merely a guideline; if you’re off by a few degrees, especially the high degrees during the day during the summer, don’t worry about it. Orchids are adaptable.
TABLE 2-1 Orchid Temperature Preferences
| Temperature (Nighttime Minimum) | Genus |
|---|---|
| Cool (45°F–55°F/7.2°C–12.8°C) | Cymbidium Dendrobium Odontoglossum |
| Cool (45°F–55°F/7.2°C–12.8°C) to Intermediate (55°F–60°F/12.8°C–15.6°C) | Cymbidium Dendrobium Encyclia Masdevallia Miltoniopsis Zygopetalum |
| Intermediate (55°F–60°F/12.8°C–15.6°C) | Aerangis Cattleya and hybrids Cymbidium Dendrobium Encyclia Epidendrum Laelia Maxillaria Miltonia Oncidium Paphiopedilum Phragmipedium Vanda Zygopetalum |
| Intermediate (55°F–60°F/12.8°C–15.6°C) to Warm (65°F/18.3°C or higher) | Aerangis Amesiella Angraecum Brassavola Cattleya Dendrobium Encyclia Epidendrum Neofinetia Neostylis Oncidium Rhynchostylis Vanda Vascostylis |
| Warm (65°F/18.3°C or higher) | Angraecum Phalaenopsis Vanda |
Measuring your light intensity
Just as important as temperature is the amount of light your orchid will get. Orchids that thrive in high light need several hours of direct sunlight (preferably in the morning to early afternoon), or bright artificial light whereas those that thrive in lower light will perform with less direct and more diffused light in a windowsill or under less intense lights.
Will you be growing the plants under artificial lights? Most light setups consist of multiple florescent high-output lamps and LEDs, and they can provide adequate illumination to most orchids. High-intensity-discharge lamps are capable of much more light output but can be expensive to operate and generate quite a bit of heat. For most folks the best option is going to be LED or various fluorescent bulb units. For much more details about lighting, see Chapter 5.
© John Wiley & Sons, Inc.
FIGURE 2-2: The shadow test is a simple and reasonably accurate way to measure light intensity.
After you determine your light levels, turn to the following sections, which list orchids by the amount of light they need. Remember to keep in mind temperature (see the preceding section).
A more exact way to measure light is to purchase a handheld light meter (see Figure 2-3). You can purchase several modestly priced models, including free apps for your phone. I prefer the handheld models because they’re so easy to use.
© John Wiley & Sons, Inc.
FIGURE 2-3: An example of a handheld light meter.
The most common measure of light intensity is footcandles, which is equivalent to the light emitted by one candle one foot away. This is an old English measure that is still used today and what most light meters read.
Professional and very serious light gardeners use other more exact light measurements but, frankly, in most cases for home growers you don’t need to use them.
Bright light (5000 to 6000 footcandles)
The following orchids require a bright greenhouse, a very bright south-facing window, or four or more high-intensity fluorescent lamps, large banks of LEDs, or metal halide lamps (see Chapter 5):
Angraecum
Some varieties of Cymbidium
Some varieties of Dendrobium
Vanda
Medium light (2500 to 3000 footcandles)
The following orchids need a shaded greenhouse, a large east-facing window during the spring, summer, and early fall window or a four-tube florescent light fixture or LEDs of the same light output: (In the winter during shorter days and lower light the greenhouse needs to have some shade material removed, and plants can be moved to a brighter south window, or you can continue growing them under lights.)
Amesiella
Ascocenda
Ascocentrum
Ascofinetia
Brassavola
Brassia
Cattleya and hybrids
Some varieties of Cymbidium
Some varieties of Dendrobium
Epidendrum