The importance of night time temp for cool growing orchids.

12 years ago

Last summer I kept my cold greenhouse below 75F day time high whenever possible and felt I did an adequate job. Since then I have learned that what's probably more important is to make sure the night time temp goes down sufficiently.

From successful cold growers in the San Francisco area I have learned that they allow the day temp to go as high as 80F but make sure the night temp drops to 50F or 55F. I'm going to do that this summer programming the swamp cooler to go on from 10PM to 6AM if the temp is above 55F. The 24 hour program has the swamper go on anytime the temp rises above 75F.

At the present time this becomes functional as the night time low is already as high as 63F. That's the lowest it went last night and things will only get warmer. Later on there will be nights with a low as high as 70F and higher. If the swamper is only set to go for temps above 75F this issue will not be addressed.

Nick

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Comments (4)

arthurm
12 years ago
Confusion, confusion. hot/warm/cold and cool growers. Nick, at least you have put some temps up for discussion.

Then we have terms like Tropical Lowland, Tropical Savanna, Montane and so on.

One typical cool grower is the Standard Cymbidium. A nursery guy around these parts would say that they are cold growers meaning that you do not have to keep them warm on winter's nights.

A range of 50F to 80F is impossible here and in many places without a lot of (expensive equipment) and i would refer to those orchids needing those sort of temps as montane or narrow temperature range orchids.
orchidnick
Original Author
12 years ago
We have a natural temperature range of below freezing to 100F plus. Many plants do just fine with this under shade cloth. Cymbidiums, AU Dendrobiums, Onc, Encyclias, most Cattleya hybrids and quite a few of the Catt specieas.

If one were satisfied with them life would be simple. Having extra energy and lots of time, mountains need to be climbed. The group of plants I'm tending to are the cloud forest plants of Central and South America. Specifically the entire Pleurothallis group and odd balls like Dendrobium cuthbersonii, Den subuliferum etc. Maxillarias, some Coelogyne etc.

If you want Draculas to bloom, right now I have about 10 of them doing just that, you need to jump through the hoops. One also has to be a passionate tinkerer, electrical systems, RO system, watering and automatic fertilizing systems, humidity controll etc. I get quite a kick out of dealing with all of that.

If you live in Pacifica, near San Francisco, close to the ocean, one only needs to open the window and every thing falls into place. But if you live in the near desert of Southern California then it becomes a challenge to create the environment of the Monte Verde rain forest of Costa Rica. And that is what gives me pleasure, so I do it.

You can have a goldfish bowl or you can maintain a salt water reef tank. Whatever turns you on.

Nick
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westoh Z6
12 years ago
Well put Nick.

Like others, I enjoy 'watching' you tinker.

Sadly, my temps are controlled by either the house or mother nature. In a few years when work isn't an issue, who knows? And you give me ideas!

BTW: I had always heard that the night temps were as or more important than the days temps for the cool growers??? Strange it was new for you as much as you tinker with this cool growing stuff.

Keep us updated on the how the night temps help...

Bob
orchidnick
Original Author
12 years ago
I finished the cool house in early 2010 so last summer was the first summer I faced. I thought I could get away with simply keeping a lid on the top day time temp. Things grew and bloomed, sort of. I can already see substantial improvements from all the changes that have been made. It's a work in progress.

While on the subject of temps, the other thing not to forget is to heat the thing in the winter. Even though they are cold loving plants, they will shut down and stop growing if the temp is allowed to get as low as 35F to 45F which it will in my area. Heaters need to keep a minimum of 50F to 55F.

Nick

The importance of night time temp for cool growing orchids.

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arthurm

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The importance of night time temp for cool growing orchids.

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arthurm

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