LED Distance help?

Mtt582

Mtt582

Active Member
I’m new to the site, obviously. I am looking for some insight from some experienced growers. My seedlings are a week and a half old. I put them under three fluence Ray 22 LEDs, I cant post the specs because I’m too new to post links, it’s easy enough to find on google but i can also just send them to you a different way if you guys want.
They are in solo cups about 20” from the light. I was advised by some local help that the distance is way too close and I should drop the cups the the floor putting the distance from the lights around 4 feet. All my research has told me by the time you’re plant shows signs that it’s too close to the lights it’s too late. These are some quality seeds and I don’t want to mess this up. Any advice would be appreciated.
 
PotentiallyPotent

PotentiallyPotent

Member
hey bud. I'm no long term expert or anything, but I recently found out about something that helped me with this exact problem. Get a basic laser thermometer on Amazon for 30$ to measure leaf temp. This will make sure you don't burn as easily. (especially with cheaper / hotter lights like the one I have). I recently had to raise one of my lights an extra 8" relative to the nicer one once I got one of these tools. I had no idea one side of my tent had leaf temps in the 80s while 3 feet away was low 70s. air temp was consistent due to air circulation. leaf temp is also great to know in conjunction with air temp and relative humidity for helping prevent mold and stuff so this tool is no one trick pony. for your seedlings though, less is more. as far as I know, seedlings only need enough light intensity so they don't get super leggy. any more than that and it's kind of a waste of energy.
 
Mtt582

Mtt582

Active Member
PotentiallyPotent said:
hey bud. I'm no long term expert or anything, but I recently found out about something that helped me with this exact problem. Get a basic laser thermometer on Amazon for 30$ to measure leaf temp. This will make sure you don't burn as easily. (especially with cheaper / hotter lights like the one I have). I recently had to raise one of my lights an extra 8" relative to the nicer one once I got one of these tools. I had no idea one side of my tent had leaf temps in the 80s while 3 feet away was low 70s. air temp was consistent due to air circulation. leaf temp is also great to know in conjunction with air temp and relative humidity for helping prevent mold and stuff so this tool is no one trick pony. for your seedlings though, less is more. as far as I know, seedlings only need enough light intensity so they don't get super leggy. any more than that and it's kind of a waste of energy.
Click to expand...
Thanks for the info. What lights are you running? and what height did you end up feeling good about? Maybe I can compare and get a decent idea about mine.
 
Chip Green

Chip Green

Well-Known Member
There are bigger issues other than temperature when it comes to LED, it's not the heat that will cause problems, it's the photon saturation. Fluence has some of the better off the shelf lighting available.
I'm not familiar with them personally, but it looks like you have about 150ish watts of good diodes over those sprouts.
It can be challenging to compare one LED lighting source to the next, as far as how high to hang em, because the components and spectrums are so vastly different from unit to unit.
My only suggestion is to use a LUX meter, or possibly a LUX meter app for a smartphone, and a little bit of trial and error...but again I'm completely ignorant to Fluence output, other than what I can read from a data sheet....
 
PotentiallyPotent

PotentiallyPotent

Member
Chip Green said:
There are bigger issues other than temperature when it comes to LED, it's not the heat that will cause problems, it's the photon saturation. Fluence has some of the better off the shelf lighting available.
I'm not familiar with them personally, but it looks like you have about 150ish watts of good diodes over those sprouts.
It can be challenging to compare one LED lighting source to the next, as far as how high to hang em, because the components and spectrums are so vastly different from unit to unit.
My only suggestion is to use a LUX meter, or possibly a LUX meter app for a smartphone, and a little bit of trial and error...but again I'm completely ignorant to Fluence output, other than what I can read from a data sheet....
Click to expand...
waveform lighting has a lux - ppfd converter that I found recently that has a bunch of options for different types of LEDs spectrums. Sounds kinda like what your describing but in all honesty this light intensity stuff is new science/ magic mumbo jumbo to me so I have no clue.
 
P

PungentPete

Well-Known Member
Mtt582 said:
I’m new to the site, obviously. I am looking for some insight from some experienced growers. My seedlings are a week and a half old. I put them under three fluence Ray 22 LEDs, I cant post the specs because I’m too new to post links, it’s easy enough to find on google but i can also just send them to you a different way if you guys want.
They are in solo cups about 20” from the light. I was advised by some local help that the distance is way too close and I should drop the cups the the floor putting the distance from the lights around 4 feet. All my research has told me by the time you’re plant shows signs that it’s too close to the lights it’s too late. These are some quality seeds and I don’t want to mess this up. Any advice would be appreciated.
Click to expand...
I am also a youngster when it comes to growing.. I use COB's.... I use a Lux meter that measures light intensity on a given surface ( a desk or a wall for example or a plant as in our case). Clones and seedlings should recieve 5,000 to 7000 Lux...Vegitative growth should get between 15,000 and 50,000 Lux and during flowering they should recieve between 45,000 and 65,000.. not to exceed 75,000 Lux.. I also keep my lights around 20 inches as stated above...i use T8's for my seedlings for 2 weeks then put them under my COB's.. ... change your lux by moving your lights up or down or you can use a dimmer like I do.. Lux meters are around a 100 bucks on amazon.. make sure you get one for LED'S ( white Light).. there is another type I believe.. hope this helps .. peace
 
Chip Green

Chip Green

Well-Known Member
Plenty of builders (myself included)have $30 LUX meters, and others have successfully used the phone apps as well.
It's not so much as having an absolute accurate LUX reading, it's more about being able to to measure where MY light should be....
 
Mtt582

Mtt582

Active Member
PungentPete said:
I am also a youngster when it comes to growing.. I use COB's.... I use a Lux meter that measures light intensity on a given surface ( a desk or a wall for example or a plant as in our case). Clones and seedlings should recieve 5,000 to 7000 Lux...Vegitative growth should get between 15,000 and 50,000 Lux and during flowering they should recieve between 45,000 and 65,000.. not to exceed 75,000 Lux.. I also keep my lights around 20 inches as stated above...i use T8's for my seedlings for 2 weeks then put them under my COB's.. ... change your lux by moving your lights up or down or you can use a dimmer like I do.. Lux meters are around a 100 bucks on amazon.. make sure you get one for LED'S ( white Light).. there is another type I believe.. hope this helps .. peace
Click to expand...
Thanks, yea any first hand info is great help, my dimmer will actually be here some time this week... 2 months after I ordered it . I know leds are most trial and error from all the post I’ve read the past few months. I just wanna make sure I’m off to the best possible start before I start playing with the variables
 
Mtt582

Mtt582

Active Member
Chip Green said:
There are bigger issues other than temperature when it comes to LED, it's not the heat that will cause problems, it's the photon saturation. Fluence has some of the better off the shelf lighting available.
I'm not familiar with them personally, but it looks like you have about 150ish watts of good diodes over those sprouts.
It can be challenging to compare one LED lighting source to the next, as far as how high to hang em, because the components and spectrums are so vastly different from unit to unit.
My only suggestion is to use a LUX meter, or possibly a LUX meter app for a smartphone, and a little bit of trial and error...but again I'm completely ignorant to Fluence output, other than what I can read from a data sheet....
Click to expand...
Oh I’m not worried about the actual temp. The environment seems great so far, temps around 77 average and the highest I’ve seen it is 81. The only reason I was concerned is cause a couple of the stems are purple/ redish. But those two are also the thickest stems so far. It could be genetics but Im trying to be careful. Thanks for the help downloading the app now.
 
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