Homer's Legal 4-Plant Max Perpetual Minimalist Garden In Ontario

Whenever I mention that I used my 40-year-old photographic light meter to try to determine how much light my plants are getting I get told that it is completely useless when it comes to plants because you need a PAR meter.

Apparently a PAR meter stands for, Photosynthetically active radiation, which means it is only reading the part of the light spectrum that the plants use for photosynthesis and that range is between 400 and 700 nm wavelength of light.

And my light meter apparently reads in lumens which is the intensity of light in the visible spectrum to humans which is the, wait for it, 380-780 nm range. And yes Par is the amount of light hitting an object and lumens is intensity but they are measuring the almost identical part of the spectrum because plants use almost the same spectrum for photosynthesis as we do for sight.

Since it isn't an exact pairing 400 to 700 versus 380 to 780 there would possibly be a few percentages of error using this method but to say it isn't a practical alternative is ridiculous. So my conclusion is to start using your light meters for your plants because it's measuring almost the same thing as a par meter.

The reason I bring all this out is I saw a really interesting video on Mr. S's journal. The Sauga Ends Here

I highly suggest checking it out because I found it very interesting about the relationship between light intensity and bud production. Using my light meter today I figure at 24 inches and 200 W my plant is getting 1/8th the intensity of light as it would in direct sunlight and after watching these videos I think I might try bumping that up a little more. I ran into problems last time because I bumped it up too high but according to this guy, cannabis is a sunshine loving plant where more light equals more buds.

I'm not going to go crazy but I'd like to be a little higher than 1/8th. I'm going to look for more of this guy's video; he seems pretty well informed.

Edit: I just used my light meter with my MegaLight and at full power, almost 650 W, at 2 feet (which is the maximum setting and distance recommended) I had one half the illumination of direct sunlight.
 
Pennywise said:
Whatever you use is great for comparisons.
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I suspect @InTheShed may disagree with my conclusions about my meter and unfortunately, more often than not he is right. :oops:

But yeah, I figured out a while ago I think I was at about 1/8 direct sunlight intensity where my Mega Light is set and now that I know after researching today that my meter is probably right in telling me that and watching that video of that guy that seemed like a real expert saying light intensity is directly proportional to bud production I think I might try bumping them up a bit, bit by bit.

Went for a drive to warm up my engine so I could change my oil. Nice to get out.
 
Homer Simpson said:
cannabis is a sunshine loving plant where more light equals more buds.
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I don't recommend using sunshine as a gauge against which to judge your indoor grow. No one is (or should be) hitting their plants with 130,000+ lux indoors.
 
InTheShed said:
I don't recommend using sunshine as a gauge against which to judge your indoor grow. No one is (or should be) hitting their plants with 130,000+ lux indoors.
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According to the fellow in the video who is working with PhD's at Utah State University there is a decreasing return the higher you go but generally more light equals more buds. My MegaLight at full blast at the closest distance they recommend is one-half sunlight intensity and according to this fella, I think that's about where it stops being practical to go higher with artificial light and I am at 1/8 sunlight so although I would not recommend 130,000 lux I think it's pretty reasonable for me to increase it some.
 
Keep in mind the guy works for a light manufacturer!

Here is the Royal Queen Seeds lux recommendation if it's of any help:

"HOW MUCH LIGHT DO YOUR CANNABIS PLANTS REQUIRE?
  • Clones and seedlings: 5,000–7,000 lux
  • Vegetative growth: 15,000–50,000 lux
  • Flowering: 45,000–65,000 lux
  • Maximum recommended amount of light: 75,000 lux

What about even more light? At some point, increasing the light beyond a threshold plant can manage will actually diminish returns. Said differently, once you reach about 85,000 lux, it’s simply too much. Some strains may already show signs of light stress at only 75,000 lux, with the risk of light bleaching increasing at over 80,000 lux. To keep it safe, it is best to stay at or below 75,000 lux."
 
InTheShed said:
Keep in mind the guy works for a light manufacturer!

Here is the Royal Queen Seeds lux recommendation if it's of any help:

"HOW MUCH LIGHT DO YOUR CANNABIS PLANTS REQUIRE?
  • Clones and seedlings: 5,000–7,000 lux
  • Vegetative growth: 15,000–50,000 lux
  • Flowering: 45,000–65,000 lux
  • Maximum recommended amount of light: 75,000 lux

What about even more light? At some point, increasing the light beyond a threshold plant can manage will actually diminish returns. Said differently, once you reach about 85,000 lux, it’s simply too much. Some strains may already show signs of light stress at only 75,000 lux, with the risk of light bleaching increasing at over 80,000 lux. To keep it safe, it is best to stay at or below 75,000 lux."
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Thank you, Shed. That was exactly what I needed. I do admire how organized and helpful you are with your archives at your fingertips at a moment's notice with pertinent info. The Jay Peterman, of the cannabis world. :) "Quickly Elaine, to my archives!!

According to my meter, I read about 175,000 lux today outside in the sunlight. As you noted today outside in sunlight is 130,000+ lux so I think my meter needs to be calibrated. I have a screw head in the back to adjust it so I may. My reading was 44,000 lx where my light is set at 200 W and 24 inches where my plants are at. If I adjust for error and make my one 175,000 lx reading 130,000 lx then my 44,000 lx becomes 33,846 lx.

That is well below the recommended 45,000 to 65,000 lx for flowering. I would like to be at least 45,000 lx. Won't take a lot of power; that Mega Light is a beast. I don't know if it's linear but with my 200 W giving me about 33,000 lx to get the maximum amount of lx for flowering at 24 inches with this light I would need about 400 W which leaves this thing with 250 W to spare.

Good point about his job/conflict of interest. But still, he did have a lot of info apparently derived from real pro experimentation. But who knows what is real anymore. :goof:
 
I found it interesting that he asserts that their research shows that red and blue lights don't change bud production instead they change stem length. I have always thought it would be better to have lights more in the red spectrum because they induce budding but he says it doesn't do anything but make a plant longer and since height can be an issue in my basement any new lights I ever get I will try to get cooler lights to keep my plants shorter if it doesn't cost me anything in bud.
 
Pennywise said:
I always wondered about that.
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Yea, he had a few good tidbits. I had read total darkness at night is vital and he affirmed it. I guess what value to give that is up to the viewer but he seems pretty smart and informed to me. But all is relative. :oops:
 
I didn't watch either of the videos all the way through, but he definitely seemed to know what he was talking about.
 
Aside from being the founder of Apogee Instruments, he is a Professor at Utah State heading the research into hemp and cannabis. His light company was started to develop and provide tools they needed in their research.

I don’t believe that Apogee is anything more to him than a side project and tool for his research, if you go to the Apogee website, they have pages of free information and give you conversion factors that allow you to do approximate conversions from LUX to ppfd so you can use a cheap light meter to figure out what your plants are getting.

I did a break down of the calculations, and light map, of my lights early on in my journal. If you are running 3000K lights, the conversion factor I used will work for you, if you are using other spectrums, they have a list.
 
The Celt said:
Aside from being the founder of Apogee Instruments, he is a Professor at Utah State heading the research into hemp and cannabis. His light company was started to develop and provide tools they needed in their research.

I don’t believe that Apogee is anything more to him than a side project and tool for his research, if you go to the Apogee website, they have pages of free information and give you conversion factors that allow you to do approximate conversions from LUX to ppfd so you can use a cheap light meter to figure out what your plants are getting.

I did a break down of the calculations, and light map, of my lights early on in my journal. If you are running 3000K lights, the conversion factor I used will work for you, if you are using other spectrums, they have a list.
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Thanks, Celt for clarifying his background. I got a lot out of those vids. Good job.
 
The Celt said:
He‘s got a whole series of them, some can be found at Apogee’s site, but most are actually videos of lectures at the university
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Oh cool. I was hoping he would have more but hadn't gotten around to looking for them. I will look for them, thanks.
 
I found this video very informative. From his parameters, I think the only things I really need to improve is perhaps to add some silica and besides that a little more light intensity. He suggests light intensity should be anywhere from one half that of direct sunlight up to really pushing it three quarters.

From my experiments with my light meter, I think I am at about 1/6th the intensity of direct sunlight. I don't see the point of giving it the full 50% suggested because my yields are pretty good but I think I'd like to be up around 25% range.

I admire this guy because it took me quite a while to figure out if he has a Ph.D. because he just uses his name but it ends up he does have a doctorate. He seems very down to earth.


He mentions oxygen for the roots and I have been wondering about this for a while. I know from my brewing in the initial stages yeast loves lots of oxygen because when I would oxygenate my water with an aquarium filter that I brewed with I would get about a 50% reduction in the fermenting time the yeast loved it so much. So I have been thinking of oxygenating my water.
 
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