Sorry, it's not possible to tell from the photo. It needs to be sharp and in focus, and preferably show a range of angles, including overall views and close ups of the stem and spines etc. It may possibly be an Opuntia relative.

50deg will be plenty warm enough - I think they would be totally happy with just frost free, so 40 deg would work fine. They may grow a bit at warmer temps, and get a bit leggy, it depends how much light they get.

Thanks for the mite confirmation. I don't think the nodules are round enough to be Rebutia. Does the flower help in id? https://i.ibb.co/cYFhzsw/Mammillaria.jpg It's a bit etiolated, so shoots are a bit cylindrical. Some Rebutias have cylindrical shoots anyway. The flower confirms it's a Rebutia. I...

When touching the hair of your specimens, does it feels coarse /stiff or soft? I have a little ‘Old man’ myself and I am trying to figure out which genus it belongs to. Judging by the photos I have studied , Cephalocereus hairs seems to resemble nylon rather than the more cottony look of Espostoa’s...

Aiko wrote: ↑Mon Nov 09, 2020 8:26 pmTo me this was a clear example of abusing (yes, I call it that) the identification system and why the rules where set up in the first place.

I can’t see how the rules were broken Aiko, let alone abused.

I'd like to complain about the lastest moderated posts last night (8th Nov) asking for succulent id! I think the moderation was too heavy handed, and to be blunt, rude. I'd hope we try to be friendly and helpful here. A new poster has asked for 2 ids, 1 per thread. They correctly assessed that 1 was...

I think the first plants could be C. senilis.
The second pot is an Espostoa, for sure.

Evidently Cephalocereus senilis is now infrequently grown I remember it being a popular plant 40 years ago or so when I was first into cacti; less so now, it seems. It appears much less frequently as both plants and seeds on sales lists. Presumably Espostoa seed is widely available from field colle...

warm weather trigger a response...‘wake up’ I doubt it , short days, no water . Low 70s isn't that warm compared to where they normally live anyway. Its almost winter desert weather. night time temps dropping into the low 40’s this weather for early to mid November is predicted to continue. I don't...

You don't say where you are, and it's not given in your profile, so we don't know what winter is like for you. However, if you can provide light and warmth, sowing in the winter is good. Any of those species would be fine. If you have plenty of seeds of some of them, why not sow some seeds of the sp...

Tucson gets cold temperatures in winter. I wouldn't worry so long as the minimum is above freezing and average temperatures are well above freezing.
https://www.meteoblue.com/en/weather/hi ... ca_5318313

These cacti should be carefully watered just if their stems are in active growth. Temps you mentioned are rather winter ones for Mexico and other subtropics where these originate. Cacti of such a size will not dry out or die if kept dry for next 4 - 5 months. If your daytime temps are 65-70f I'd ex...

I am fairly certain that I have not overwatered it. Underwatering will cause older leaves on Aloes to dry up. Aloe aristata (and some hybrids of it - yours may be a hybrid) survives outdoors year round in the UK with little or no rain protection. If it's in very well-drained soil, it can take a lot...

Many succulents from southern Africa grow strongly in the spring and autumn - in fact some come from areas with dry summers and winter rainfall and are thus winter growers in habitat. Huernias don't want to be cold in damp in winter, but if it's mild and sunny they will enjoy a bit of water. Just ma...

Why not just buy a cactus seeds mixture from a standard flower seed supplier for a few dollars?