The charts on this webpage are created by
combining three great resources:
Temperature, light and water are very important
variables to consider when growing orchids.
Temperature, more so than water or light, is the
most challenging variable to try and control.
Ideally, rather than trying to manipulate
temperatures to suit your orchids, it's preferable
to select orchids that are well-suited to your
temperatures. The goal of this webpage is to
help provide a better understanding of the
temperature requirements of orchids by utilizing
charts that compare the average high and low
temperatures of an orchid grower's location to the
average high and low temperatures of an orchid's
native habitat.
Temperature equivalence is the primary concept
that explains why numerous epiphytic orchids from
Mexico, Australia, New Zealand, Brazil, the
Himalayas, South Africa, China and other countries
can thrive outdoors year around in Southern
California. Basically, many orchids from lower
latitudes at higher elevations can grow at higher
latitudes at lower elevations. This
temperature comparison chart can help an orchid
grower visualize temperature compatibility in order
to select which species of orchids to try and grow.
In theory, the closer that the temperatures of two
locations align, the more suitable an orchid is for
the orchid grower's location.
Additionally, this resource can also be used to
compare the average temperatures experienced by
orchid growers in two different locations. For
example, an orchid grower in Melbourne, Australia
can compare his/her temperatures to the
temperatures of an orchid grower in Santa Barbara,
CA. If their temperatures are fairly aligned
then they should be able to grow the same orchids.
This temperature comparison chart was primarily
created to assist orchid growers trying to decide
which orchids to grow outdoors year around in nearly
frost free climate. However, it can also help
orchid growers who summer their orchids outdoors to
decide when to take their orchids outdoors and when
to bring them back indoors.
If you already successfully grow an epiphytic
orchid outdoors year around, then there's the
possibility that the chart will not indicate that
the orchid is suitable for your temperatures.
If this is the case, then it's most likely that
somewhere in the orchid's distribution range it
experiences temperatures similar to those of your
own location. If that's not the case, then
there are 2 possibilities. The first
possibility is that the listed distribution range of
that orchid is incomplete. The second
possibility is that somewhere in the orchid's
history its distribution included habitat that
experienced temperatures similar to your own.
Regarding the second possibility, here is a
passage from "The Orchidaceae of The Bahama
Archipelago - Taxonomy, Ecology and Biogeographic
Patterns"....
The Isles of June
epithet, referred to earlier, was severely strained,
when in the early morning hours of 19 January 1977,
seven years after the last entry in Tables II and
III, light snow fell on the islands of Grand Bahama,
Great Abaco and New Providence as well as in
southern Florida. In addition, frost formed in
localized depressions on these islands and on
Andros. This was the first time in recorded
meteorological history that such a phenomenon had
occurred. We visited these islands
approximately one month after this extraordinary
event in order to assess its effect on the tropical
flora. We could find none. We feel this
attests to the surprisingly eurythermal resiliency
of the Bahamian flora and it might suggest that the
remnants of cold-tolerance still exist in the
populations from the Wisconsin glaciation.
Did you have to look up the word 'eurythermal'?
I'll admit that I had to. My text editor has
it underlined in red so it's not even in the spell
check dictionary. According to Merriam-Webster
It means..."tolerating a wide range of
temperatures". Interestingly enough, based on
a Google search, there isn't a single document on
the internet that contains the exact phrase,
"eurythermal orchids". Most of the time people
just say, "temperature tolerant orchids".
Paul Gripp, of the Santa Barbara Orchid Estate
(SBOE), can most likely be credited for popularizing
that term. The next time you visit the SBOE,
have a little fun and tell them that you haven't had
much success growing stenothermal orchids and would
like to try growing some eurythermal orchids.
As you might have guessed...stenothermal is the
opposite of eurythermal.
Back to the Bahamas account...hopefully it should
be evident that even if an orchid's temperatures do
not closely align with your own, it doesn't
necessarily mean that the orchid won't tolerate your
temperatures.
While it would be helpful to have a full history
of an orchid's past distribution, its current
distribution range can be used to approximate its
temperature range. The greater an orchid's
elevation and latitude range, the greater its
temperature range. One exception is when a
large latitude range occurs within the tropics.
This is because temperature, in terms of latitude,
does not vary significantly within the tropics
(between 23N and 23S). In addition to latitude
and elevation, proximity to large bodies of water
also influences temperature. If you create a
chart for a coastal location you'll notice that the
average highs and lows are closer together than for
more inland locations.
In order to find information on an orchid's
elevation and latitude range, the best place to look
is in the Origin / Habitat section in the orchid's
culture sheet. Elevation range is usually
stated but latitude range needs to be derived.
Google Earth is a great free program to look up
the latitudes of the locations listed in the Origin
/ Habitat section.
After you've looked up an orchid's latitude
range, In order to save it for future reference, I
highly recommend adding it to the orchid's entry on
the
Orchids Wiki website. Orchids Wiki is an
orchid encyclopedia website that anybody can
contribute to. Here's how you can add the
information...
- Search for the orchid
- Click on "Edit This Page"
- Add the latitude range to the distribution
section.
- Click on the "Show preview" button.
- If it looks ok click on the "Save page"
button.
Once the latitude and elevation range have been
established, they can be used to approximate an
orchid's temperature range by utilizing the chart
options to change the elevation and/or latitude of a
location. To do so click on the + Options link
and select which location you wish to modify.
The + and - buttons can be used to set whether you
will be adding or subtracting elevation or latitude.
Unfortunately, I haven't yet discovered a reliable
latitude formula to use so you'll notice that the
temperature lines do not flatten the closer you go
to the equator, when in reality, they should.