite to improve drainage. For this formula, use one part per volume of each ingredient.
For Christmas cactus, orchid cactus, and other epiphytic types, here is a sample formula with the amounts listed by volume: three parts organic potting mix, one part perlite, and one part sand. Or you could simply use half and half with one part potting soil and one part sand.
For desert cacti, you can make a simple one by adding two parts sand or grit to one part peat-based potting soil.
An all purpose mix would consist of one part sphagnum peat moss, two parts vermiculite, and two parts perlite. This is especially recommended for cacti and succulents that need a dry soil, such as desert cacti, agaves, and aloes. This formula creates a mix that feels coarse and sandy. Yet, it drains very quickly and doesn’t retain excessive moisture.
Another all purpose formula would be three parts of peat or peat substitute and one part sharp sand.
When you are buying a peat-based or coir-based soilless potting mix to use in your soils, do avoid ones that contain moisture retaining crystals. This is definitely not desirable for cacti and succulent formulas.
Soil-based potting soils are available. However, some commercial brands will be too heavy and poorly drained for cacti and succulents. It would be fine to start with this as a base and then combine it with porous, quick draining ingredients, such as perlite, vermiculite, and gravel.
