Editing Cactus (section)

===Propagation===
Cacti can be propagated by seed, [[Cutting (plant)|cuttings]] or [[grafting]]. Seed sown early in the year produces seedlings that benefit from a longer growing period.{{sfnp|ps=none|Innes|1995|p=28}} Seed is sown in a moist growing medium and then kept in a covered environment, until 7–10 days after germination, to avoid drying out.{{sfnp|ps=none|Brown|2001|p=92}} A very wet growing medium can cause both seeds and seedlings to rot.{{sfnp|ps=none|Innes|1995|p=27}} A temperature range of {{convert|18|–|30|C|F|0}} is suggested for germination; soil temperatures of around {{convert|22|C|F|0}} promote the best root growth. Low light levels are sufficient during germination, but afterwards semi-desert cacti need higher light levels to produce strong growth, although [[acclimatization]] is needed to conditions in a greenhouse, such as higher temperatures and strong sunlight.{{sfnp|ps=none|Brown|2001|p=92}}
[[File:PikiWiki Israel 14907 The Cactus Avenue.JPG|thumb|Grafted forms of ''[[Gymnocalycium mihanovichii]]'' grown in Israel]]
Reproduction by cuttings makes use of parts of a plant that can grow roots. Some cacti produce "pads" or "joints" that can be detached or cleanly cut off. Other cacti produce offsets that can be removed.{{sfnp|ps=none|Innes|1995|p=28}} Otherwise, stem cuttings can be made, ideally from relatively new growth. It is recommended that any cut surfaces be allowed to dry for a period of several days to several weeks until a [[Callus (cell biology)|callus]] forms over the cut surface. Rooting can then take place in an appropriate growing medium at a temperature of around {{convert|22|C|F|0}}.{{sfnp|ps=none|Innes|1995|p=28}}{{sfnp|ps=none|Brown|2001|p=92}}
[[File:Trichocereus bridgesii.jpg|thumb|''Trichocereus bridgesii monstrose'']]
Grafting is used for species difficult to grow well in cultivation or that cannot grow independently, such as some [[chlorophyll]]-free forms with white, yellow or red bodies, or some forms that show abnormal growth (e.g., [[Fasciation|cristate]] or {{linktext|monstrose}} forms). For the host plant (the [[stock (grafting)|stock]]), growers choose one that grows strongly in cultivation and is compatible with the plant to be propagated: the [[scion (grafting)|scion]]. The grower makes cuts on both stock and scion and joins the two, binding them together while they unite. Various kinds of graft are used—flat grafts, where both scion and stock are of similar diameters, and cleft grafts, where a smaller scion is inserted into a cleft made in the stock.{{sfnp|ps=none|Innes|1995|p=29}}

Commercially, huge numbers of cacti are produced annually. For example, in 2002 in Korea alone, 49 million plants were propagated, with a value of almost US$9&nbsp;million. Most of them (31 million plants) were propagated by grafting.<ref name=JeongChoLee2009/>