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What's your ppfd goal at canopy for flower and veg?

i’m testing a few lights and curious what other growers shoot for re: light levels in both flower and veg?

i have the capability to hit about 950 in flower but that’s pushing towards bleaching and light burn. i’ve heard 750 often but wanted to throw it out there.

re: veg, i really have no idea past clone/seedling stage. how much is too much? 200 too low? 500 too high? i need to outfit a veg space and currently using spare hid which is not as economical as it could be.

thank in advance for your input.


I think we are all figuring this out together, I find it to be cultivar dependent and some get fatigued with LEDs and newer fixtures. 900 seems to be a good fit in bloom to hit 40 mols and in veg we are near 350-500 but again it is strain dependent and also type of light seems to be a variable in there also.



Our own research has shown that up to 1,200 µmol/m²/s can be of advantage in combination with CO2 fertilization, higher temperatures and altered watering regimes… But the following facts have to be considered as well:

  • the spectrum should include enought green and yellow light because otherwise the photo receptors of the plant can be damaged (due to too much blue and red light) and because the green-yellow light can penetrate the cannopy much deeper…
  • the light should be as homogenious as possible: at least ±20%
  • the light should be as diffuse as possible and the distance between the lighting source and the plants should be at least 400mm: Thats important because if the light source is to close the closest part of the plant will shade the lower regions and therefore most of the light will be reflected back or even damage the upper part of the canopy. That is for example a problem of the SPYDRX-like approaches…