desplegado
Member
Hello I'm a new grower and I just wondering ab light % what percent during each stage and height
Light %
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HandyGringo
Well-Known Member
You're going to have to provide more info than that. You can usually find the hanging height on the manufacturer's website.
Mumbeltypeg
Well-Known Member
Phototone app on your phone.. it’s close enough to get an idea of where you are.
ptrgrow
Member
dont use the apps they not work correct without adjusting...or not buy a lux meter...
which led you have?
i got 150 watt led 50cm away from plant with 25% 37,5 watt...in vegetative stge...
UnknownRemedy
Well-Known Member
People keep saying this but unless you're going maximum efficiency and CO2 this does not matter. The photonapp works good enough that you get the general idea of what your light is at.
desplegado
Member
It's not it's the vipar spectra xs1500 pro
desplegado
Member
Ok I didn't know if I needed a lux or par I've been searching
desplegado
Member
Vipar spectra xs1500pro
There starting flower there growing there pistils
desplegado
Member
I dont think my phone will work with it
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J2M3S
Well-Known Member
150 watts. It’s not much so stay close to the plant.
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coreywebster
Well-Known Member
109% at 16" distance
desplegado
Member
U mean 100% at 16 in? There just starting to grow there pistils
budman111
Well-Known Member
If you can afford a PAR meter that's even better
When I tested Korona (before it was renamed Photone), the diffuser was not needed for Android but, if you're using an iPhone and not using a diffuser, your results will be even more inaccurate. It's a function of how the sensor in the iPhone read light.
That's part of the email conversation that I had with their programmer in 2021 (I've been a software engineer for 30+ years, including a stint for Apple so I was interested in the app).
[time passes]
I haven't looked at the Photone web site in years but, checking just now, I see that they're selling a diffuser as an accessory. That makes me think that the people who write the software think a diffuser should be used.
[time passes]
From the "Support" page:
"If you're using an iPhone/iPad a diffuser is always required.
On Android devices (Samsung, Google, etc.) it depends on your specific model. Simply follow the instructions in the app and you won't go wrong"
One of the differences between a camera lens and a light meter is that camera lenses are designed to take light only from the area in front of the camera. In contrast, a lux/PAR meter is designed to capture the amount of light falling on the object where light is being measured because light strikes things from all sides. To provide accurate measurements, light/PAR meters have a parabolic cover. The diffuser for the iPhone helps improve accuracy of the readings in the same way the cover on the light/PAR meter does.
It depends on the model. I have an iPhone XSMax (don't laugh!). When I tested Photone against my blurple in 2021, it failed. When I tested it in 2022 against my Growcraft, it read 16% high.
What turned me off was the need for the diffuser. It's a work around for how the iPhone is designed. Now that they're selling a clip on diffuser, it's less of a kludge and, if it was more accurate, I could see its value.
To my way of thinking, for $32 I can get a Uni-T light meter that has an accuracy of 5%±, according to the manufacturer. That value can be plugged converted to PPFD, per the document I've written attached. Most of the data in the document is on the internet but there are a few values that I've determined by testing using my calibrated Apogee.
The bigger issue - what's the value of measuring light?
For historic purposes, it's really handy because it makes it easy to do what you did before. It also lets you know how well your grow is set up — if you can't get at least 800µmol on your grow, there's probably something that you should fix in your grow. But the bottom line is…
A light meter can tell you how much light is hitting your canopy but your plants will tell you how much light they can use.
Some grows max out at 500µmol. And those, two, grows had been watered improperly and parts of the soil were hyrophobic so that plants could not tolerate even 600µmol.
Other grows will handle more than the 800-1000µmol level that is commonly considered the light saturation point for mature cannabis. Should a grower stop increasing light levels once the meter reads, say, 900µmol? To my way of thinking, no. The number doesn't control how the plant react. If your plants are doing well at 1000, feed them more light because there's a direct relationship between DLI and crop yield and crop quality, up to the light saturation point (the light level above which a plant cannot process the incoming photons).
desplegado
Member
I have no idea what I'm reading here in the attachment
The stage of a cannabis plant is a handy guide but that's all. Cannabis i
The XS-1500 Pro will put out quite a bit of light and, at 16" hang height, you're at about 600µmol. I use word "about" because I don't have a PPFD map for that height so I'm looking at the one on the Amazon listing and the info here. 600 is considered the minimum amount of light that you should give a plant in flower. Why? Because.
That's the number that I think Bugbee provides and I know that DeBacco (You Tube) states that but DeBacco isn't a researcher. He repackages a lot of what Bugbee says but I haven't read anything of his that's not in synch with Bugbee and others.
An excellent source for this is from Bugbee student, Mitch Westmoreland, who published a couple of YT videos this Spring with some of the research that he did for his PhD. Every grower should watch at least one of his two videos. He lays out his research very well and it's pretty simple 0 give you plants at much light as they can tolerate with ambient temps up to the mid-80's. Do that through veg and into about the second week of flower. That will allow the plant to build out its infrastructure. Once you're in about week two of flower, if you want to maximize secondary metabolites, keep the temperature at the top of the flowers <=78°F.
OK, great info but it doesn't answer your question, because it depends on the grow. If you grow is "firing on all cylinders", you might be able to go to 100% and drop your hang height to 12". Per cocoforcannabis, that's going to get 950µmol± on your plant. That's quite a bit light but cannabis will handle more than that in ambient CO2.
On the other hand, you might drop the light to 14" and get canoeing of your leaves. If that's the case, you should check your grow and see what's not set up right. VPD could be off or not enough//too much wind in the tent or nutrient level too high. It could be a variety of things that, if they get adjusted, can allow you to feed your plants better.
Lux # PPFD
Lux is light measured I the green area of the graphic. It's what the human eye sees and lux meters aren't as sensitive to violet or deep red as PAR meters so there needs to be a way to convert LUX to PPFD.
Just like Photone does, you have to pick a conversion factor. For the Growcraft X3 flower light, the conversion factor is 0.016. For a light with a lot of blue in it, the conversion factor will be lower, a la 0.014 (going from memory).
The light model is on the left side of the table so scroll down the list until you find the XS-1500. As you move across the line for the XS-1500, the lux values in each column increase, 1000, 20000, etc (going from memory here). The PPFD values increase as the lux values increase.
[opens PDF]
For the XS-1500, when the light meter is giving a lux value of 10000, the PPFD is 145µmol. If your lux meter is reading 40000lux, that means that the PPFD value is 580µmol. And at 70000 PPFD is 1015µmol.
The 0.015 factor is the "standard" conversion factor that was being kicked around (I think I heard that on Migro back then) and it's fairly accurate.
A light that has a lot of red, like the Growcraft flower light and the HLG R spec lights, have a high conversion factor.
For your light, though, just used XS-1500 row and it's going to be close enough.
Again, this will get you in the ballpark because the purpose of the meter is to tell you how much light is hitting the canopy but only the plants can tell you how much light they can use.
HTH.
[edit]
I bought an Apogee when I couldn't get Photone working. A lux meter is, in practical terms, as accurate as an Apogee.
desplegado
Member
Is ppfd next to the names and the lux it is or somewhat the top like the 10,000?