PAR and lighting

Discussion in 'Lighting' started by Phishphin, Aug 7, 2014.

  1. PhishphinWell Known MemberMember

    Ok, so we all know that PAR is how to discuss a plant's lighting needs, however, we all still use the terms "low, moderate, and high" as describing a plants lighting needs. So... is anyone aware of a resouce that breaks down where low, moderate, and high fall into regarding a spectrum of PAR?

    For example... My Finnex Ray 2 DS has the following PAR data...

    6 inches from surface = PAR 166
    12 inches from surface = PAR 80
    18 inches from surface = PAR 60
    24 inches from surface = PAR 44

    My tank is 20 inches deep with 3 inches of dirted substrate, meaning my ground cover dwarf sag will receive just above 60 PAR (20-3=17) while my Wisteria and Ludwigia Repens are maybe only 10 inches from the surface, so their PAR received is over 80.


    Question: What PARs are considered low, moderate, and high? I know folks grow dwarf hairgrass at around 30 PAR, which is a "moderate" light plant... so does that mean I'm running a high light tank? Or does high light mean an even greater PAR!?
  2. JimWell Known MemberMember

  3. PhishphinWell Known MemberMember

    Yeah, I visit that site a lot for plants, but was still having trouble nailing it down. It all seems really subjective. The consensus appears to be low light is a PAR of 15-30, moderate PAR is 30-50, and High PAR is anything over 50. Neat.

    If anyone wants to correct this, please add your :;2cents


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