Moon cactus?

Question:does anyone know about the moon cactus? ive been looking all over the net for info, but i cant find any! i want to know care and history and general facts. i just got it.

Answers:
These are actually what are called a grafted cactus. That is, attaching one type of cactus to another to grow as one. This is actually done with a lot of different kinds of cactus for various reasons, but the one referred to as the "Moon Cactus" (just a catchy marketing name) is done as a novelty to keep the top, brightly colored one alive. It couldn't survive by itself because it doesn't have any chlorophyll - the stuff that makes plants green and makes food for them. These wild color variations are artificially induced by irradiation I believe. The top cactus is a desert cactus - Gymnocalycium mihanovichii. The bottom one is a jungle cactus, usually some type of Hylocereus. The bottom one has the chlorophyll and the roots to provide all the needs of the top plant. 98% of all of these colored novelty grafts are produced in Korea; they have the whole technique down to a fine science, and they produce millions of them. Put it in a location where it gets bright indirect light, or even in a window that gets a few hours of direct sun - preferably morning or late afternoon sun that isn't too harsh. Hotter sun closer to midday could burn the plant. Water the plant thoroughly, and don't water again until the pot is fairly dry about down to a depth of 1" in the soil. It will benefit from an occasional fertilizing with an all-purpose liquid houseplant food diluted to half strength. This can be done once a month in place of one of the waterings during its growing period - usually during late spring to late summer.