zeke99
Active member
I got ya now.
Yes I have a basic understanding of photons and that we're talking about the human eye (footcandles) vs the plant.
passive plant killer
- Thread starter delta9nxs
- Start date
I got ya now.
zeke99
Active member
http://www.apogeeinstruments.com/conversions/footcandles-ppf.html
Here are some conversion numbers from Apogee.
Going by these numbers and if this meter isn't completely whacked out of the package, I'd need to get the plants mere inches away to approach 10-12k footcandles.
The device measures up to 5000 footcandles. With my 1k MH bulb, that's about 10" away. With the 1k HPS (ushio) it's 16".... The stacked double 600w appears to be much stronger than the single 1k and the bulbs are older.
Here are some conversion numbers from Apogee.
Going by these numbers and if this meter isn't completely whacked out of the package, I'd need to get the plants mere inches away to approach 10-12k footcandles.
The device measures up to 5000 footcandles. With my 1k MH bulb, that's about 10" away. With the 1k HPS (ushio) it's 16".... The stacked double 600w appears to be much stronger than the single 1k and the bulbs are older.
a foot candle is 10.76 lux. both measure the same thing the same way just use different scales. neither converts directly to umols.
for your purpose, which is determining distance from the light, there are approx 54 lux per umol. or 5.02 f.c. whichever way your meter reports.
be careful with that bare mh. those sumbiches are hot! i don't know if you have noticed but i run a big fan turned horizontally right under the light. blowing heated air up past the plants.
looks like the meter doesn't read high enough to reach 1500 umols. my quantum meter reads 2000 umols which is equivalent to approx 10,000 f.c. you need to read at least 7,500 f.c.
zeke99
Active member
yeah I'm just going to return this thing....
There may be three turtles turning over in their graves.
For all the right reasons.
Much.
Love.
For all the right reasons.
Much.
Love.
I don't fully understand how plants use different frequencies, but I think it is a little intuitive to consider a plant is green therefore reflects green, if your meter is based on the human eye adjusted area of the freq you will be measuring that green light as lux or lumens, or whatever. This is radiation that is not in the PAR (photosynthetically active radiation) range.
so the theory goes, I'm not sure I'f what I just typed is all the readable
zeke99
Active member
Plants use green light. But I returned the thing anyways. It was interesting to poke around with for a few minutes, that's about it. Soon enough I'll have $200 for the quantum meter. One thing that did work out from the trip to the store is the laser pointer style thermometer. So I'm going around the circles now and making sure no leaf is over 78-79 degrees. I'm starting to get my confidence back after a couple of absolute failures.
http://www.actionbioscience.org/education/hershey.html?print
Avoid Misconceptions When Teaching About Plants
David R. Hershey
A widespread misconception states that leaves reflect all green light and do not use green light in photosynthesis. Leaves often absorb more than 50% of the green light and use it efficiently in photosynthesis.8,22 The origin of this misconception is probably the chlorophyll absorption spectrum in textbooks. The chlorophyll absorption spectrum is a graph of light absorption versus light color. It shows that chlorophyll absorbs much red and blue light but little green light. However, accessory pigments absorb green light and pass that energy on to chlorophyll.
David R. Hershey
A widespread misconception states that leaves reflect all green light and do not use green light in photosynthesis. Leaves often absorb more than 50% of the green light and use it efficiently in photosynthesis.8,22 The origin of this misconception is probably the chlorophyll absorption spectrum in textbooks. The chlorophyll absorption spectrum is a graph of light absorption versus light color. It shows that chlorophyll absorbs much red and blue light but little green light. However, accessory pigments absorb green light and pass that energy on to chlorophyll.
zeke,
Let me make sure I am understanding you.
are you claiming that plants use green light as a *significant* source of energy to power their photosynthesis? This is a large claim and will require more evidence than just posting a link to a site where someone says this is so.
When you say plants use green light, what is the wavelength you are speaking of? some of the area we see as green is not absorbed at all by the plants, but rather reflected, this is the part the plants don't use
say for arguments sake we say they do use some, they don't use the part you see reflecting. (Do we agree on this?)
Why do you think plants look green to your eye? They are reflecting that part of the frequency which we see as green or as a shade of green. Sure there are difference shades and the plant may use some areas around green to do something, but my point is they don't use the light the same as say blue.
as for the the link you posted? I can't find any supporting documents for their claim. Maybe, I didn't see them. Are there any studies published that back this up?
I'm not saying this is right and your source is wrong, I'm just saying, without knowing how these people came to their claim, we can't really evaluate how accurate their claims are. My link contradicts your link. Maybe they are too general, but my point is if they contradict, at least one of them is wrong. If we can't read the a study we have no way to know how much credibitliy the claim warrants. All we can do is choose to believe. I advise against this, obviously.
Here is something that claims plants don't. I am not using this as a source, because it is self lacks any explanation of how the study was done. I'm just showing you there are other opinions about green light than the one you posted.
http://bioenergy.asu.edu/photosyn/education/photointro.html
Energy for this process is provided by light, which is absorbed by pigments (primarily chlorophylls and carotenoids). Chlorophylls absorb blue and red light and carotenoids absorb blue-green light (Figure 2), but green and yellow light are not effectively absorbed by photosynthetic pigments in plants; therefore, light of these colors is either reflected by leaves or passes through the leaves. This is why plants are green.
-------
Let me make sure I am understanding you.
are you claiming that plants use green light as a *significant* source of energy to power their photosynthesis? This is a large claim and will require more evidence than just posting a link to a site where someone says this is so.
When you say plants use green light, what is the wavelength you are speaking of? some of the area we see as green is not absorbed at all by the plants, but rather reflected, this is the part the plants don't use
say for arguments sake we say they do use some, they don't use the part you see reflecting. (Do we agree on this?)
Why do you think plants look green to your eye? They are reflecting that part of the frequency which we see as green or as a shade of green. Sure there are difference shades and the plant may use some areas around green to do something, but my point is they don't use the light the same as say blue.
as for the the link you posted? I can't find any supporting documents for their claim. Maybe, I didn't see them. Are there any studies published that back this up?
I'm not saying this is right and your source is wrong, I'm just saying, without knowing how these people came to their claim, we can't really evaluate how accurate their claims are. My link contradicts your link. Maybe they are too general, but my point is if they contradict, at least one of them is wrong. If we can't read the a study we have no way to know how much credibitliy the claim warrants. All we can do is choose to believe. I advise against this, obviously.
Here is something that claims plants don't. I am not using this as a source, because it is self lacks any explanation of how the study was done. I'm just showing you there are other opinions about green light than the one you posted.
http://bioenergy.asu.edu/photosyn/education/photointro.html
Energy for this process is provided by light, which is absorbed by pigments (primarily chlorophylls and carotenoids). Chlorophylls absorb blue and red light and carotenoids absorb blue-green light (Figure 2), but green and yellow light are not effectively absorbed by photosynthetic pigments in plants; therefore, light of these colors is either reflected by leaves or passes through the leaves. This is why plants are green.
-------
zeke99
Active member
No, I'm saying it's a debunked myth that higher plants (including ours) reflect all and don't use any green light for the photosynthetic process.
Take a look at all of the links posted to this thread:
https://www.icmag.com/ic/showthread.php?t=147095
daggerinmyback
Member
I'll catch back up (currently on page 135) Been busy side by side by side comparing my tiny PPK setup to my friends grows with cuts all taken and rooted at same time also transplanted same day and I'm just using straight cheap coco brick, no rice or perlite, they also used more lighting compared to my meager 1600w, one used 4000w from vert different corners and another did 2400w with 600's ... I used less money on everything from nutes to media to lights, bills and water *(buying it gallon by gallon as I have no machine yet) same number of plants yielded me enough I went in to de-leaf the last one tonight for chop tomorrow and I'm already ahead in wet weight by about 9oz's and I still have one last baby to chop, sad day when the one with the least can leave and go on a vacation or 3 for 5 days each and then stay gone 2 weeks while the other 2 slaved away... I also spent maybe an hour a week defoliating and training the first three weeks which was veg, after that I was gone and only topped it off adding up to about 1 hour every two weeks due to combining Verdantgreens Mod Scrog with PPK but letting it overgrow a bit (they rapidly shot up I couldnt keep track) then we all flipped the same day, mind you I have never ran these genetics and neither had 1 friend (that was a control of sorts, they also had 4000w and added CO2 and a/c etc and sealed already built dedicated grow room) other person grows this cut like a religon (its fully ready to chop after about 46 days without CO2 addition and 42-43 with it, best thing ever brought back from iraq besides living troops was these beans) im 9oz's ahead of the 2nd place person who always grows this cut and 11 oz's ahead of the one with the most lights and dedicated grow room, I still have the one to cut and weigh wet but I cant thank D9 enough for helping my lazy ass crop out a full 6 plants while I was traveling all over and nowhere near my house lol
they were feeding at least 2200ppm and dedicated guy was putting in 2550ppm my low dose jacks made his look like midgets in two weeks ... also I started kinda flushing mine out with half mix and half RO the last 4 days just for safety as I know the cheap retains a lot more due to lack of 35% cation exchange rating thingy (I think thats what it was called) and I got a few (less than 12 leaves per plant) showed lack of nutes but they matured faster that way (trichome under eye loupe test-wise)
been busy... now what to do with all these flowers....
they were feeding at least 2200ppm and dedicated guy was putting in 2550ppm my low dose jacks made his look like midgets in two weeks ... also I started kinda flushing mine out with half mix and half RO the last 4 days just for safety as I know the cheap retains a lot more due to lack of 35% cation exchange rating thingy (I think thats what it was called) and I got a few (less than 12 leaves per plant) showed lack of nutes but they matured faster that way (trichome under eye loupe test-wise)
been busy... now what to do with all these flowers....
from a link in the thread:
"The green light we can see is not/cannot be absorbed by the plant, and thus cannot be used to do photosynthesis."
this is my point, I was simply trying to explain why measuring luxe isn't a good metric for how much your light is putting out for the plants
Do we agree that plants reflect green and the photons reflected don't contribute to photosyn?
If you agree, then you can see why a meter that measures PAR is beneficial. I'm not saying better, it just measures something else. There is still a lot to learn about nature, but there is a lot of research to show that green isn't something you should focus on with spectrum for plant growth and therefore shoal be factored out of your measurements, hence PAR meters...
This was done in 1994 and is a little outdated but still largely pertinent, especially figures 2 and 3 showing percentages of light and yields. Subsequent studies have altered the percentages slightly.
http://biology.mcgill.ca/Phytotron/LightWkshp1994/1.4 Prikupets/Prikupets text.htm
http://biology.mcgill.ca/Phytotron/LightWkshp1994/Contents.htm
editing to add the contents page from the workshop. it is a goldmine.
these graphs are not part of the study above, but are interesting, just thought you guys might like to see them. They show green is capable of driving some photosynthesis but not nearly as much as the other pigments. The newer studies are finding white to be a much larger contributor than previously thought. I can't find the links right now but i'll keep looking.
i show the hortilux that i use as i have used a lot of different bulbs over the years and nothing grows weed like these things.
http://biology.mcgill.ca/Phytotron/LightWkshp1994/1.4 Prikupets/Prikupets text.htm
http://biology.mcgill.ca/Phytotron/LightWkshp1994/Contents.htm
editing to add the contents page from the workshop. it is a goldmine.
these graphs are not part of the study above, but are interesting, just thought you guys might like to see them. They show green is capable of driving some photosynthesis but not nearly as much as the other pigments. The newer studies are finding white to be a much larger contributor than previously thought. I can't find the links right now but i'll keep looking.
i show the hortilux that i use as i have used a lot of different bulbs over the years and nothing grows weed like these things.
Last edited:
Turtles = turtles man.
You know.
Reptiles.
Shell.
The whole deal.
You know.
Reptiles.
Shell.
The whole deal.
i'll try to get some pics up later. i now have the g13, og nukush, and rene x nuken in ppk's in veg as well as one swt #4.
the g13 goes into flower on the 25th.
both the og nukush and the rene x nuken showed pistils strongly in veg.
the purple nukush and the kish x juicy fruit are probably male. i've got clones almost rooted enough to test them for sex.
pics of all later.
