Lights generally are rated in lumens which matches human perception of brightness. Another method is to measure flux - just count photons like it's rain. Meters to measure light that way are available, like from apogee. They measure ppf photosynthetic photon flux in umol/m^2/s.
In theory, it should be a fair way to compare any light source but I don't know since it counts green photons with the same value as blue ones - better then lumens which counts green ones higher but maybe still not perfect.
I got one and it's pretty usefull to check the light level and distribution before your plants tell you.
Full summer sun = 2000 PPF
Full winter sun = 1200 PPF
Typical hps setup at plant tops = 400 (12 hour average similar to full winter sun)
I measured my LEDs at different points and found
<50 = not enough light, plants stretch don't fill out
50-100 = healthy plants, good level for clones/transplants
100-200 = strong growth and flowering
200-300 = too much light, plants stay short (okay for end of flowering)
>300 = stressed out plants, leaves wrinkle
I checked the grow area that is greater then 100 and it's really more like 6 square feet for my superled (similar to the procon 100). So if a 400W HID gives 400PPF over 10 square feet then my superled is a bit short of that....
Having the more ideal spectrum gives the LEDs maybe a 2X performance advantage in terms of PPF over hid and they are at least 2 times more efficient in terms of photons per watt.
Anyone else have these meters? Please report what measurements you think is "enough" light for veg and flower. Also, please correct anything I've got wrong.
In theory, it should be a fair way to compare any light source but I don't know since it counts green photons with the same value as blue ones - better then lumens which counts green ones higher but maybe still not perfect.
I got one and it's pretty usefull to check the light level and distribution before your plants tell you.
Full summer sun = 2000 PPF
Full winter sun = 1200 PPF
Typical hps setup at plant tops = 400 (12 hour average similar to full winter sun)
I measured my LEDs at different points and found
<50 = not enough light, plants stretch don't fill out
50-100 = healthy plants, good level for clones/transplants
100-200 = strong growth and flowering
200-300 = too much light, plants stay short (okay for end of flowering)
>300 = stressed out plants, leaves wrinkle
I checked the grow area that is greater then 100 and it's really more like 6 square feet for my superled (similar to the procon 100). So if a 400W HID gives 400PPF over 10 square feet then my superled is a bit short of that....
Having the more ideal spectrum gives the LEDs maybe a 2X performance advantage in terms of PPF over hid and they are at least 2 times more efficient in terms of photons per watt.
Anyone else have these meters? Please report what measurements you think is "enough" light for veg and flower. Also, please correct anything I've got wrong.
