Editing Cactus (section)

===Growing medium===
[[File:DarjeelingCactus.JPG|thumb|Cacti in a greenhouse in [[Darjeeling]], India ]]
The purpose of the growing medium is  to provide support and to store water, oxygen and dissolved minerals to feed the plant.{{sfnp|ps=none|Brown|2001|p=87}} In the case of cacti, there is general agreement that an open medium with a high air content is important. When cacti are grown in containers, recommendations as to how this should be achieved vary greatly; Miles Anderson says that if asked to describe a perfect growing medium, "ten growers would give 20 different answers".{{sfnp|ps=none|Anderson|1999|p=217}} Roger Brown suggests a mixture of two parts commercial soilless [[growing medium]], one part [[hydroponic]] clay and one part coarse [[pumice]] or [[perlite]], with the addition of soil from earthworm castings.{{sfnp|ps=none|Brown|2001|p=87}} The general recommendation of 25–75% organic-based material, the rest being inorganic such as pumice, perlite or grit, is supported by other sources.{{sfnp|ps=none|Anderson|1999|p=217}}{{sfnp|ps=none|Hewitt|1993|p=147}}{{sfnp|ps=none|Innes|1995|p=23}}{{sfnp|ps=none|Keen|1990|pp=27–28}} However, the use of organic material is rejected altogether by others; Hecht says that cacti (other than epiphytes) "want soil that is low in or free of [[humus]]", and recommends coarse sand as the basis of a growing medium.{{sfnp|ps=none|Hecht|1994|p=140}}