Can I Use Cactus Potting Soil for My Orchid?

Cacti Potting Mediums

• Cacti roots easily rot, and therefore should be potted in a well-drained soil combination. Equal parts of potting soil, sand and peat moss make good growing conditions for cacti. When using potting soil, be sure to obtain a soil without wood shavings because they tend to hold too much moisture in, while the main objective is to provide good drainage. Coarse building sand is recommended rather than sea sand, also for drainage reasons. Building sand has less salt, a mineral that could be detrimental to the cactus, causing dehydration of tissue or "salt poisoning." Adding a small amount of gravel to the soil combination is also a good way to ensure drainage. A very small amount of perlite is sometimes used in place of the gravel, as it allows drainage yet holds some moisture for the plant roots. The danger lies in using too much, as it can hold in more moisture than the cactus roots can handle, causing them to rot.

Orchid Potting Mediums

• Orchids need a well-drained potting medium, too, but require that the medium holds some moisture for the roots. Unlike cacti, they do not do well in a medium that uses soil, and therefore cannot thrive in the same mediums as cacti. Soil prohibits circulation of air at the plant roots. Instead, plant the orchid in a combination of fir bark chips and sphagnum or peat moss. Be careful not to add too much of the moss, as it can compact and restrict circulation as well. Consider five parts bark to one part moss. The addition of the moss will help the medium retain some moisture, yet keep the roots from rotting. Soak the fir bark before potting the orchid. This will help make the moisture available to the roots of the plant. Using dry fir bark can repel water and keep the moisture away from the roots. As in the case of cacti soil, perlite is a useful medium to add, as it aids in aeration and holds moisture for the roots of the orchid. Fir bark can eventually break down and become soil, so orchids need to be re-potted every one to two years or after every flowering.