Light quality in plant growing is very important. Photosynthetic pigments such as chlorophyll absorb definite parts of spectrum. The most intense absorption is within red and blue parts of spectrum, green is reflected (that’s why plant’s photosynthetic parts have intense green color). That’s why some, special orchid grow lights are suitable for orchid growing ( they are also excellent grow lights for other house plants) – they have special, photosynthesis-optimized spectrum with peaks at red and blue parts of the spectrum. So, indoor grow lights should have photosynthesis-optimized spectrum (so called phytolamps). Another important thing about artificial light is its efficiency. For instance, incandescent lamps produce more heat than light, and therefore not efficient and could not be used either for additional light source or for full light as they do not produce much light and produce too much heat. Sodium-vapor lamps on one hand are very effective – they have 100 lm/W efficiency and rather good spectrum, but are rather expensive, in addition although their spectrum is chlorophyll-friendly, it is not eye-friendly – and they can be rather dangerous in use. So, they are used by professional plant growers at greenhouses, by vendors, because they can effectively replace natural sunlight, but not very suitable for indoor garden, but rather for spetial orchid grow room. If you use sodium-vapor lamps, it’s better to protect your eyes with spetial glasses
Metal-halide lamp systems are also suitable only for professionals – they are costly, not user-friendly, but they are very effective – 75 – 100 lumens per watt.
Fluorescent grow lights
Fluorescent grow lights (also known as hydroponic grow lights) are very popular as they are cheap, user-friendly, they come in different spectra (there are some models, factored especially for indoor grow lights systems for plant growing), they have great efficiency – 100 lumens per watt. There are also plant-oriented compact fluorescent light (CFL) – so called CFL grow lights for orchid growing.
Fluorescent grow lights for sale
LED grow lights
Also, there are light-emitting diode (LED) – based light systems for indoor plant growing. They have great efficiency – 80 to 120 lumen per watt, but in the past there were some considerations about using LED for plant growing as it is monochromatic light source with poor spectrum. But now, LED grow lights for sale have balanced spectrum. The best LED grow lights are considered the good choice for indoor use, and there is some tendency in switching from not very eco-friendly fluorescent lamps to LEDs.
LED grow lights for sale
AROCCOM Advanced LED Plant Grow Light for Hydroponic Garden and Greenhouse Use – 12W, E27 socket, 3 Bands. Perfect spectrum plant growth system Grow Lights for Indoor Plants – 12W E27 – 12 LEDS (3 Blue & 9 Red)
Full spectrum Kind LED grow lights | K3 – L300 – 300w HPS
Indoor grow tent system
Light intensity is measured in foot candles, and different orchid species need different amount of foot candles. For instance, Vandas and unifoliate Cattleyas need high light – 4000 to 6000 foot candles. Oncidium Alliance orchids, Dendrobiums, bifoliate Cattleyas thrive under medium light – 2000 to 4000 foot candles. Jewel orchids, Phalaenopsis and most Paphiopedilum prefer low light (1500 foot candles). It’s a very good idea to buy light meter to control light intensity. In most cases, eastern and western windowsills are the best for most orchids as they provide medium light, northern windows provide sufficient light only for Phalaenopsis and Jewel orchids, and southern windows are the best for Vandas and Cattleyas. But if your windows are shaded by other buildings, threes and so on, even southern windows might not provide sufficient light. So it is good to measure light intensity with light meter to be certain.
Most orchids are tropical plants so they need about 12 hours of light daily year-round. In temperate areas there is some imbalance – at summer day duration is 16 hours (which is OK for most orchids except some species Labiata-group Cattleyas which are short-day plants and do’t produce flowers when day duration is more than 12 hours). And in winter is 8 hours, which is not sufficient for most orchids. Some orchids which have profound dormancy at winter could tolerate short day and low light intensity, but most orchids need additional light to cover their needs in day duration and light intensity, so orchid grow lights will be needed.
Growing Orchids Under Lights
Charles Marden Fitch