Again, QFT
That and in my opinion the SPD should be reported by PPFD not watt/meter^2 (aka PAR watts). Also, it should be listed what type of ballast (magnetic vs digital) is used.
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Why has there been no major advances in HPS bulbs?
- Thread starter pokergod
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Again, QFT
That and in my opinion the SPD should be reported by PPFD not watt/meter^2 (aka PAR watts). Also, it should be listed what type of ballast (magnetic vs digital) is used.
I think lamp efficiency, be it HID or LED, should be a separate issue from a lamp effectiveness in producing highest rate of photosynthesis (both from SPD and irradiance). Lamp efficiency in turning electricity into PAR range photons is about a grower's wallet (i.e., electric bill); lamp effectiveness in turning electricity into photosynthesis is about a grower's plants.
My 2 cents: I would rather use a less efficient lamp with higher plant effectiveness than a more efficient lamp with lower plant effectiveness.
In terms of carbon footprint from a less efficient lamp I offset my grows by buying carbon credits, so my grows are carbon negative
FWIW, I listed the best quantum sensor for under a few thousand dollars in a post above. Using umol radiance (PPF) along with umol irradiance (e.g., PPFD) is the best route. And adding a umol fluence quantum sensor (a near omnidirectional sensor; looks like a incandescent light bulb) is even better for "whole canopy" light measurements vs simply top canopy light measurements with a 'normal' quantum sensor.
The cheapest quantum sensor I know of is from SpecMeter, it's ~$200 and it's a quantum sensor and light meter in one. However, it's very inaccurate due to it's poor quantum response. Apogee makes a better quantum sensor/light meter combo for ~$300 but it too has a poor quantum response. Thus neither are really any good.
Custom Hydroponics rents the Apogee quantum sensor/light meter combo for $25 a week with a $250 deposit. Even though the quantum response under-values blue and red light it's much better than using a lux meter or using Lumens.
Lumens are for humans.
All those bulb manufacturers with Chinese crap they dont even have a output in µMol.
The bulbs without µMol is made for streetlighting.
The µMol/PAR output is the horticultural way for measuring bulbs for over 7 years.
Any company that doesnt release this information is a hype company.
The standard measurements of light output have traditionally been done through the foot-candle, lumens and lux. They quantify how humans experience the intensity of light, based on the limited sensitivity of the human eye in the yellow/green area of the spectrum (around 550 nm). Plants however use a much wider spectrum for photosynthesis, called the PAR spectrum (Photo-synthetically Active Radiation), ranging from 400-700 nm
Human eye sensitivity versus plant sensitivity
Photosynthesis is not driven by brightness of the light according to the human eye or the energy of a photon (which varies for different colors) but purely by the number of photons in the PAR spectrum. You need about eight photons to bind one CO2 molecule. So to quantify potential photosynthesis it is all about the number of photons within the PAR spectrum hitting the plant. This is expressed as Photosynthetic Photon Flux (PPF – total photons emitted from a light source per second) and Photosynthetic Photon Flux Density (PPFD – the number of photons hitting one square meter of surface per second) and it is measured in moles or micromoles (µmol) of photons.
You can measure the number of photons hitting your plant (PPFD) using a quantum meter, predicting the potential photosynthetic capacity of your light.
You can measure the total number of photons emitted by a lamp (PPF)by putting it in an Ulbricht integrating sphere
So where we used to have luminous flux in lumens, we now have PPF in µmol/s, and where we used to have illuminance (light indicent on a surface) in lux, we now have PPFD in µmol/m2/s
Lamps with high lumens output are not necessary high par output lamps: some lamps with lower lumens output have higher micromole output.
Another important issue is of course the spectrum of a lamp. Micromoles alone is not enough - or blue and red LEDs would have worked
Doc
Hey there Doc,
FWIW, that graph for plants is flawed because it's based on the Chl A/B absorption spectra and absorption spectra of a limited number of accessory pigments; not upon quantum yield of photons per wavelength. Green light is only slightly lower in quantum yield than blue light and both blue and green light have lower quantum yield than red light; but not by much. Yellow-orange light drives Pn (rate of photosynthesis) well, the quantum yield is higher than blue and green light for most higher plants.
Also, under near light salutation (e.g., ~ 1,200-1,500 umol/area/second) green light can have higher quantum yield than both blue and red; that is, green light can drive photosynthesis better than blue and red due to acting upon lower chloroplasts in leaves.
See the graphs I posted for what we should use for judging SPDs of lamps. The myth that plants don't use green light for photosynthesis (at all, or at least well) is based upon the Chl A/B absorption spectra.
See this thread of mine for more info:
Avoid Misconceptions When Teaching About Plants
I can tell you the radiance (PPF) of new Digilux 1,000w lamps in a few days, for both the 1,000w MH and 1,000w HPS, with a Galaxy select-a-watt digital ballast.
That data sheet is correct, they wrote "enhanced red and orange spectrum" for the MH lamp SPD and "enhanced blue spectrum" for the HPS lamp SPD.
FWIW, I really like the box they come in; the lamps are sitting in custom molded box interior.
1,000w MH or HPS depending upon SPD and radiance; the higher wattage can mean sufficient irradiance for cannabis over the canopy with a good reflector (i.e., > 1,200 umol/area/second; 1,500 umol/area/second is ideal for instantaneous light).
As well as a UV-b lamp providing ~10-13+ kiloJoule/day for cryptochrome* mediated responses, a large increase in THC and stocky plants. UV-b can also bring out colors in buds and leaves due to affecting/increasing "anthocyanin" pigments. Anthocyanin pigments, like many flavonoids, are UV-b 'screening' pigments, thus under UV-b anthocyanin and flavonoids are increased in buds and leaves.
* Cryptochrome are blue light receptors and cryptochrome responses are blue light mediated responses such as increased stomatal conductance (stoma open wider), stocky plants and affects on flowering. UV-b, UV-a and low PAR range wavelengths affect can cryptochrome.
Also, using a digital ballast and lamps designed for a digital ballast is better due to less flicker, no issues with hot-starting, higher radiance, etc.
In general MH is better than HPS, that is, if they both are 'enhanced' for plants and both provide sufficient irradiance (as listed above). MH is generally better in terms of red:far-red ratio intracanopy (MH normally has less far-red radiance than HPS) which greatly affects plants stretching, especially in pre-flowering. We want a high red:far-red ratio intracanopy; at least 1:1 is ideal but that won't happen, if we can get > 0.25:1 red:far-red we are doing well...
Far-red light in terms of phytochrome B mediated responses (such as induction of flowering) is ~720-740 nanometers (nm).
Doc420
Member
@spurr
Dont you need a ulbricht sphere to get the umol data??
You can measure Par=Photosynthetically active radiation with the quantum meter Par=(uMol m2).
Make sure that the fitting for the test lamp is fixed and not hangin by ropes.
A few millimeter to one side or the other makes a big difference in measuring.
Use a black room to do the test and dont stand to close.(everything reflects light)
Dont you need a ulbricht sphere to get the umol data??
You can measure Par=Photosynthetically active radiation with the quantum meter Par=(uMol m2).
Make sure that the fitting for the test lamp is fixed and not hangin by ropes.
A few millimeter to one side or the other makes a big difference in measuring.
Use a black room to do the test and dont stand to close.(everything reflects light)
To which measurement do you refer? Are you referring to radiance or irradiance? If you mean PPF (radiance) using an integrating sphere is common practice, but one could use a quantum sensor and place it very close to the lamp to find a ball-park PPF datum. A lamp emits equal radiance in all directions (or at least ideally it would) so a person can measure one spot with a quantum sensor to get close to the figure one would get with an ulbricht sphere working on the premise that light in all directions (except at ends of the lamp) would be the same intensity.
One could also use Knna's spreadsheet by digitizing the SPD (or getting raw SPD data from the manufacturer) and entering the total watts of lamp + ballast along with SPD data; to get PPF by math.
Using both knna's spreadsheet and a quantum sensor would provide better results becuase they could work as a check against each other.
A quantum sensor doesn't measure meter^2 by default; it's only like an inch in diameter; so it measures irradiance over its surface only. The reason the claim is made about meter^2, i.e., PPFD as umol/meter^2/second, is under the sun on a cloudless day, a person can take one measurement and assume all other measurements in a meter^2 will be the same; that isn't the case with lamps in a reflector. The footprint under artificial lights in a reflector isn't homogeneous like it is with the sun, so to find PPFD one would need to take at least 144 measurements (one every 3" length by width) and average them to find PPFD datum with lower error margin. For even greater accuracy one should take measurements every inch; LI-cor sells a 3' quantum sensor bar that basically averages the umol data over 3' with one quantum sensor to make life easier (but it's not cheap).
I plan on buying the Li-cor fluence quantum sensor (if the quantum response is sufficient) to find whole canopy umol datum called "Photosynthetic Photon Flux Fluence Rate" (PPFFR) or "Quantum Scalar Irradiance". Normal flat quantum sensor that are cosine correct measure photons over ~80 degree angle, they are good for measuring light falling downward but not for side lighting such as from reflective walls or off of leaves. Using PPFFR is good for measuring "whole canopy" irradiance as photon flux from all directions (granted the bottom-up irradiance is under-valued due to the base of the sensor). PPFD (or umol/X-area/second for density) only measures canopy irradiance as photon flux from photons falling downward at an defined degree angle.
Here is the quantum sensor I use, the Li-190 (~$460): http://www.licor.com/env/products/light/terrestrial.jsp
Here is the fluence quantum sensor I plan to by, the Li-193 (~$750): http://www.licor.com/env/products/light/underwater.jsp
I am going to ask a plant physiologist that works at Li-cor how he would setup a test with their quantum sensor to find ball-park PPF datum. I think I will plan to measure dead center under a lamp in a reflector that will be blacked out. I also plan on using knna's spreadsheet to find ball-park PPF (~+/-5% error margin) of the lamp with math; knna's spreadsheet can be used for any lamp as long as you have the digitized SPD (or raw SPD data) and total watts of ballast + reflector.
S
sm0k4
I love light talk. Yes, I think I was a bit too stoned while looking at the digilux charts. Seemed like the MH spectrum was on the HPS sheet. They still don't really tell you much about the bulb though. Just lumen output. It still takes a legit third party test to see if the output is really there in PPFD. But then again, more lumens usually translates to more PPFD.
I do look forward to reading about your work Spurr, do you have a blog or just post your works here?
I do look forward to reading about your work Spurr, do you have a blog or just post your works here?
Nope, no PhD, I just enjoy teaching myself the ins and outs of plant physiology and soil science/microbiology. I am working on getting my B.S. in plant science then I plan on getting a M.S. in plant physiology; maybe a doctorate or PhD after that but that's too far ahead to know what I want to do. Quantum mechanics is something I like to learn about due to its relevance to how plants use photons.
I do not have a blog, but that's not a bad idea
I was thinking about making a few threads as journals so they do not get lost in the sea of threads in this subforum.I am going to contact C.A.P. and ask for the raw SPD data from the spectroradiometer for the Digilux lamps.
FWIW i really like the Digilux lamps. I just got some for my 250w since i was getting noises from my Phillips lamp. The Digilux bulb was way cheaper and seems to be pretty good for digital ballasts. The lamps color is also a little different from the Phillips, it seems more red and less yellow(just my opinion)...
With a well designed light plan and the right equipment indoor lighting uniformity can be pretty accurate
. Whatever multiplier you take for your area, to compare it with other measurements you would still have to convert to umol/meter^2/second so what is the use of using "area"?look a few pages back I think you missed the point here. The philips GP 400 1000W EL is a double ended lamp. It has a small arc tube and is gas filled, it has no wire frame blocking the light. https://www.icmag.com/ic/showpost.php?p=4227664&postcount=53One reason I dislike those combo style lamps, e.g., 600w HPS + 400w MH, is they will not provide nearly as homogeneous SPD over the caonpy (e.g., due to reflective issues, diffuse vs direct photons) verses a single lamp like a 1,000w MH or 1,000w HPS. That and they have considerably lower radiance than a 1,000w HPS and even some 1,000w MH like Digilux lamps.
A remark about measuring PPF: Manufacturers always do that in a free hanging situation (in an ulbricht sphere). Output in a reflector may be higher due to the higher operating temperature. However, every reflector loses light so measuring reflected light is not a very accurate way to integrate total output. Our customers send us bulb to test in the ulbricht sphere to see if they need to be replaced. The sphere is calibrated to a standard so in principle all ulbricht sphere measurements should be about the same and comparable.
When we really dive into photons you might also want to take into account that it takes more energy to make blue photons, while only the photon count matters for photosynthesis. Recent studies have shown though that micromoles are a pretty accurate way to describe photosynthesis potential.
Spectrum diagrams from manufacturers are bollocks. They give you 400-700 nm, but not the high peak in infrared. You need to measure that yourself. knna can do those as well, he has a spectrum meter. Here is an example of an HPS spectrum diagram with the data that manufacturers normally don't show.
I think you are trying to find a very complicated and inaccurate solution for something that can be done easily in an ulbricht sphrere. Remember all manufacturer measurements are executed with naked lamps in spheres. You need the same test conditions to be able to compare or test. There is no simple way around that. If there would be one, we would be using that in the greenhouses. And for all measurements it's garbage in, garbage out.
@big ballin: I think you were getting noises from your ballast
some lamps resonate on certain frequencies. Ballast and lamp should be a matched pair, also in frequency. Most lamps (including the normal Philips GreenPower) are designed vor 50/60 hz, not for 35-70 kHz (the average electronic ballast operating frequency) and certainly not at 100 kHz+ (the professional electronic ballasts). That they last is due to the good construction.
There is nothing wrong with magnetic ballasts btw. They are reliable, sturdy and seldom fail. There is a lot wrong with the available average mains voltage, so electronic ballasts outperform magnetic ballasts. In lab tests where the voltage is optimal the electronic ballast wins only in power consumption and the ability to boost and dim (plus some safety features and optimal power adjustment to the lamp).
Just for the record: I got my best results with a combination of HPS and MH.
oh you gotta love technology eh?
Attachments
anybody using one of these?
Oldmac
Member
Looking thru the entire thread, I was surprised that nobody mentioned the Sun Pulse bulbs PSMH. They only work with electronic/digital ballasts and they come in various Kelvin temps; 3k, 4k, 6.4k, & 10k.
I've been using a couple of the 1000w bulbs over 4x4 aero/fog trays. I use 3k bulbs for most of flowering then switch to 10k for the last week. Production is similar to HPS but the finished product is better in terms of flavor, smell and even taste.
OM
I've been using a couple of the 1000w bulbs over 4x4 aero/fog trays. I use 3k bulbs for most of flowering then switch to 10k for the last week. Production is similar to HPS but the finished product is better in terms of flavor, smell and even taste.
OM
I use a 600/600 hps arrangement in my flowering room vertical. There aprox 24" from each other. There both Hortilux. I use those bulbs that have Kelvin ratings in my aquarium reef tank. I used 2 250w 10k. I dont think these are for Horticulture?
Oldmac
Member
The use of the 10k for the last week, is to turn the clear trichomes to cloudy and amber. Sort of a way to give the girls a little tanning action. I've used UVb supplemental lights to do that in the past, but the blue dominate light seems to be able to accomplish it also, and it's use is safer then the UVb.
OM
OM
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