The most important question about cacti growing: Watering
The quantity and frequency of watering is one of the biggest questions to cactus owners. Cactus does not wilt when it already needs water, so the plant gives few hints that thirsty. The good rule is to water when the top 2 to 3 centimeters of soil is dry. But you should take into account the season.
Plants require more water during the period of summertime growth than they will need during the slowed period in winter. In winter they can be watered only once a month. During winter, you should only supply just enough moisture so that the roots do not dry or dye. One of the most important points about cactus watering is to never let the containers stand in water.
Waterlogged soil quickly causes rotting of the roots with fatal consequences for the entire plant. Cacti do need to be watered and fertilized, but not as often as any other plants. Water the containers when they dry out and check whether the soil dries thoroughly between watering. Do not water during rainy periods, in winter or right after repotting. Many varieties have dormant periods and watering is very harmful. Consider also that small containers require more frequent watering than large ones.