A note on measuring Lux/Foot Candles with LEDs. When measuring what is the proper amount of light for plants using LEDs, your number will be necessarily lower than if you were measuring with a less restricted spectrum light source. To find the optimum level without any adverse effects but still providing maximum light energy, I placed my light meter at the top of the canopy of Group 1 where the leaves were thriving & healthy - any closer and they exhibit heat stress/light overload. As plants get older, it seems they are more able to withstand closer distances.

The tops of the canopy of Group 1 produced a range of 8500 Lux - 9000 Lux. As they are the oldest they are able to tolerate more light.

For Group 2 , the light distance was adjusted to be closer by a few inches and the light was made more even. Initial readings were in the range of 2000 Lux - 5000 Lux, decreasing as it neared the edges. New readings after adjustment were 3500's - 6000 Lux. The light was considerably improved in terms of evenness and intensity.

Group 3, Units 1 & 2 had the Procyon height adjusted closer and had initial readings ranging from 1500 - 5000 Lux. After adjustment the range was high 2000 - 5000 Lux. Unit 3 as put under 3 T5 lights at a distance of 1 inch away.

It's a lot of trial and error and not much consistency to go by as the plants do tolerate more light as they age. Your only guide is the approximate height given by the manufacturer (24" - 36" with the Procyons which has proven true) and watching for inverted leaves. However the values I have gathered seem to be where the plants absorb the most light without getting heat stressed.
Apollonia Reviewed by Apollonia on . My First Grow: Aeroponics, LED veg, Super HPS flower, CO2 sealed room Procyon LED veg, Super HPS Flower, Aeroponic, General Hydroponics, CO2 Strains: Cinderella 99, Apollo 11, Blue Apollo, Sugar Blossoms, Sugar Berry, DJ Short's Blueberry (F2 from Joey Weed), C99 X A11, C99 X BB All plants have been grown from seed and a mother will be selected for each strain, except for Cinderella 99 which will have 2 mother plants for the different phenotypes: grapefruit & pineapple. I plan on flowering & harvesting all other female plants that are not selected to be Rating: 5