this winter, the 60's have been about as low as it gets. today for example, was 80 degrees. just like yesterday. those are the days that puts my system out of wack. and its only going to get warmer from here as we are only in Feb.
With regard to the LED height, I had it waaaayyyy too close early on, but it wasn't for long. for about 3 days i had it at 12" while i was still fine tuning the enclosure. from there i moved it up to about 18" but even at that time i was having over 90 degrees in the enclosure....again, as I was finalizing the design....I was hoping to take advatage of a southern US winter and harvest by summer, but that hasn't quite panned out like expected.
with all that being said, now that I KNOW my temps are ok, I can really start to play with the light to get the right height. i did notice that when I had it at around 23" i was getting good growth, but seemed to have some stretch.