Wait until the earth is dry. To check, scratch and feel with your fingers well below the surface of the soil. Immerse the plant pot in a container with water, for 1/5 of its height for 3 minutes.
Origin
Central and south America, Africa (Madagascar, Ethiopia, etc.,), Asia
History
It was probably introduced from America in the "Old world" thanks to the migratory birds, and is the only cactus spontaneous outside of the united states.