TeaTreeOil
Well-Known Member
Quality CFLs have a very high PAR(above 80% of light output) rating.
lumen's per sq foot x number of plants
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Roseman
Elite Rolling Society
In Skunk Magazine, this month, Ed Rosenthal says:
In the new Skunk there was a question in the "Ask Ed" section that just made my night last night when reading it...
The question was...
Tiny Grow Space
I intend to grow a single cannabis plant in a space 1' x 2'. What light would you recommend? I was think of using four 30-watt compact fluorescent lamps. Will this be enough? Cost isn't an issue but I am deterred from getting a high pressure sodium [light] because of the amount of heat the bulb produces.
Barry, Internet
As you mentioned, you have several lighting systems to choose from, including compact fluorescents and high pressure sodium (HPS) lamps. Among HPS lamps you have a choice between a single 100-watt lamp which uses a total of about 120-watts and emits about 8,800 lumens(73 lumens per watt) or a 150-watt lamp, which uses about 180 watts and emits almost double that-15,800 lumens (87 lumens per watt).
A 42-watt compact fluorescent (CFL) emits about 2700 lumens(64 lumens per watt). Four CFLs use 168 watts and emit 10,800 lumens. Other size CFLs have a similar efficiency.
However, that is only part of the story. Plants use mostly red and blue light. Yellow and green light is of little use to them, so light that is emitted in these spectrums is wasted energy. Most of the light emitted by HPS lamps is in the yellow spectrum. Only a small amount of the emitted light is is in the orange or red spectrums, which plants use efficiently. Warm white fluorescents (2700 Kelvin) emit a greater portion in the red and orange sectors.
Although fluorescents produce only about 75% of the light per watt that the HPS does, the amount of light usable by the plant is equal or probably higher with the fluorescents. You may wish to experiment to see if adding a single cool white CFL to replace one warm white results in shorter, stouter stems and more vigorous growth. The reasoning is that warm whites don't emit much blue light, which the plants use for photosynthesis and to regulate their growth. The cool white bulb supplies the blue light.
My call for your unit would be to use several (three to five) CFLs with a total input of between 120-160 watts. Although the 150 watt HPS is a bit more efficient that the CFLs in total output, watt for watt the fluorescents provide as much useful light as the HPS lamp. Heat is another consideration. The HPS runs much hotter and emits more heat than the fluoescents.
Make sure to use reflective material around the garden so that any light escaping the garden is reflected back to the plants. Any light that doesn't get to the plant leaves is wasted.
In the new Skunk there was a question in the "Ask Ed" section that just made my night last night when reading it...
The question was...
Tiny Grow Space
I intend to grow a single cannabis plant in a space 1' x 2'. What light would you recommend? I was think of using four 30-watt compact fluorescent lamps. Will this be enough? Cost isn't an issue but I am deterred from getting a high pressure sodium [light] because of the amount of heat the bulb produces.
Barry, Internet
As you mentioned, you have several lighting systems to choose from, including compact fluorescents and high pressure sodium (HPS) lamps. Among HPS lamps you have a choice between a single 100-watt lamp which uses a total of about 120-watts and emits about 8,800 lumens(73 lumens per watt) or a 150-watt lamp, which uses about 180 watts and emits almost double that-15,800 lumens (87 lumens per watt).
A 42-watt compact fluorescent (CFL) emits about 2700 lumens(64 lumens per watt). Four CFLs use 168 watts and emit 10,800 lumens. Other size CFLs have a similar efficiency.
However, that is only part of the story. Plants use mostly red and blue light. Yellow and green light is of little use to them, so light that is emitted in these spectrums is wasted energy. Most of the light emitted by HPS lamps is in the yellow spectrum. Only a small amount of the emitted light is is in the orange or red spectrums, which plants use efficiently. Warm white fluorescents (2700 Kelvin) emit a greater portion in the red and orange sectors.
Although fluorescents produce only about 75% of the light per watt that the HPS does, the amount of light usable by the plant is equal or probably higher with the fluorescents. You may wish to experiment to see if adding a single cool white CFL to replace one warm white results in shorter, stouter stems and more vigorous growth. The reasoning is that warm whites don't emit much blue light, which the plants use for photosynthesis and to regulate their growth. The cool white bulb supplies the blue light.
My call for your unit would be to use several (three to five) CFLs with a total input of between 120-160 watts. Although the 150 watt HPS is a bit more efficient that the CFLs in total output, watt for watt the fluorescents provide as much useful light as the HPS lamp. Heat is another consideration. The HPS runs much hotter and emits more heat than the fluoescents.
Make sure to use reflective material around the garden so that any light escaping the garden is reflected back to the plants. Any light that doesn't get to the plant leaves is wasted.
Brick Top
New Member
They key word to what you said above was "quality" and unfortunately not everyone knows what lighting is "quality" and buys "quality" or can afford "quality" so they still need to keep par lumens in mind more than lux lumens.
TeaTreeOil
Well-Known Member
According to independent studies they're nearly identical to other CFLs.
By quality I meant like GE Daylight/Aquarium/Plant bulbs.... Any name brand. Now the housebrand/generic. You'll see a 20% improvement with name brand over generics. You'll feel more heat from these generics too.
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