Lux meter giving me stretchy seedlings

Discussion in 'Lighting' started by NoaLeaF, Nov 3, 2023.

  1. I am currently starting 3 seedlings under an HLG 100 R spec.....bought a Dr meter pic meter because I can't spend the money on an actual ppfd meter....was told it will work with the light I have.....I went on the high end and positioned the light so that the lux meter read about 7000.......the seedlings are now so stretchy like 4 inches tall just opened up on top with the tiny leaves lol. What the f is going on? I always seem to go back to feeling like it's my first time every time I go from finishing a flowering cycle back to seedlings I feel lost. I'm fairly new but haven't had this issue in the past and feel like I just kept the light around 24" at 100 % and had no issues but if you measure with a pic meter that reading is bogus like 15000 or something which is supposedly way too high. Any suggested hanging height and dimming for this light with seedlings?
     
  2. Dr meter #lux meter (typo)
     
  3. Go by what the plants tell you, not some questionable light meter.
     
  4. I run 20.000 lux over my seedlings but that's just me. With light at 18 inches above
     
    • Agree Agree x 1
  5. Ok so that's what I wanted to say is that it seems from what I previously did...that I need to just double the suggested Lux and go by that with the meter ....the height and dimming is way to low when I adjust with the meter for 7000 lux. The meter isn't that questionable I had a lot of people on here recommend that exact one....just seems you have to go by higher lux settings for the plants.....like if they say 7000 use the meter to get 14000
     
  6. Is that at 100%
     
  7. And what wattage light are you using
     
  8. Heavens no, my light would put out 100.000 lux at that distances .
    In the grow journal under double grape auto you can look at what I did with my seedling.
    I will have to go back myself and check just to make sure.
     
    • Like Like x 1
  9. 350 watt led QB
     
    • Like Like x 1
  10. Ok....I just saw a guy on YouTube with a meter and it read 5500 lux over his seedlings and they weren't stretchy....trying to figure out what happened with mine....weird
     
  11. 20.000 lux is 320 par
    You will just have to play with the power setting until they don't stretch and leaves start to get bigger.
    Good luck you will get it.
     
    • Agree Agree x 1
  12. Download the photone app. It's spot on and it's free.
     
  13. Another thing is if you got a fluorescent light to put over them they won't stretch.
    You can put it 1 inch above seedling.
     
    • Agree Agree x 1
  14. No you can't use a Lux meter on a LED light, unless correctly calibrated, one uses Lu on the HPS the other being LED is measured in PAR, you can download an app that gives a rough indication of PAR reading from your phone,
    or better sift thru the info on the web, being PAR specs for that light, set the conditions and go from their
    IMO see Bugbee on YT
    check the link: https://forum.growweedeasy.com/foru...1-hlg-100-rspec-setup-what-distances-are-safe

    good luck

    ps try this but its a rough average: https://www.waveformlighting.com/horticulture/convert-lux-to-ppfd-online-calculator
     
  15. I am with Clearsky. Try ~20K lux. Maybe 17K.
    @Vee been using a lux meter with led for a long time.
     
    • Informative Informative x 1

Share This Page