The top of my Trichocereus spachiana stems have started to rot again, so I've cut them off. I don't know why this keeps happening. I've dusted the cut ends with flowers of Sulphur, to stop any mold forming There was a shoot growing from a previously cut bit and I've tried saving it. I've put it on a saucer to dry the cut end and I hope to plant it later. My tall Cleistocactus has lost some height too. Does someone have any ideas as to why this happens ?
Seems unusual for the top to rot, often the rot comes up from the bottom. Although I guess the top is the softer part and probably the most succulent. I often find that during the winter when we get a sudden warming of temperature after a cold spell condensation forms on the plants and they can actually run with water. That looks very similar to a stenocereus that I have and after losing one some years ago I now give it extra warmth in the conservatory rather than the greenhouse.
Thank you, although my greenhouse is sheltered and has a wall on two sides, I'll be bringing it into the house in future winters.
Even the dryer atmosphere in the house would make a difference. I don't know about you @Michael Hewett , but with our very wet autumn's, these days, trying to keep the humidity down is almost impossible.
Yes, my greenhouse gets very damp, and although I ventilate it regularly by opening the door and windows, the air still feels damp in there when we get a rainy period.
