Is 1 foot too close to plants in flower? I’m using led lights. Day temp be around 75 and night temp be around 68.
You should refer to your manufacturer. They should be able to tell you how close or how far at life stages…I keep mine 8 to 12 inches away but I have solid led. But I use a mars 2000
Avg is 12-18 inch depending on stage of growth and type of light. Strain can make a difference as certain strains hermie if light is too close or from stress of light burn / heat
Hans is right, every lamp / mfg has height recomendations
There’s a couple things to consider for optimal hanging height. It’s a question of efficiency.
If you raise your light, you’ll have a more even distribution across the canopy area, but less overall light quantity. Lowering the light has an opposite effect: more intensity but you shrink the coverage area.
This is why you see many light fixtures “rated” for say, 4x4 coverage area for veg, but only 3x3 for flower. The higher light demand in flower means you’ll have to drop their light in closer, so the coverage area decreases.
The manufacturer recommendations are trying to strike a balance for you, vs what their light can do. They generally get you in the ballpark.
I prefer to take my own measurements with a PAR meter. I might want to keep my light in closer than recommended for veg, if I’m getting enough coverage, because I can dim it down and save some electricity. For example.