Anyone have any luck with these? This is my first grow and I don’t want to get a par meter quite yet. I got a reading of 32,000 lux , 800 ppfd, and 51.6 DLI. I have no idea if this is good and if anyone knows how accurate it could possibly be. I’m growing in a 3x3 tent with a 900 watt viparspectre full spectrum led
Tag @dbrn32,he’s the light expert here.Anything about lights he’s your authority. Good luck!
@dbrn32 , had a question about an app ppfd meter
Thank you. @Weedlover1
You got me wondering… I purchased an app for my iPhone called Korona. You pay $5 for each type of light you want to measure, full spectrum LED, burples, HPS, MH, etc. I never trusted it.
I recently had a concern in one of my grows caused by the light and got frustrated enough to buy an Apogee Quantum 500 par meter.
Above is the readings I got from both devices under an HLG 320 kit.
I just downloaded ppfd meter app today and gave it a try. I may invest in a par meter after this grow but if someone could show it works on the app I downloaded or another one, that would save a lot of money. But it is doubtful that an app could be that accurate. @CMichGrower
LOL, it’s not even close. Yeah I love my apogee quantum meter, know exactly whats hitting the plants.
Anyone ever tried any other accurate par meters that aren’t 500 dollars
I tried two of them and they weren’t really consistent with lux meter. Wasn’t a super high end calibrated lux meter though. Also found some holes in lux to ppfd conversion. I think it’s fair if you are trying to get a rough estimate on where you have the highest and weakest intensity though.
Only other thing I have to add is that you can’t accurately calculate dli from a single reading. You would need to plot the average for entire space, then convert and use ppfd average to run out dli calculation.
There is no correlation between a lux meter and a PAR meter. Lux is for humans and PAR is for plants. Humans see in a range similar to plants 400-700 nm, but there is a ten fold increase in the way humans perceive the middle green spectrum then the red and blue spectrums at the extremes. Lux meters therefore do not give accurate readings in the blue and red ranges as compared to PAR meters which plants can use efficiently. It is complicated even more because different light sources give off different light spectrums and the lux meters read the human visible light, not the light the plants can use so it throws the measurement off.
I downloaded a lux app and I just use it as a way to test the light in my tent at different distances. I put my phone against the wall on the floor and move my light down until the numbers start falling move the phone and do it again and again and again lol this is so I know how low my light can go before I lose light around the edges of my tent. To me that’s more important than the actual numbers. I can get those from product reviews and independent testing because we all know you can’t trust the numbers given by the manufacturer. Lux doesn’t read light temperatures not visible with your eyes, that’s why the numbers don’t compute well.
Edit = and if anyone cares to know the sweet spot on spider farmer it’s between 18-20" on the sf7000 in a 4x4 and between 15-17’ on the sf2000 in a 2x4
I’m confused lol, sounds like a lot but I will give it a try. My viparspectre 900w full spectrum led is about 36in from the canopy. Want to get it a bit closer but obviously don’t want to burn them. I also have a 3x3 tent. @MeEasy
Need to add a little strip of white paper to act as a diffuser. It works much better. I compared mine with an apogee meter my hydro shop has. We tested under a fluence spydr and the readings were pretty close. The iPhone 12 was much closer than the iPhone 8 but it still wasn’t that far off.
Not true, you can measure same light source with both and say x=y. The problem with using that method is formula can change when light source changes.
To elaborate on the rest of your post, is merely an issue with the way each meter is individually calibrated. A lux meter weights green wavelengths higher than others, just like you said. A par meter should weight intensity from each wavelength equally. There can even be a significant difference from one par meter to another. Several of them aren’t very good at picking up 650-700nm. Apogee’s latest quantum sensor does good job of measuring par spectrum, but it also brings hefty price tag.
This is the ppfd app on android. Unsure of what light source I should select. Those are not the measurements from my light. Light measurements are at the top of the topic from the top of the canopy. @MeEasy @Bobbydigital @dbrn32 @Hellraiser @CMichGrower @Weedlover1
I just have mine set for sun. It doesn’t change much at all between that and led full spectrum
@Akcr What is the manufacturer recommended distances? They normally get close. I did the above to see how low I could go without losing light around the edges of my tent for during flower. I would start at the high number given by the manufacturer and slowly lower a few inches every couple days and watch your plants for a reaction. I watch for leaves to fold length wise (taco) once you see this go back up a couple inches. Write the number down but it probably won’t be the same on your next grow plants are all different but after awhile you’ll get better at reading them
I think that it’s off a bit though, had to keep lowering it when they were seedlings. I have both veg and bloom on so it tends to get a but hot in the tent. @MeEasy
I set my app to natural daylight 6500k, reading without the paper over the camera was 800 ppfd and 52 DLI. With the paper it came out to 75 ppfd and 4.8 DLI. I lowered the light down to 30 inches above the canopy to get those numbers. Almost identical to yesterday’s numbers even though the light was about 3in further away. @Bobbydigital