Potting Mix

Ordinary garden soil compacts badly in a pot, draining poorly and starving roots of oxygen once it settles. Potting mix is formulated specifically to avoid that: a blend of lightweight, well-draining materials such as peat or coconut coir for water retention, perlite or pumice for drainage and aeration, and compost or aged bark for nutrients.

Different mixes suit different plants: succulents and cacti need a fast-draining, mostly mineral mix with little organic matter, while tropical foliage plants generally want a mix that holds more moisture between waterings. Using the wrong mix, particularly one that holds too much water for a plant's needs, is a common cause of root rot in containers.

In a hot climate, potting mix also breaks down and compacts faster than in cooler regions, since higher temperatures accelerate the decomposition of its organic components, which is part of why repotting into fresh mix every couple of years, not just moving to a bigger pot, matters for long-term container plant health.