A Practical Guide to Soil Mixes for Different Houseplant Types
Generic potting soil doesn't work for every plant. Here's how to choose or build the right mix for succulents, aroids, ferns, and orchids.
Published · Updated · 6 min read
Photo: HandsInSoil by M Tullottes (Public domain)
Why one soil doesn't fit all
Soil mixes differ mainly in how much water they hold versus how much air reaches the roots. A mix built for a moisture-loving fern will stay far too wet for a cactus, and a fast-draining succulent mix will leave a moisture-loving calathea chronically thirsty. Matching the mix to the plant matters more than the brand on the bag.
Succulents and cacti
These need a fast-draining, gritty mix — roughly equal parts standard potting soil, coarse sand, and perlite or pumice. The goal is a mix that lets water pass through quickly rather than pooling around water-storing roots that rot easily if kept damp.
Tropical foliage plants (pothos, philodendron, monstera)
A standard, well-aerated potting mix works for most aroids, often improved with a handful of perlite or orchid bark mixed in to prevent compaction and keep oxygen reaching the roots between waterings.
Ferns and calatheas
These moisture-loving plants do best in a mix that retains water without becoming waterlogged — standard potting soil amended with coconut coir or peat moss holds consistent moisture while still draining excess water.
Orchids
Most houseplant orchids are epiphytes that grow on trees in the wild, with roots adapted to open air rather than dense soil. Regular potting soil suffocates orchid roots; use a chunky bark-based orchid mix instead, which lets air circulate freely around the roots.
Signs your soil mix is wrong for the plant
Soil that stays wet for over a week after watering suggests too little drainage for that species. Soil that dries out within a day or two, leaving the plant wilting between waterings, suggests too little water retention. Both problems are usually easier to fix with a soil change than by fighting the mix with a different watering schedule.