help..my leaves are droopy

[CityDweller]

I've done a fair amount of research into this and for a number of the apps I would agree but not for all.

Photone recently tested their app (and many others) against two fully calibrated lab level light meters and the accuracy results were on IOS it was within 2% and on Android within 9%. Now 9% sounds like a lot but as this is an amateur grow I would still accept that as an respectable margin of error. Light into plants is not so exact that having a DLI of 18 or 22 instead of 20 is going to kill your plants. I would also question the manufacturers guidance as being any better. Their testing is done in their tents, in their environment and that's not necessarily any better or more accurate than the best phone light apps out there.

MJ

I tried Photone and it was off by about 40% for me.

[mpsj]

I tried Photone and it was off by about 40% for me.

I've seen Photone perform differently on different cell phones. My phone is a 2022 model so perhaps the components play a role in their performance.

[CityDweller]

I've seen Photone perform differently on different cell phones. My phone is a 2022 model so perhaps the components play a role in their performance.

I am using an s22 ultra. My guess is that it responds differently to different LED's.

[mpsj]

I am using an s22 ultra. My guess is that it responds differently to different LED's.

Side-by-side I've witnessed two different phones using Photone exhibiting different readings for the same light source. Each phone however was consistent in their own right relatively speaking.

[CityDweller]

Side-by-side I've witnessed two different phones using Photone exhibiting different readings for the same light source. Each phone however was consistent in their own right relatively speaking.

I still feel that if you want to grow by PAR for growth stage, it is best to follow the light manufacturers recommended as they take their reeding using quality meter. The phone apps are usefull for monitoring the lights over time to see how they hold up with long term use. Jmo.

[MadJohn]

I’d like to own a really good, expensive PAR meter but that ain’t happening. I believe it’s important however to understand what your particular lights are emitting in terms of spectrum and strength. There’s enough research out there to show relationships between light science and plant growth. I’m using the Photone app in my Samsung S22 simply as another control element my current grow. I’m not concerned whether the Photone readings are true absolute values. I find the Photone app readings on my phone consistent enough to rely on them "relatively" speaking. With the help of guidelines from light charts I’ve used Photone in my current grow since day one... especially during veg. I can grow without light meter readings, but find monitoring my grow lights to be another useful tool in the box. JMO

Very well said.

I've been pondering this a lot, being new to growing. It seems LED technology has rapidly evolved over the last 10 years to the point that even $100 lights can give an excellent spectrum these days. In that sense going with any of the major brands on the market will see you good. I think the spectrum thing is "sorted" on any modern reputable grow. There's always improvments to be made but you only need to look at this forum, and others and you can see some exceptional grows you could only dream of 20 years ago.

As for strength of light I agree. I'm a noob, I'm still learning every day and one of the first things I learnt about my LED is that it's insane strong. I've had to learn to turn it down a lot more than I expected. I'm still struggling a bit as I'm growing auto's and finding good up to date info on auto's prety elusive so I'm winging it a bit. I do use Photone almost exclusively at the moment. Seems to be working ok for me but it's just a matter of knowing what DLI I need.

Cheers

MJ

[mpsj]

Very well said.

I've been pondering this a lot, being new to growing. It seems LED technology has rapidly evolved over the last 10 years to the point that even $100 lights can give an excellent spectrum these days. In that sense going with any of the major brands on the market will see you good. I think the spectrum thing is "sorted" on any modern reputable grow. There's always improvments to be made but you only need to look at this forum, and others and you can see some exceptional grows you could only dream of 20 years ago.

As for strength of light I agree. I'm a noob, I'm still learning every day and one of the first things I learnt about my LED is that it's insane strong. I've had to learn to turn it down a lot more than I expected. I'm still struggling a bit as I'm growing auto's and finding good up to date info on auto's prety elusive so I'm winging it a bit. I do use Photone almost exclusively at the moment. Seems to be working ok for me but it's just a matter of knowing what DLI I need.

Cheers

MJ

Here's a DLI guide I've used.

[MadJohn]

Here's a DLI guide I've used.

Yeh that's the one off the Photone site, same one I've been referencing. However that's a more traditional 4/8 cycle seen in photos not necessarily mappable to autos as apparently autos not only prefer less neuts (typically half what photos need) but also less light. But that's the problem I don't know and can't find any really realiable source for autos, just lots of hand waving and "it's a bit like photos only less innit".

A lot of this doesn't matter (or matters less) when you're experienced as you can judge it by the plants themselves when you know what you're looking for but when you're starting out, esepecially with auto's, would be good to have something a little more focussed.

MJ

[barney_b]

I am using an s22 ultra. My guess is that it responds differently to different LED's.

Found the cause. Photone is utter shite on Android. Something about iPhones' sensor make it much much more accurate.

Hell, using my Pixel 5 next to my wife's 12, it was like 2 different apps. The responsiveness was also for shit on my phone compared to hers.

YMMV but yeah, I found Photone useless on my phone.

Cheers
B

[barney_b]

Here's a DLI guide I've used.

Man I really hope FG sees this.. HEY @Farmer Geddon

This DLI chart might actually suggest the cause of stretch marks. Thoughts?


(I'm still not sure where to find the source info on DLI for cannabis. I'd like to see how they've measured "best" DLI for canna at different stages)

Cheers
B