Grafting, which can be done with many plants, is a propagation technique in which a gardener will take two separate plant species, cut them and grow them together as one plant. The plants, if they are compatible, will bond and grow as one. Moon cactus is one of the most popular grafted cactus that gardeners keep.
The top cactus of the moon cactus has a mutation that causes it to lack the chlorophyll that makes it green. This mutation exposes the red, orange or yellow color beneath. Cactus that lack chlorophyll cannot live on their own – they die as seedlings unless grafted onto another cactus with chlorophyll. The two species most commonly used for moon cactus are Gymnocalycium mihanovichii as the top cactus and Hylocereus spp. as the base.
If you can find a healthy specimen of Gymnocalycium mihanovichii that lacks chlorophyll and a healthy Hylocereus, you may want to give it a try. Follow the seven steps below to grafting cactus, and check out this video University of Nevada Cooperative Extension's ML Robinson demonstrates how to graft cactus.
1. Purchase a healthy red, yellow or orange Gymnocalycium mihanovichii and a healthy Hylocereus large enough for grafting.
2. Disinfect a sharp knife (to reduce risk of infection).
3. With the knife, cut the top off of a healthy Hylocereus cactus. Cut a piece that is the same size of the G. mihanovichii that will be grafted onto it.
4. Trim the edges of the Hylocereus so that its edges slope downward.
5. Cut off another thin layer from the top of the Hylocereus and cut a thin layer off of the bottom of the the G. mihanovichii. Place the two cacti together so that the rings of their vascular bundles directly face one another. The vascular bundle is that small round ring in the center of a cactus’s cross-section. The vascular bundle is visible in the photo on the right.
6. Hold the two cacti together with rubber bands (don’t make the rubber bands too tight or too loose).
7. Wait two to three weeks for the two plants to grow together, and then gently remove the rubber bands.
You can always purchase an already grafted moon cactus from your local garden shop, as it is a quite popular grafted cactus. There are other cacti that you can grow together as one. Just research the two cactus species you’d like to graft, and give it a try! Good luck!