Cool, Intermediate, Warm, Hot growers?

[Stevie_White]

Looking at various orchid nursery sites and watching Youtube videos I hear many people mentioning certain orchids at Warm growers, Hot growers, Cool to Warm growers, etc. Is there a generally accepted range that each of these terms fall in? It would be helpful when looking at possibly purchasing orchids to know how they might grow in my apartment.

For reference I live in NW Idaho and keep my apartment at about 24C/75F. Does that fall in the warm range, hot range? Am I keeping my unit too warm to grow a Cool growing orchid?

[Subrosa]

75°F falls within the range of cool, intermediate and warm growers. Cool growers will be quite happy with with a daytime high of 75°F, provided the temperature drops 20°-25° or so at night. Warm growers will be quite happy with a night time low of 75° F.

[estación seca]

Most plants in habitat have noticeable day/night temperature swings. Horticultural temperature ranges for orchids are usually defined by night temperatures. They are approximate.

With some species a day/night temperature swing is very important; with others it isn't.

Light is a factor. It's hard to provide high light without heat. Cold and cool growing orchids are harder to keep happy in many homes without cooled terrariums. Intermediate and warm growers are easiest to keep happy in most homes. Hot growers usually need extra heat during the day to be happy in a home.

Extra heat affects humidity; most orchids prefer higher humidity than found in most homes, but many will grow in the 40% range.

Cold often means below about 45-50 F at night; cool about 45-55 at night; intermediate about 55-65 at night; warm about 60-70 at night; hot about 70+ at night. Days should be warmer.

Hybrids often have ancestors from various temperature ranges. They tend to be more temperature adaptable than species, and are less fussy about day/night swings.

When selecting orchids consider the light and day/night temperatures, summer and winter, you have. In homes kept at a constant temperature all year, intermediate growing hybrids and species, suitable for the light available, will be most successful. Some cool and warm growers, especially hybrids, will grow and flower. I would avoid cold and hot growers unless you're willing to control the temperature in a terrarium.

You will have a problem with winter light, being so far north. Most orchids prefer longer winter days than you have. You will be able to grow lower light plants, but higher light plants will need supplemental lighting.

Humidity may be a problem. An ultrasonic humidifier pointed at your plants will help a lot. So-called humidity trays don't raise humidity, but they do keep water off your furniture.

Most Phalaenopsis should grow well for you. Likewise most Oncidium intergeneric hybrids, which need more light than do Phals. Some smaller Vanda hybrids and Neofinetia will flower if your summer window light is bright enough. You may be able to grow Masdevallias and Zygopetalums if you raise your humidity. Warmth tolerant and Chinese Cymbidiums will flower for you, but many are large plants.

You won't be able to flower most Cattleya alliance plants without supplemental lights. They won't flower with short winter days.

What plants are you thinking of?

[Stevie_White]

Thanks for your help.

I'm still new to having orchids so I'm not very set on any specific type. I do have 3 phals and 2 oncidiums at the moment. I use a growing light during the day from about 6/7 am to 7/8 pm to give them extra light while I'm at work since there isn't much coming from the window.

I have thought of getting a dendrobium next, but I will have to revisit their growing conditions. I will also set my temps in my unit to drop a bit at night, which it sounds like the plants might appreciate.

[Ray]

I think the temperature classifications mostly refer to nighttime minimums, but of course, the daytime maximum temperatures usually track with them, with plants from higher altitude origins often having greater diurnal variation.

[estación seca]

There are a lot of different kinds of Dendrobium. Some need very cool winters to flower, and can be hard to bloom in a home. Three kinds that do well in a lot of homes are Antennatum/antelopes, Latourias and Den phal hybrids. These don't have dormancy requirements and do well with even temperatures, watering and light.

[Orchidtinkerer]

I have grouped my orchids into 6 different groups,

- cool growers with low light
- cool growers with high light
- warm to cool growers - this does not mean it can handle warm or cold, this means warm day time temps and cold nights
- hot to cool growers (hot days, cold nights)
- warm growers
- hot growers

I have copied a few examples that would fall into each category:

Hot : (lots of heat day and night all year)(min 16 C night, day 26-28) – 12 hour days all year 3500fc

Phalaenopsis Corningiana
Phalaenopsis cornu-cervi var chatteladea
Dendrobium phalaenopsis
Chytrogolossa aurata
Angraecum didierii
Angraecum leonis
Brassavola cuculata

Brassavola Flagellaris
Brassavola Little Stars
Blc Ports of Paradise
Blc Shinfong Gold Gem
Dendrobium Anosmum
Dendrobium Sanook Blue Happiness
Rhynchostylis Gigantea
Bifrenaria aureo-fulva
Encyclia Fragrans
Vanda Ploenpit Prize
Phalaenopsis Liodora
Cattleya Luteola

Medium (same as hot just less daytime heat~24C,min 16C deg at night) – 12 hour days all year
All year

Phal Bellina
Phal Violacea
oncidium cheirophorum
Aerides Houllettiana
Angreaecum Longiscott
Dendrobium Atroviolaceum
Cattleya Labiata

Hot to cool difference : High heat days(26-27), cold nights, colder winter nights(13C minimum), 9 hrs in winter, 12-15hrs in summer, 2500-3500fc

Neofinetia Falcata
Vanda Denisoniana
Vandopsis parishii
Sedirea Japonica
Dendrobium Normanbyense
Dendrobium Aggregatum
Laelia lundii
Vanda Sukontharat
Vanda Batram
Dendrobium Harveyanum
Vanda Pumilla

Medium to Cool: same as hot to cold, just less day time heat(24C), same photoperiod regime, 3000fc

Vanda coerulescens
Dendrobium Falconostrum
Dendrobium Parishii
Mexicoa ghiesbreghtiana
Dendrobium moniliforme
Aerangis citrata (2000fc)
Aerangis fastuosa (2000fc)
Angraecum compactum (2000fc)
angraecum rutenbergianum
phalaenopsis mannii(1000fc)
Cyrtorchis arcuata
Dendrobium jenkinsii
haraella retrocalla

Maxillaria Tenuifolia (4000fc)
Guarianthe Aurantiaca (3500fc)
Angraecum Magdalenae (4 deg diff)
Cattleya Jenmannii (4deg diff)(2.5-3.5k foot candles)
rhynchostylis coelestis

Cool european climate – windowsill - highly dependent on cold temps & photoperiod (10 degrees minimum)

Low light:
Aerangis Mystacidii
Oncidium Sharry baby
Maxillaria Marghinata
Maxillaria Picta
Odontoglossum chayenne
Encyclia Garciana
Oncidium Tiny Twinkle
Pabstia Jugosa

High light:

Dendrobium Chrysotoxum
Dendrobium Chrysanthum
Dendrobium Brymerianum
Gongora Galeata
Slc Jewel Box
Laelia Xanthina
Rhyncholaelia Glauca (80k lux)
Blc Prapa Green
Cattleya Nobilior (50-70000lux)
Cattleya Maxima (10 drg diff minimum)(2-4kfc)
Sophronitis coccinea
Potinara Burana Beauty

Most Cymbidiums

Ps: I should add that some varieties should stick to the group they are in or they won't do as well but others like the Oncidium Tiny Twinkle for example will grow well in pretty much any climate. It's a rough guide and if you need to research whether a variety I listed can handle something slightly different, the information can be easily found on google these days

[Subrosa]

Originally Posted by Orchidtinkerer

I have grouped my orchids into 6 different groups,

- cold growers with low light
- cold growers with high light
- warm to cold growers - this does not mean it can handle warm or cold, this means warm day time temps and cold nights
- hot to cold growers (hot days, cold nights)
- warm growers
- hot growers

I have copied a few examples that would fall into each category:

Hot : (lots of heat day and night all year)(min 16 C night, day 26-28) – 12 hour days all year 3500fc

Phalaenopsis Corningiana
Phalaenopsis cornu-cervi var chatteladea
Dendrobium phalaenopsis
Chytrogolossa aurata
Angraecum didierii
Angraecum leonis
Brassavola cuculata

Brassavola Flagellaris
Brassavola Little Stars
Blc Ports of Paradise
Blc Shinfong Gold Gem
Dendrobium Anosmum
Dendrobium Sanook Blue Happiness
Rhynchostylis Gigantea
Bifrenaria aureo-fulva
Encyclia Fragrans
Vanda Ploenpit Prize
Phalaenopsis Liodora
Cattleya Luteola

Medium (same as hot just less daytime heat~24C,min 16C deg at night) – 12 hour days all year
All year

Phal Bellina
Phal Violacea
oncidium cheirophorum
Aerides Houllettiana
Angreaecum Longiscott
Dendrobium Atroviolaceum
Cattleya Labiata

Hot to cold difference : High heat days(26-27), cold nights, colder winter nights(13C minimum), 9 hrs in winter, 12-15hrs in summer, 2500-3500fc

Neofinetia Falcata
Vanda Denisoniana
Vandopsis parishii
Sedirea Japonica
Dendrobium Normanbyense
Dendrobium Aggregatum
Laelia lundii
Vanda Sukontharat
Vanda Batram
Dendrobium Harveyanum
Vanda Pumilla

Medium to Cold: same as hot to cold, just less day time heat(24C), same photoperiod regime, 3000fc

Vanda coerulescens
Dendrobium Falconostrum
Dendrobium Parishii
Mexicoa ghiesbreghtiana
Dendrobium moniliforme
Aerangis citrata (2000fc)
Aerangis fastuosa (2000fc)
Angraecum compactum (2000fc)
angraecum rutenbergianum
phalaenopsis mannii(1000fc)
Cyrtorchis arcuata
Dendrobium jenkinsii
haraella retrocalla

Maxillaria Tenuifolia (4000fc)
Guarianthe Aurantiaca (3500fc)
Angraecum Magdalenae (4 deg diff)
Cattleya Jenmannii (4deg diff)(2.5-3.5k foot candles)
rhynchostylis coelestis

Cold european climate – windowsill - highly dependent on cold temps & photoperiod (10 degrees minimum)

Low light:
Aerangis Mystacidii
Oncidium Sharry baby
Maxillaria Marghinata
Maxillaria Picta
Odontoglossum chayenne
Encyclia Garciana
Oncidium Tiny Twinkle
Pabstia Jugosa

High light:

Dendrobium Chrysotoxum
Dendrobium Chrysanthum
Dendrobium Brymerianum
Gongora Galeata
Slc Jewel Box
Laelia Xanthina
Rhyncholaelia Glauca (80k lux)
Blc Prapa Green
Cattleya Nobilior (50-70000lux)
Cattleya Maxima (10 drg diff minimum)(2-4kfc)
Sophronitis coccinea
Potinara Burana Beauty

Most Cymbidiums

Ps: I should add that some varieties should stick to the group they are in or they won't do as well but others like the Oncidium Tiny Twinkle for example will grow well in pretty much any climate. It's a rough guide and if you need to research whether a variety I listed can handle something slightly different, the information can be easily found on google these days

There's a big difference between cool growers and cold growers. My cold growers are outside in the ground and see winter temps below -10°F/ -20°C.

[Stevie_White]

Thank you all for the advice. It can be difficult when looking at listings or watching videos, because these terms are often used without much explanation. When I looked temperature ranges up on the American Orchid Societies website they only listed information on Warm, Intermediate and Cool growers. I was left going "... Wait.... Where's the information on Hot growers?"
Temperature Ranges

Since I keep my apartment at the 24C/75F range during the day, and closer to 17C/62F at night it seems like I should be fine with most cool and warm growers, but might have difficulty with hot. I'll just also have to look at an orchids light requirements as well (though I could use artificial light if neeced.)

Thanks again everyone!

[estación seca]

Heat pads can help a lot.