chitownturk
Active Member
THat bulb's PPFD isn't good enough for me to want to use it
Short Solution:
Use a "Osram Plantastar 600 watt HPS", it's got the highest rated PPF/D of any current bulb and it's ASP range is weighted well.
Long Answer: (lol)
Plants use photons in the wavelength from about 400-500nm and 600-700nm. But plants don't use these two ranges equally, the ranges have different "weight" in terms of plant usefulness: the blue (400-500nm) and red (600-700nm) are weighted differently. The jury is still out on what is best but IMVHO 55% blue and 45% red is a good way to go...or 60%:40%...I like more blue at all phases but I'm happy with anything from 40%:60% (blue:red) to 60%:40% (blue:red). Both ranges have to be there in good amounts. The plant will adjust to what is present, just like it does with chemical nutrients in the media and in it's interaction with microbes/myco's from which the plants receive nutrients in organic horticulture...
There is much evidence that plants are somewhat indifferent to the ranges of photons; as long as both ranges are there in good quantities the plant will auto-adjust to best use the available nanometers...as long as they are within the ranges of 400-500nm and 600-700nm...
Those two rages of 400-500nm and 600-700nm are the "Action Spectra of Photosynthesis" (ASP). Those two ranges are also "Chlorophyll Carotenoids Absorption Spectra" (CCAS) . 400-500nm and 600-700nm are the two ranges we are interested in, you can see why they are important. Wavelengths emitted outside these two ranges are a waste of light and energy... Well, uvb and uva are important too, but not relevant to this thread.
lumes are a poor measurement of a bulbs plant usefulness, plants don't use lumens they use photons. Lumens include a wide range of wavelengths the plants don't use...
To measure a bulbs usefulness for growing plants in terms of energy output in photons you want to know the bulbs "Photosynthetic Photon Flux" (PPF) or more specifically the "Photosynthetic Photon Flux Density" (PPFD). The PPF tells you how many moles (method of measurement of photons) are being emitted per sq meter and the PPFD tells you how many moles are being emitted per sq meter and per second. PPFD is the best as it not only tells you what nanometers are emitted but how many moles are emitted in a given space and time which translates into the 'strength' of the bulb as more photons = more growth...PPF and PPFD measure the two rages of 400-500nm and 600-700nm.
A problem with PPF/D is it measures the photons at the source (eg. blulb); that is why we need to measure 3D PPFD as it encompasses moles at various distances from the source (see below).
There is also PAR (Photosynthetically active radiation) which measures the wavelength emitted but it covers 400-700nm which is a waste as the two ranges we want are 400-500nm and 600-700nm. So PAR isn't that good of a measurement for many reasons besides just the fact it 'overweights' wavelentgs from 400-700nm.
There are other factors to consider but it gets even more confusing and I don't really get it all either; just enough to know theres more I don't fully understand. There are a few equations used to correct the 'weight' of the two ranges within PAR and PPFD to more accurately portray what the plant needs in terms of nanometers (specific wavelengths)...but to keep things more simple just follow what I posted above: Try to get a PPFD with 40-60% blue:red or red:blue; but PPFD isn't measured like that, it's just a single mole measurement. Higher PPFD is better. Soooo you also NEED to see the "spectral output" of the bulb so you can get an idea of how the two ranges within PPF/D are weighted: that is, what percent of the total PPF/D do the blue (400-500nm) and red (600-700nm) ranges comprise?
Some bulb manufactures list the PPF and fewer list the PPFD and most do not list either...many list PAR which isn't useful unless you analyze the spectral output and then do some math kung-fu to figure out how the bulb is weighted in terms of the blue and red ranges comprising PPF/D. Thats the crappy part, most bulb manufactures don't have a quantum meter used to measure PAR and PPFD. And even fewer have 3D quantum meter (aka "line quantum meter") which measures level of PPFD at different depths within the canopy (distance from source).
Hell, most bulb manufactures don't even know or care about the level of PPFD and how the ranges are weighted. I spoke to like 3 different bulb manufactures and not one had a quantum meter and only one had a scientist on staff who knew what a quantum meter is...
Anyway, like I said at first:
Get an Osram Plantastar 600 watt...that's the only bulb I want to veg/flower under...and if you want a ferrari go with an air-cooled P.L. "Maxima" reflector/hood and a Lumitech digital ballest with your Plantastar 600 watt bulb
Osram is a major light manufacturer in Holland and they designed Plantastar specifically for plants to maximize the PPFD...this is the ONLY bulb designed with PPF/D in mind when designing the bulb, that I am aware of...
Short Solution:
Use a "Osram Plantastar 600 watt HPS", it's got the highest rated PPF/D of any current bulb and it's ASP range is weighted well.
Long Answer: (lol)
Plants use photons in the wavelength from about 400-500nm and 600-700nm. But plants don't use these two ranges equally, the ranges have different "weight" in terms of plant usefulness: the blue (400-500nm) and red (600-700nm) are weighted differently. The jury is still out on what is best but IMVHO 55% blue and 45% red is a good way to go...or 60%:40%...I like more blue at all phases but I'm happy with anything from 40%:60% (blue:red) to 60%:40% (blue:red). Both ranges have to be there in good amounts. The plant will adjust to what is present, just like it does with chemical nutrients in the media and in it's interaction with microbes/myco's from which the plants receive nutrients in organic horticulture...
There is much evidence that plants are somewhat indifferent to the ranges of photons; as long as both ranges are there in good quantities the plant will auto-adjust to best use the available nanometers...as long as they are within the ranges of 400-500nm and 600-700nm...
Those two rages of 400-500nm and 600-700nm are the "Action Spectra of Photosynthesis" (ASP). Those two ranges are also "Chlorophyll Carotenoids Absorption Spectra" (CCAS) . 400-500nm and 600-700nm are the two ranges we are interested in, you can see why they are important. Wavelengths emitted outside these two ranges are a waste of light and energy... Well, uvb and uva are important too, but not relevant to this thread.
lumes are a poor measurement of a bulbs plant usefulness, plants don't use lumens they use photons. Lumens include a wide range of wavelengths the plants don't use...
To measure a bulbs usefulness for growing plants in terms of energy output in photons you want to know the bulbs "Photosynthetic Photon Flux" (PPF) or more specifically the "Photosynthetic Photon Flux Density" (PPFD). The PPF tells you how many moles (method of measurement of photons) are being emitted per sq meter and the PPFD tells you how many moles are being emitted per sq meter and per second. PPFD is the best as it not only tells you what nanometers are emitted but how many moles are emitted in a given space and time which translates into the 'strength' of the bulb as more photons = more growth...PPF and PPFD measure the two rages of 400-500nm and 600-700nm.
A problem with PPF/D is it measures the photons at the source (eg. blulb); that is why we need to measure 3D PPFD as it encompasses moles at various distances from the source (see below).
There is also PAR (Photosynthetically active radiation) which measures the wavelength emitted but it covers 400-700nm which is a waste as the two ranges we want are 400-500nm and 600-700nm. So PAR isn't that good of a measurement for many reasons besides just the fact it 'overweights' wavelentgs from 400-700nm.
There are other factors to consider but it gets even more confusing and I don't really get it all either; just enough to know theres more I don't fully understand. There are a few equations used to correct the 'weight' of the two ranges within PAR and PPFD to more accurately portray what the plant needs in terms of nanometers (specific wavelengths)...but to keep things more simple just follow what I posted above: Try to get a PPFD with 40-60% blue:red or red:blue; but PPFD isn't measured like that, it's just a single mole measurement. Higher PPFD is better. Soooo you also NEED to see the "spectral output" of the bulb so you can get an idea of how the two ranges within PPF/D are weighted: that is, what percent of the total PPF/D do the blue (400-500nm) and red (600-700nm) ranges comprise?
Some bulb manufactures list the PPF and fewer list the PPFD and most do not list either...many list PAR which isn't useful unless you analyze the spectral output and then do some math kung-fu to figure out how the bulb is weighted in terms of the blue and red ranges comprising PPF/D. Thats the crappy part, most bulb manufactures don't have a quantum meter used to measure PAR and PPFD. And even fewer have 3D quantum meter (aka "line quantum meter") which measures level of PPFD at different depths within the canopy (distance from source).
Hell, most bulb manufactures don't even know or care about the level of PPFD and how the ranges are weighted. I spoke to like 3 different bulb manufactures and not one had a quantum meter and only one had a scientist on staff who knew what a quantum meter is...
Anyway, like I said at first:
Get an Osram Plantastar 600 watt...that's the only bulb I want to veg/flower under...and if you want a ferrari go with an air-cooled P.L. "Maxima" reflector/hood and a Lumitech digital ballest with your Plantastar 600 watt bulb
Osram is a major light manufacturer in Holland and they designed Plantastar specifically for plants to maximize the PPFD...this is the ONLY bulb designed with PPF/D in mind when designing the bulb, that I am aware of...