blue will give more compact and vigurous growth, even if HPS gives more lumens. you can control the plant better with blue. i come to think that blue is good during flowering too, somewhere around 3:1 ratio. this will produce fatter buds rather than streched out on the stem. am i right?
Making a bud look delicious
- Thread starter Mr.I
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alright here's another question, how much photons is maximum for the specific spectrums of light? 10000 lumens is so called "maximum" in HID, cfls fluorecsent terms.
LEDs work differently, in order to measure effectiveness of LEDs you have to measure the photons given to the plant. now, there are few chlorophylls known that utilize different spectrums and produce carbohydrates for photosynthesis: chlorophyll a, b, c, d... carrotenoids.. etc. "a" and "b" are the two major ones, and there are 3:1 ratio of chlorophyll "a" to "b".
from knowing this information, how the hell would i measure the maximum absorption rate for a specific spectrum without wasting more energy?
if in general lighting we would think that its 10000 lumens, and lots of light is wasted, then how much % is used and in what spectrums?
born2killspam
Well-Known Member
As far as pure photosynthetic productivity goes, no you're wrong.. An HPS will provide more photons, and the average photon will also have a higher absorption efficiency.. So more photosynthetic reactions will happen under an HPS, thus more energy to build plant material is converted..
When photons with higher than required energy to reduce chlorophylls strikes a leaf, the chorophyll will absorb only the needed energy to undergo its reaction, and the rest will be re-emmited from the molecule as a lower energy photon (a process called fluorescence).. Chlorophyll is designed to reabsorb anything it can, but these new photons will often be too low in energy to be useful to chlorophyll, and will be absorbed as heat etc..
So production wise its definately best to spend your energy creating more photons that have just enough energy to get the job done..
That being said, there are definately further complexities regarding 'how' a plant grows under different lights, and I'm a huge proponent of MH in the flowering chamber.. I started with a single HPS, then came across a really good deal on some MH's, so I tossed them in and expanded my area.. That crop was great.. My next crop I had enough HPS, so the MH came out, and I was using all Hortilux Enhanced bulbs..
The yield was definately better, but I had also learned quite a bit about training.. But the quality was lower.. Flavors didn't pop as much and the crystals weren't as dense..
Both crops were the same genetics, the same hydro system/nutes, and both went very smoothly and healthily..
Pegging the light as the only variable, the next crop I went back to the MH with the $17 GE bulb with the HPS like before, and was treated to the same quality as the first.. Buds closer to MH than HPS tend to be slightly less dense, but more enjoyable..
When photons with higher than required energy to reduce chlorophylls strikes a leaf, the chorophyll will absorb only the needed energy to undergo its reaction, and the rest will be re-emmited from the molecule as a lower energy photon (a process called fluorescence).. Chlorophyll is designed to reabsorb anything it can, but these new photons will often be too low in energy to be useful to chlorophyll, and will be absorbed as heat etc..
So production wise its definately best to spend your energy creating more photons that have just enough energy to get the job done..
That being said, there are definately further complexities regarding 'how' a plant grows under different lights, and I'm a huge proponent of MH in the flowering chamber.. I started with a single HPS, then came across a really good deal on some MH's, so I tossed them in and expanded my area.. That crop was great.. My next crop I had enough HPS, so the MH came out, and I was using all Hortilux Enhanced bulbs..
The yield was definately better, but I had also learned quite a bit about training.. But the quality was lower.. Flavors didn't pop as much and the crystals weren't as dense..
Both crops were the same genetics, the same hydro system/nutes, and both went very smoothly and healthily..
Pegging the light as the only variable, the next crop I went back to the MH with the $17 GE bulb with the HPS like before, and was treated to the same quality as the first.. Buds closer to MH than HPS tend to be slightly less dense, but more enjoyable..
born2killspam
Well-Known Member
Regarding your other question, I don't know exactly where maximums lie.. The sources I found the information were broadly scoped and said that limits would vary largely species to species, location to location..
With cannabis, not much benefit is seen beyond 50-60W of HPS per sqft.. If you assume an average wavelength of say 630nm (and ideal efficiency) for an HPS then 50W works out to ~4.7*10^28 photons.. Actually that exponent will generally be the same regardless of the light color, but efficiency is far from 100% so I'd guestimate 3*10^28 photons/sqft/s to be the usable maximum for cannabis..
All light is the same though.. Watts are just as effective for LED.. With LED though you need to remember that they are monochromatic so its crucial that their wavelength be in a high absorbance band otherwise you'll need to multiply the watts by a puny absorbtion factor..
Also remember that the various pigments are all available to accept photons, and that most have absorbtion peaks in both red band and blue band (but its more efficient to excite them with red band photons).. The one big odd man out is B-carotene.. It pretty much absorbs nothing redder than 550nm..
With cannabis, not much benefit is seen beyond 50-60W of HPS per sqft.. If you assume an average wavelength of say 630nm (and ideal efficiency) for an HPS then 50W works out to ~4.7*10^28 photons.. Actually that exponent will generally be the same regardless of the light color, but efficiency is far from 100% so I'd guestimate 3*10^28 photons/sqft/s to be the usable maximum for cannabis..
All light is the same though.. Watts are just as effective for LED.. With LED though you need to remember that they are monochromatic so its crucial that their wavelength be in a high absorbance band otherwise you'll need to multiply the watts by a puny absorbtion factor..
Also remember that the various pigments are all available to accept photons, and that most have absorbtion peaks in both red band and blue band (but its more efficient to excite them with red band photons).. The one big odd man out is B-carotene.. It pretty much absorbs nothing redder than 550nm..
550 is green color my friend. b-carotene would absorb maximum of 2-5%, but green light still gets absorbed.
and 630 has chlorophyll absorption rate of around 20-30%, 662nm 80% and believe or not in blue spectrums it sky rockets more than 90%. so you see its not only about the wavelengths, and chlorophyll peaks of spectrums, its also about the specific absorption rate i'm talking about. so, it does not mean necessarily that having all red will give you better faster growth, though you are right that red photons travel further per unit of energy, but the blue carry more energy with them. so if i have same amount of photons in blue and red, which one you think will do better?
so having all red, does not necessarily mean the highest rate of photosynthesis.
born2killspam
Well-Known Member
I meant the cutoff for B-carotene is about 550nm.. It absorbs well at shorter wavelengths than that..
Also, many transitions resulting from blue band photons will push electrons up more than one level.. This second level is useless to chlorophylls, its incredibly unstable, and the energy released when it drops will be wasted as heat.. Every now and then one of those high energy electrons will participate in a rather undesirable reaction..
The absorption spectrum plots 'energy' on the Y-axis, not number of photons, so each blue photon will depict more energy on the graph than each red photon, but to the process of photosynthesis, there is NO difference between a red and a blue as long as both have 'enough' energy.. Any excess energy in a photon is fluoresced, and likely wasted as internal heat..
Remember I'm talking about pure photosynthetic power though, and ignoring the complexities, because like I said, I'm a huge fan of MH..
Imagine you need to hire ppl to carry small boxes one at a time.. Its not beneficial to pay more for stronger workers if weaker ones can do the same job..
About the red travelling further, light does not work like that exactly.. Red light is more penetrating to atmosphere.. Blue is easily scattered (why the sky is blue).. When the sun is low in the sky, rays need to travel through more atmosphere, and the blue gets scattered long before the red, so the sky looks red..
In summary, photon absorbtion rate will be higher in the red band, while the energy absorbtion rate (as depicted in the spectra) may peak in the blue range, but the re-emmitted/wasted energy in the blue band will be higher than in red..
Its kind of like when somebody opts to buy a large soft-drink when they're just going to take a few sips and throw it away.. Same job could be done with a small..
Also, many transitions resulting from blue band photons will push electrons up more than one level.. This second level is useless to chlorophylls, its incredibly unstable, and the energy released when it drops will be wasted as heat.. Every now and then one of those high energy electrons will participate in a rather undesirable reaction..
The absorption spectrum plots 'energy' on the Y-axis, not number of photons, so each blue photon will depict more energy on the graph than each red photon, but to the process of photosynthesis, there is NO difference between a red and a blue as long as both have 'enough' energy.. Any excess energy in a photon is fluoresced, and likely wasted as internal heat..
Remember I'm talking about pure photosynthetic power though, and ignoring the complexities, because like I said, I'm a huge fan of MH..
Imagine you need to hire ppl to carry small boxes one at a time.. Its not beneficial to pay more for stronger workers if weaker ones can do the same job..
About the red travelling further, light does not work like that exactly.. Red light is more penetrating to atmosphere.. Blue is easily scattered (why the sky is blue).. When the sun is low in the sky, rays need to travel through more atmosphere, and the blue gets scattered long before the red, so the sky looks red..
In summary, photon absorbtion rate will be higher in the red band, while the energy absorbtion rate (as depicted in the spectra) may peak in the blue range, but the re-emmitted/wasted energy in the blue band will be higher than in red..
Its kind of like when somebody opts to buy a large soft-drink when they're just going to take a few sips and throw it away.. Same job could be done with a small..
alright which 175W metal halide would be the best, i need it for clones. i've got these fluorecents in there right now and i don't like it. i want the clones to grow more compact than they are right now. is there 20000K 175W metal halide and how many lumens would itemit? small cabinet 2 feet by 2 feet and 1 1/2 feet height. will install it in a cooltube to protect the babies.
searched the net, i find many with different readings from 4000K to 14000K and doesn't say lumens. but which one in your opinion would be the best?
searched the net, i find many with different readings from 4000K to 14000K and doesn't say lumens. but which one in your opinion would be the best?
found two websites
ballast: http://www.bulbs.com/Metal_Halide-High_Intensity_Discharge_(HID)_Ballasts-Ballasts-Category/results.aspx
bulb: http://www.lightbulbsdirect.com/page/001/PROD/MetalHalide/MH175U-USA
would these two work together?
ballast: http://www.bulbs.com/Metal_Halide-High_Intensity_Discharge_(HID)_Ballasts-Ballasts-Category/results.aspx
bulb: http://www.lightbulbsdirect.com/page/001/PROD/MetalHalide/MH175U-USA
would these two work together?
born2killspam
Well-Known Member
The higher the K, the less red will be in there.. 20000K is really high..
Lumens mean dick to plants.. Lumens are measured in terms of the absorbtion spectrum of the human, not plants, and our peak lies right at 550nm where plants don't absorb well.. Lumens are only relevent to photosynthesis is you're comparing two lights with the same K rating..
The lower the K rating the lower then energy of the average photon, so you will get more photosynthetic power from 175W of lower K..
A 175W is 'sufficient' for that area, but the height will be a problem.. MH bulbs are big unless you hunt out special ones.. A 175W bulb has a 4" diameter, and it has to stay atleast 8" maybe from the plants..
Aquarium shops may have tubular bulbs, but honestly I don't even think you could pull it off in that area with one of these stadium style..
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=13949
Lumens mean dick to plants.. Lumens are measured in terms of the absorbtion spectrum of the human, not plants, and our peak lies right at 550nm where plants don't absorb well.. Lumens are only relevent to photosynthesis is you're comparing two lights with the same K rating..
The lower the K rating the lower then energy of the average photon, so you will get more photosynthetic power from 175W of lower K..
A 175W is 'sufficient' for that area, but the height will be a problem.. MH bulbs are big unless you hunt out special ones.. A 175W bulb has a 4" diameter, and it has to stay atleast 8" maybe from the plants..
Aquarium shops may have tubular bulbs, but honestly I don't even think you could pull it off in that area with one of these stadium style..
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=13949
How about this puppy
http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+3733+8074+13946&pcatid=13946
seems like not that big.
which one is smaller? and the ballast for the first one, its a special ballast, or i can connect just the regular one somehow?
born2killspam
Well-Known Member
Cool tubed maybe, if you're a master µgrower.. I wouldn't attempt it if I had anything to lose..
ok i'll take your advice for it.
how small is the area? and how do you cope with heat? something like cool tube or just really good ventilation?
my main idea to veg my clones so they are as compact as they can be. right before that i used flowering area that i use now for flowering as veg, with blue fluorrescents of coarse, and it worked really good. my internodes were half an inch, so i was thinking to do the same in enclosed area for my clones which are in space 2by3 by one and a half feet
why is it important to keep your plants 8 inches away from the light? is it only because of heat? because i could make the cool tube for the bulb myself and attach a vent straight to it to make sure really good ventilation. would this work for such a small space?
born2killspam
Well-Known Member
Forget the double arc.. I'd be very impressed if you could work out a single arc in 6cuft.. And yea, if you get the tops too close, they'll shrivel up.. Its your height thats an issue.. 4sqft is appropriate for 175-250W I suppose, but 18" would be tough to work out with a cfl, let alone HID.. Figure minimum 6" for growing medium, and 12" for the plants if you flip them to 12/12 without any vegging at all, AND get really lucky.. Thats your 18" used up already..
sounds good. here's just an update.. this is 5 weeks. and they look kind of ready.. but i know thats misconseption probably.
could it be that some buds on the plant are ready and some are not?
like i got a few buds that have mostly red hairs on the same plant where the other main bud has only 20%red hairs? can i snip it? or i could still leave it on and it would get bigger?
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thats true. i got 2 and a half feet in flowering. minus the pot which is 10 inches. tight spaces. really tght. i still would like to veg them for a week or two, as its been said it will give me much more yield and i see that its true. i want to veg as compact as possible, thus concentrating tons of light in there. i veged my flowering girls for three weeks prior flowering and they already had flowers forming in veg, when i set them to 12/12 they exploded. they were about 11 internodes and only about 8 inches high. they making out great.
