Common options include seed-starting mixes, all-purpose potting mixes, indoor potting blends, succulent and cacti mixes, raised-bed garden soil, and fast-draining cactus/palm/citrus blends.
Typical ingredients include perlite, horticultural sand, sphagnum peat moss, coconut coir, yucca extract, mycorrhizae, dolomitic limestone, aged bark, gypsum, plant food/fertilizer, and upcycled plant matter or wood fines.
Some mixes are formulated for fast drainage using perlite, sand, or aged bark. Others add moisture-control ingredients like yucca extract and coconut coir to retain water. Reviews note that while many mixes retain moisture well, some can hold too much moisture in self-watering setups.
Dolomitic limestone appears in several mixes to help balance pH, and gypsum is added to at least one raised-bed blend to improve water absorption.
Succulent and cactus mixes use fast-draining materials such as perlite, horticultural sand, and sometimes aged bark. They are formulated and marketed to prevent compaction and promote quick water flow.
