Catasetum temperature in dormancy
 

What is the ideal minimum temperature for catasetums in their dormancy?

I've been keeping my dormant catasetums outside for winter (this is my first won't with them) and on average it gets to about 10C (50F) at night. The temperatures this week will do to 6C at its lowest. Is this ok fort them? Or should I be keeping them indoors through winter?

Also I have a couple catasetums seedlings still in growth.. should I still be watering them?! (I have still been but not as often)

Keeping them bone dry in winter helps prevent problems in cold temps. I bet 6C should be fine with dry roots.

Yes, keep watering/fertilizing them until they stop growing.

This is still pretty early winter in Australia. I think that you should consider bringing those dormant Catasetinae inside. They will put up with 10 deg C, but lower is pushing it. Since they don't have leaves, they don't need any care (and don't really care about light, they're sleeping) so they won't take up a lot of room in the house.

For the ones that are still growing, it is getting to be time to push them into dormancy if they aren't going already. By the end of the month, stop watering. You do want them to get their "beauty sleep" so that they are ready to grow in the spring. These also need to come into the house or similar warmer area if they aren't there already.

Have brought the little guys inside now. Stuck them on the bottom shelf of my book case so a) I'm not tempted to water them and b) they might get a bit less light to encourage dormancy.
Meanwhile I discovered a little surprise nubbin on my tenebrosa which had only been dormant for a couple weeks!

Tenebrosum is usually the first to wake up.

It's really, really tempting to start watering. No, no, no! You need to wait until the new roots are around 6-8 cm or so (Usually there is a first group of new roots, and then a second group... wait until the second group is well developed before even thinking of watering) By that time the leaves will have started to spread out, and only then do you resume watering. So you have at least two months, maybe three before it's ready to begin watering again.

At this point, light is not particularly important. Once you see leaves you will want to increase the light. But that's not going to happen for awhile.

Here is an excellent culture summary from Sunset Valley Orchids, one of the top nurseries for this group. It's written for the northern hemisphere, but just add 6 months to all the "month" references.
Sunset Valley Orchids - Catasetinae culture

Thanks Roberta! I may need to put some red tape around this shelf 😳

Another question for the group - attached are pics of a Fdk After Dark variety. I was sure this growth was a flower spike as the plant is still going into dormancy. BUT... It has roots!!! Can flower spikes have roots?? I'm so confused!!

Question... did you get this plant from a local grower who had actually grown it (not just acquired it)? Or was it a "recent arrival"? If someone local has actually grown it for a couple of years, it has had its seasons adjusted. If it is a recent import, the plant may be confused and need some work to get it on the right schedule. You can do that by pushing the plant into dormancy by stopping water. It may then not want to wake up in the spring... which is OK. I have had the experience of acquiring a member of this group from a southern hemisphere grower, and have the plant stay dormant for a full summer season through the following winter. The next spring it was fine. So just observe the plant - it will do what it will do, but give it the correct "treatment" for the season and it will do fine.

Roberta, excellent point to highlight. I saw this first Hand with a couple of catasetum plants from a South America vendor/ At first did not give it much thought, but then it made sense that plants were acclimated to southern hemishpere seasons and had to sleep through a full year before they adjusted and woke up. The plants were purchased in Florida in May (redlands show) and had just come from South America as they approach their winter, they continued to sleep through our summer and winter and woke up all normal at the next spring. Vendors should have said something. guess they did not want to discourage any sales. Plants skipped a whole year of growing.

I got the plant off eBay about 6 weeks ago. But it came with the little nubbin already present actually, and all its leaves still present. I got it from a seller in Queensland (same state as me) so shouldn't be a huge environment difference. But yes... Youre right, either way I'll have to Keep it dry.
Will let you know if it's a flower spike though!! Apparently it is possible for them to produce roots...