I was recently gifted a moon cactus. I repotted into dry cactus/succulent mix because it was in a tiny plastic pot with wet soil that wasn't draining. Here I am a week later and a slight discoloration on Friday is now large black spots which I believe to be fungus caused by it's previous overwatering.

I really want to save the moon cactus. Where can I find good rootstock to do an emergency graft onto? I've tried googling and I guess I'm looking in all the wrong places... Thank you!


Btw I am a cactus noobie so any information would help

Most "Moon Cactus" use a Hylocereus as the recipient plant. Hylocereus is Dragon Fruit. But grafting isn't as easy as you might think. You say you are a cactus noobie but have you done any grafting?

Before you do anything else, though, did you water after you repotted into a larger pot? Did you take all the old soil off before repotting? How big is the larger pot? Is the soil very damp a week later? Are those dark spots squishy? Dry feeling? Can you rub them off with your finger?

More photos of the pot and soil would be helpful.

I did not water the cactus after repotting it (it's soil was very damp and was not drying out so I thought it might like dry soil for a week or so)

I took off as much of the old soil as I could without ripping the roots. I didn't think it was the correct soil (I bought it from a big box store). I put it in a cactus/succulent/ palm blend from miracle grow that had no water added to it and felt dry to the touch.

The pot is too large but it was the smallest my particular store had that was made of porous clay (6"diameter)

The soil is very dry that I moved it into. I hadn't gotten to water it yet.

The dark spot is squishy and I cannot rub it off. It moves under the outer "skin" of the cactus and seems to be progressing pretty fast

I have absolutely no experience whatsoever with grafting. I just went to it as a last ditch effort to save Sir Reginald (I named the stupid cactus). I have watched a dozen YouTube videos and lurked on a few forums today to try and learn and figured I'd try with one of the pups to see if a piece of Reggie could be spared. I know he can't grow on his own due to his lack of chlorophyll (I just learned this through Google)














I added the rocks in after because Reggie wasn't very stable and I didn't want him to take a tumble

Thank you for responding!

If I do graft I'd prefer to not do it on a tropical cactus again but I don't know what other species of rootstock I should consider

Also,it looks like the pictures being uploaded aren't the best quality... I'm not sure how to upload higher quality pictures

Pictures for texture reference

Black means necrotic (dead). It concerns me that you said it is spreading.

Try this: take a sharp exacto knife (or other small sharp knife) and cut the squishy spot out of the cactus body. After every cut, clean your knife with rubbing alcohol. Start with a small divot but keep cutting until there is no more squishy and the tissue is green (no brown).

Lightly dust the cut spot with cinnimon. Put your plant someplace with no direct sun but where there is good air circulation.

Let me stress and re-stress: DO NOT contaminate healthy tissue with poor cleaning of your knife.

Alright, I did it. I cut into Sir Reginald :(

Did I do this right?















I didn't get any soil in the cut and I wiped between every cut (evidence by how much gauze I used). Do I plant him again? Should I leave him out of the soil and let his roots air out?

Excellent!

The use of using Hylocereus as the recipient plant is wrong. This is a tropical cactus which requires more water than regular cactus. Also mixing with other plants with different requirements is leading to trouble. Using almost any column types would be more of a close match. I don't know why they don't use other stock when I see them for sale. I guess Hylocereus is cheap and easy to grow. I have lots of it growing after the top rots off. I cut and throw away excess growth.

I have a little Gymno grafted to a Hylo that has been pretty happy for several years now. The reason this plant has lasted so long is that the Gymno is a dark enough red that it has some chlorophyll to help support itself. I water it just like my other Gymnos that are not grafted. The bottom half is Hylocereus undatus and is always used because it is very adaptable to dry-wet soils. The top is Gymnocalycium mihanovichii var. friedrichii 'Hibotan', a natural mutation.

Most "Moon Cactus" die within a year or so because the Gymno is not helping support the cactus as a whole unit and, eventually, the Hylo can't support both parts by itself so it just gives out. The problem is that the Hylo growth point is cut off and replaced by a plant that can't add anything to the relationship. If your Hylo grew branches while supporting the Gymno, it wouldn't die.

Sorry P-P, your plant is doomed even if you save it.

I agree with Stush, though, the mixed pot will be tough to maintain. The Moon Cactus will adapt but the little cactus and the succulent can't tolerate the conditions the other needs.

Daisy is correct, I think the lifespan of the man made tops at most, is 2 years.

As long as I can get 2 years out of it instead of a week I'll call it good.

I'm still looking to try and graft some of the pups. I'm going to the store this weekend to find some suitable bases to try and graft onto.

If the original Reginald dies at least I can keep his lineage going (maybe on something with better growth on bottom?)

Do you know anyone with a dragon fruit tree?

I have several rooted large stems that I don't want. For postage I can send. Priority Mail is about $8 to $12 but if under 13 oz. First Class is about $4. These stems have a lot of water and 13 oz. is very few. Message me for your address.