Possible Vanilla Orchid Root Rot
 

I recently started growing vanilla orchid cuttings. Today I noticed their stems are turning brown/black. A quick google search makes me think this might be root rot.

What could it be and how could I save them? :(

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Gera,

A stem should never be black, so you're right that there's something wrong. I would feel the base of the stem to see if it is still firm or if it has become mushy. If it's mushy or if the black part is spreading I would say that part of the stem can't be saved. In this case I would cut above the dead tissue, into some healthy tissue, and replant into some fresh sphagnum moss to try to reroot the cuttings.

Ghuylar,

Thank you for your quick reply. The stem is still firm but it looks like I’m going to have to cut and replant.

How do you avoid root rot?

Definite signs of rotting there.

That rotting or rotted portion will likely be out of action now. You might need to remove that section (plus a tiny tad bit extra), and then repot ----- into new media. But don't allow the media to get overly wet. Lightly damp ---- lighty moist. Avoid relatively long periods wet or soggy media.

There's always exceptions where some plants can handle wet and soggy etc. But ----- for now, try less wet. That's if it was quite wet, and was remaining quite wet.

Also - gentle air movement is often beneficial - for humid regions.

Should I repot it immediately after cutting the affected part? Or should I try to root it first?

Gera ----- just try repotting after you cut. Keep the sphagnum just lightly damp. Also ---- if possible ---- pack the sphagnum relatively firmly ----- don't make it all loose etc. Firmly packed sphagnum is known to behave a bit differently in the way it distributes water or moisture around ------ a more beneficial behaviour that is.

Another thing you could do is ----- once the firmly packed sphagnum is lightly damp only, use a little spray nozzle to spray water toward the sides (rim) of pot. The water is still going to get spread, but at least it starts most wet at the sides before spreading around.

You may also want to consider just laying the cutting on the moss. These will only produce roots from the nodes so unless there’s a node near the cut end burying that end probably won’t really help the plant root. I think you’re better off leaving the cut dry and placing the cutting so that the aerial root has the opportunity to grow into the substrate on its own.

You may also want to consider alternate substrates. I have mine in a fast draining peat moss based mix for terrestrial orchids in a clay pot. South Park has theirs in scoria. I think both these media are going to dry faster than moss which may prove advantageous when trying to avoid rots.

That method that alice mentioned about laying the orchid cutting on top of the moss sounds good.