If anyone can help me diagnose the problem (so I don't do it again!) and save our cactus, I would be very grateful. My husband purchased this cactus from an outdoor nursery in Tucson, AZ about 4 years ago. He moved it from a dry climate to a more humid one, but the cactus has always lived indoors and has appeared healthy - green, growing, etc. A year and half ago I replanted it in special cactus soil and a larger pot. In it's current location (close to a window, but also a heat vent), where it has been for the past 1.5 years, the main stem has grown by at least a third, and the smaller stem has grown completely - signs to me that it was doing well. I water monthly, and add fertilizer maybe three times a year. During winter, our thermostat is always set at 64 degrees or higher. I have worried about the cold coming from the window during the winter, but hoped the heat vent would mitigate the chill. As we do every year (or every time we travel, which is fairly often) for Christmas, we left for a week and a half, during which time the blinds were closed and the heat turned down to 60 degrees. I watered before we left as well. This has never been a problem in the past, but last Saturday when we returned home, we found our poor cactus in this sad state. The smaller stem was flopped over and resting on the ground (I propped it up with dental floss), and blackness and mushyness were plentiful. I assume it was the combination of cold, water, lack of sunlight that hurt it, but this has never before been a problem, and our other cactus (different kind, no heat vent nearby) looks normal. Is our little guy a goner? Should I take the last green portion from the tip of the smaller stem as a cutting and toss the rest? Please help me if you can! Thanks
Welcome to the Forum, KS. Sadly, I think that your assumption in re. cold/damp/dark conditions is correct...gosh, sure doesn't look good, does it? I feel for you: hard to lose a plant you've known for a long time. Am sure that our cacti-savvy members will weigh in with advice (Hey, mandarin...!) as to any possibility of first aid and/or preserving the new growth. Good Luck!
That is some kind of Cereus, and they usually can stand temperatures down to freezing, in dry conditions. Possible reasons for its death: 1. Wet, dense soil + too cold for too long time. 2. If it had not been watered for some time the fine root tips had most likely died, and they must be regrown before the plant can take up water, which makes things worse. Most collectors give their plants a rest in winter and when we start watering again in spring we do it very carefully, otherwise the plants are likely to rot. I had something similar to yours once, it stood in an small, unheated window in winter, no water about 6 months. I did pretty well. Most of the plant cannot be saved, but the upper parts can be rerooted if the cut surface doesn't show any discoloration. Let the cutting(s) dry for a month before trying to root them (there are numerous descriptions of the procedure on the Internet). Dusting the cuts with cinnamon or sulphur powder is a good idea. The new growth looks etioliated however, I would not bother trying to save it unless it had a special meaning to me. I think your soil is too rich in organic material. This is a very common fault with commercial so-called cactus soil.
it's been extremely cold AND windy this year (which makes it even colder)...the wind coming through the window as well as keeping the wall cooler than usual and that the bit of watering you did before you went on your trip is the culprit here. the temps were much colder than expected and the growing medium was wet on top of it... truly a shame as that is/was one heekofa beautiful plant!!! i agree with mandarin about the soil not helping the situation any...i use mostly small gravel as the growing medium for this type of cacti - small gravel with a bit of commercial 'cactus soil' and also a bit of sand, too. i also agree about not watering most cacti - especially large specimens - in winter. they really just don't need it. further agree with cutting off whatever is still green and viable! allow to dry/callous for at LEAST a month before potting up. i'd also hold on to the original plant as well - if the discolored portions are not mushy, then it may just recover now that you're home and will have the heat up to what it is accustomed to at this time of year. it's a pretty off chance, still, well worth it to hang on for a bit - just in case. i would leave the plant were it is and let it sit completely dry until spring. you may see new growth once you start giving it some water then. i would take the cuttings now, though, even if you're going to keep the main plant to see if it recovers. put cinnamon or sulpher on the cut ends - both on the main part as well as the bottoms of what you're going to root. good luck!!
Oh thank you all for the advice!! I REALLY appreciate it. It makes me feel better to know where I went wrong, and will help future generations of cacti. Also thanks for identifying it, mandarin. Since there is so much knowledge out there, can I ask another question about my OTHER prickly friend? I have had this one also for about 4 years - it came home from AZ with my aunt as a house warming present. I repotted it then - same special cactus soil that I now understand I'll have to add some sand and gravel to - to try to eliminate a dangerous tilt. It has been receiving direct sunlight from a large window, monthly waterings, and has generally been in the same conditions as the above. The first half of it's life with me saw no fertilizing, but now I'm fertilizing sparingly. Here's my question: I can see almost no sign of growth, save for the very slow healing of a very deep crack (#2 photo) in the right-most stem that happened during transit 4 years ago. Is it healthy? Am I depriving it of some vital element? Should I even expect to see growth or flowering? Also, this grayish border around what looks to be previous injury (#3 photo) - is it normal/okay? Thanks again!
The plant looks fine. I don't understand why it has not grown, but I once read that some cacti can do that when they are not happy with the growing conditions. Try repotting it in a much more open soil and place it outside in summer, if you can. There are other factors than the light level that make cacti thrive, temperature variation between day and night is one of them. About the soil: I have not grown a cactus like that in a long time, but the last time I used a soil made of 10-20 % organic matter, and today I use even less. About 50-70 % of my soils is coarse material that provides drainage. Just to give you an idea.
some cacti are just extremely slow growing. some need ample room for the roots so that they can grow properly. this one looks under potted and i would move it to something larger as well as use a better growing medium. i can't tender an id for it - maybe mandarin can? definitely no more than 20% organic matter - i use 10% to 15% depending on particular species. and i do research to find out where the plant is native to and what the soil conditions are there and then pot accordingly. the gravel i use is from an aquarium store. completely natural stone - definitely has no color added to it. i have two types - one is very small bits/pieces and some very small pebbles and is completely unpolished and the second is larger pebbles and is a bit polished (although, i think it's naturally occuring from when the stones were out in nature, rather than being put through a machine, as there is some unevenness to it). some cacti do well in lava rocks, too. what you have will do fine in the basic small stones i'm describing, though. the sand is purchased in the garden dept of one of the big box stores (home depot or lowes).
