I'm terrible at telling when it's dry until it's totally parched. I'm new to this and really wanna keep the poor little guy alive. Is there a safe interval I can just set a reminder for? It's a small pot, like I can hold it in one hand.
Someone just gave me a "moon cactus" (i.e. https://en.wikipedia.org/wiki/Gymnocalycium_mihanovichii grafted onto something else) and that just eventually died on me. Never figured out whether I watered it too little or too much.
Edit: I totally misinformed you. Please disregard the below!
Those are usually grafted onto a euphorbia species, which like a little more water than cacti do. There are always so many variables though! Soil, ambient humidity, hours and intensity of light... I tend to err on the underwatering side just to be safe.
Gymnos and other cacti can only be grafted to other cacti, never a euphorbia. Often the rootstock used for grafting cacti is the Selenicereus "dragon fruit" cactus. This is because it has a faster metabolism and can make the scion cacti grow faster than normal.