10 degree minimum

[SouthPark]

Originally Posted by Fredmax

I had always assumed anything below 15c regularly (over 12 weeks) was terminal as the equatorial species rarely get below that natively.

Fred - I have read that some plants require temperature to be in certain ranges for carrying out certain functions - biological and/or chemical stuff needed for cell development, and food making, energy or whatever important processes there are for the orchid to grow or stay healthy.

Eg. if the temperature stays relatively cold for weeks, or is on average relatively cold for weeks, then some orchids that require say tropical conditions and temperature might not be able to handle it.

Also, if some plants require temperature at certain times of the day to be roughly 'above' a certain value for supporting some important processes, and to later be below that temperature for something else (eg. resting) ----- then some plants could have issues if the conditions aren't 'provided'.

Also - there are details found about temperature change and rate of change. If temperature changes from one temperature to another relatively quickly, and if the initial and final temperature difference is large ...... then cells can develop problems, like dying. Sometimes, warm leaves getting chilled very quickly somehow (or the reverse) ...... can get bruising or cell collapse. This can also be 'promoted' by abruptly putting cold water on warm leaves. Or spraying alcohol on warm leaves - where cooling effect chills the leaves (under some conditions) ----- could probably cause some health issues.

And in a green-house, if it's humid and moist, and if there's no air-movement to suppress or eliminate certain unwanted fungal/bacterial activity (eg. by moving air over leaves and stem, and over roots and through potting media), then issues can occur that way.

So various considerations should be made about the growing area and environment and the growing/watering/fertilising/mag-cal/potting/potting-media etc methods.

Once these aspects are listed ----- then we have to look at each one, to see if issues could exist. And if one or some exists ------ need to see if we can do something to address it, to remove the issue(s).

I'm not a collector of a huge number of orchids, but have enough tropical type orchids grown for relatively long periods of time - a few decades. And a few decades ago, I wasn't able to keep alive 4 orchids. I initially thought it was 3, but actually 4 - and can even remember them. An L. anceps. C. bowringiana, Blc. Memoria Crispin Rosales, C. skinneri. They were the first lot of orchids that I grew. They didn't make it because I was a newbie and didn't know how to care for them.

But - interestingly - thereafter, I've never had any orchid die in my care. This has been due to - in a large part the fantastic tropical growing conditions here (temperature, air-movement in my growing area, lighting levels etc) ----- and surprisingly not much 'pest' activity in my growing areas. Or if there is ---- there hadn't been much or any nasty pest activity that I had to really deal with, except spider mites on paphs and catasetum.

The other aspects behind the health of the orchids is what was described before - making sure to avoid doing things to the orchid (or parts of orchids) that can lead to a down-turn in their health. So basically - lots of reading about what can cause orchid health issues, and how to cut down or eliminate issues.

It's true that there are always uncertainties --- things sometimes beyond our control -- like encountering virus (which I've never had issues or seen the results of - due to luck most likely), or just something.

I did have something concerning happening to my entire batch of catasetum last year, where the whole lot of them began to have sections of their leaves rot in sections in or around the 'crown' region. Something basically got on the whole lot of those catasetum type plants --- 20 or more of them. Application of a fungicide/bactericide sorted out that situation. That was concerning actually, but panned out well in the end.

I think it all came along after a spider-mite attack. Possibly soap spray solution got the leaves wet for too long (within the crown region) and some nasties just started to destroy the leaves around the crown region - rotting. Interestingly, the treatment was massively effective (with yates anti-rot phosacid) - which just so-happened to work. Amazing turn-around on every one of the catasetum-type plants.

I did have issues once with two juvenile paphs, with leaves unexpectedly getting rust coloured spot (small to begin with - on old and new leaves!), which spread - leading to rot. And also very interestingly - copper spray sorted it out amazingly - when other stuff (thiomyl, yates anti-rot appeared to be ineffective).

The leaves had not even been wet! So this is what I mean about some uncertainty.

But having some goodies on-hand if we need it --- treatments --- can be handy for sure.

I did recently see for the first time, a dendrobium beetle larva attacking one of my mini-catts! Possibly brought about by cymbidiums nearby with the long lasting flowers - may have attracted up those beetles.

So watching the orchids like a hawk each day can definitely help cut down on certain problems, or gives time for us to respond to situations.