How long a cold spell do Chamaelobivia/Echinopsis need to initiate flowering?

[edds]

I have some Chamaelobivia and Echinopsis cacti that I have moved from my office (minimum 8oC and daily in the 20s) to my cold greenhouse around the end of January to give them a cold spell to try and trigger better flowering. I also have some Echinopsis still in my office that I was thinking about moving the the cold greenhouse to see if they might flower.

But how long a cold spell do they need to trigger flowering?

(I'm trying to work out how long before I move the Chamaelobivia back to the office to start them flowering and whether it is worth moving the Echinopsis or if I have missed that opportunity?)

[habanerocat]

Unfortunately I don't think you're going to get an answer to that question with any degree of certainty.

Again not the answer you're looking for but I would discourage moving plants around like that for fear of spreading bugs and problems with scorch.
My greenhouses badly need to be washed down, but I'm half afraid to do it for fear of scorch.

[edds]

Unfortunately I don't think you're going to get an answer to that question with any degree of certainty.

Thought that might possibly be the case but was hoping some people might have some anecdotal information from their own experiences, maybe members from warmer climes who have shorter and warmer 'cold' spells but still get good flowering from these types of cacti?

It I thought someone might have read some research on this that might have been relevant.

If not it will be a good chance for me to experiment and report back!

Again not the answer you're looking for but I would discourage moving plants around like that for fear of spreading bugs and problems with scorch.

My collection is very fluid between the two 'sites' and always has been so my bugs are always squarely shared between the two!
(And unfortunately mealybugs, RSM and thrips are infecting plants at both sites which I am going to post about to try and find the best way to deal with with the limited palette of treatments we now have to work with!)

[el48tel]

I think there is another dimension to this.
Plants in habitat deal with local conditions. They get cold or they don't .... according to the weather. They flower .... or they don't.
Plants in cultivation get the conditions we impose on them. We can TRY to simulate the natural conditions. We might be lucky ... or we might not. But in the UK simulating 3000m above sea-level is a tad difficult ..... AND many of us hybrid growers are growing plants which don't exist in nature.

[SimonT]

I had a few Aylostera plants at work and they had a few flowers each year, but not that many.
Anyway, during Covid these plants started to produce lots of flowers in Spring.
I realised this was probably because during the lockdown the building was on shutdown and so the plants
were getting some cold nights for the first time! I took these plants home after that and gave them a proper winter rest- they
flowered well after that.

So I've been wondering as well about how much of a cold treatment is really needed, but for a different genus. I was going to try some experiments with seedlings but I've also been worried about spreading pests. I have several small spaces I grow plants and actually I've only ever seen pests in one of them. But there might be other ways of working this out?

[edds]

I've got three large Aylostera in my office as well. One flowers fairly reliably each year (A.'Celebration') but the other two (A.'Apricot Ice' and A.muscula) don't and I think need a colder winter so the variation in this even within a genus will be huge.
The pendant Hildewintera I have in the office seem to flower without needing a significant cold spell. However I have two upright ones that haven't flowered yet and may need colder conditions.

[esp]

This link refers to a paper, specifying 8 weeks at 5deg C:
https://herbalistics.com.au/determining ... eus-cacti/.
I haven't checked it out for any more details.

I guess an issue with a cold period is that it needs to be long enough to signify a seasonal change (and therefore anticipating the next seasonal change to Spring, with warmth, increased rainfall and pollinator availability), rather than just a spell of cooler than average weather, so several weeks seems reasonable.

A parallel, which may be relevant, is it's typically stated that Christmas cacti need 6-8 weeks of (say) 12 hours darkness to stimulate flowering - I guess mine typically start budding up in November, so in reasonable agreement with this, following the Autumn equinox.

[anttisepp]

Remember they have to be also dry until first buds will appear and don't turn the pots because it's also very important.

[habanerocat]

This link refers to a paper, specifying 8 weeks at 5deg C:
https://herbalistics.com.au/determining ... eus-cacti/.
I haven't checked it out for any more details.

That's a hard read.

Wouldn't a couple of small graphs have been great additions.

[edds]

Thanks for the paper - I can't find the full version online as it would have been nice to see the raw data and look at what sort of difference in flower quantity the different lengths of time produced. Interesting that the shorter times seemed to produce quicker flowering.