This post might be a little premature, but even if we're not quite at the endpoint yet, enough has happened that I think a post can be built around it. So here we go.
I decided a while ago that I wanted to propagate some of my Selenicereus chrysocardium cuttings, both as insurance against a potential Selenicereus disaster and also to have on hand to trade or sell, should the situation arise. I wasn't sure quite how to do this, so I . . . basically just guessed.
The first step was to decide how many cuttings to take, and of what size. When we'd done this at work, we just cut the ends off of some long "fronds" (actually stems) and stuck them in soil. Which worked. I couldn't really do that, because my plant is only just so large, and and I didn't want to hack it to pieces just for propagation. So what I did was, I tried to make multiple cuttings from a single stem, which I did like so: I cut the -- I guess you'd call it the "midrib?" -- in multiple places, dividing the stem into multiple pieces which all contain some of the midrib.1 The pink lines in the below photo illustrate where I cut.
I planted them in vermiculite, in a plastic salad-mix container. Why vermiculite? Well, I was concerned about fungal problems if I planted in potting mix, and vermiculite is a sterile medium. It also tends to be really good for rooting things, even things that are ordinarily difficult. This may not have been completely necessary either: like I said, when we did this at work, we just used soil directly and it all turned out fine. But I wanted to be careful. Thus:
Very little has happened since then. I initially left the top of the container off, for fear of fungal problems. After it'd dried out a few times because I forgot to water it,2 I tried putting the top on. This turned out to be a bad idea; the next time I opened it up to check, I had botrytis growing on the cut ends.
Botrytis, sometimes also called gray mold, is a grayish fungus that attacks many, many types of houseplants, and I saw it all the time in the greenhouse at work, usually on leaves that had died and fallen on top of wet soil. It's unusual in a home environment because it's unusual for a home to be humid enough to keep an infection going. I removed the cover from the plastic container, sprayed the cuttings with neem oil, and haven't seen any Botrytis since.
I'm a little impatient for something visible to happen -- it seems like I should have at least one of these producing new foliage by now -- but I know they're doing something, because they don't pull out of the vermiculite easily like they used to, so there must be roots in there, and I've actually seen one root so far:
So it should only be a matter of time before I get foliage. And then I can pot them into separate pots, and they will thrive and grow and life will be perfect forever. Or that's my plan, anyway.
1 This may not be necessary, strictly speaking; I am unsure whether one can propagate from pieces which don't contain the "midrib," never having tried it. I think they did try it at work after I left, but I don't know how that turned out. So I was basically hedging my bets here -- I know that you can at least do it the way I'm describing, and if it turns out that a person can also propagate from smaller pieces of the plant, then that's great. Let me know if you know.
2 Wet vermiculite looks exactly the same as dry vermiculite, so I can't just look at the plants and know whether they need water. Which means that sometimes they dry out. Fortunately, Selenicereus chrysocardium handles drying out quite well, so long as it's for a reasonable amount of time.