lol! Thank you. I actually did find a really useful article here and whereas I haven't yet delved into this far enough to land in the pot grower forums, I figure it's probably coming lol.

( http://www.greenhouse.cornell.edu/structures/factsheets/Greenhouse%20Lighting.pdf)

that explains how/why using FC to determine lighting for plants is really not effective. It goes on to explain how o convert instantaneous light intensity to light integral (which is the accumulated PAR during a given day) understadning that at noon on a cloudless summer day you have an light integral of 65mol/m2/day gives a better understanding (for me at least) that a "low light" plant would do fine with 25mol/m2/day. So using a light unit converter app (free) lets me convert 183 instant read FCs into LUX (1968 lm/m2) or PPF (36.45 micromols/m2s) or SW (18.41 W/m2).

PPF is useful is determining the TOTAL amount of PAR that is produced by a system but to know how much of the PAR is actually hitting my plants and therefore being useful to my plants I would need to know the PPFD, which is the amount of PAR that arrives at any given spot (spot test).

(Let me tell you honestly that this is WAY more information than I though I would ever know/need to know about lights for my kind of typical houseplant scenario and I am still not sure that I have fully processed all the information. And none of the information that I have been able to find answer my question of "does 1500FC mean 1500 over the course of a given period of time , i.e. 107fc an hour for 14 hours produces 1500fc a day, OR does 1500FC mean 1500FC for every hour, i.e. 1500FC for 14 hours produces 21000FC in a day)

I know that I am probably rambling and am definitely overthinking this but my concern is not, am I providing to MUCH light, my concern is, am I providing ENOUGH light

Quite the rabbit hole isn't it? I think I came across that PDF a few months ago and didn't bookmark it.

If your plants are healthy, booming when they are supposed to, it's obviously enough (for your Orchids). Your other houseplants ....

lol... rabbit hole? yea that's one way to look at it. Another way yo look at it is, just one more thing for me to needlessly obsess over since all of my plants are doing well. If we are being honest I will tell you that I have a tendency to overthink things like this. In all my years of growing my houseplants I have never once worried about PAR or even FCs. I "know" if an area is highlight or low light/humidity so I know which plants to put where or if I need supplemental lighting/humidifiers (like for my orchids). The only thing I can't grow is spider plants....and I usually toss my ivies after about 18 months cause they get legging yet sparse in the middle but I think the 5-1-1 that I just made up, along with regular cutting back to encourage better ramification may fix that problem.

I came across this link: https://fluence.science/science/how-to-compare-grow-lights/. It seems to cut through most of the 'confusion' surrounding grow lights.

(they're in the business of selling 'white' grow lights, but the 'science' bits seem correct)

Jen: Does "1500 fc" mean over the course of the day, as in take 150 times 14
hours of exposure =2,100 fc and so that we are aiming for 1500 fc
cumulative over the course of the day or does "1500 FC" mean that for an
8 hour day a plant should be receiving 1500fc/hour of light for every
hour of the day?

No. FC (foot candles) is a measure of intensity of the light. If your plant needs 1500 fc then the light intensity should measure that at the plant level. For comparison direct Sun light is about 10,000 fc. 5000 fc is plenty for most light loving plant. 1500 fc will be on the low side.

If you multiply FC by hours that will be a measure of daylight integral. It should be called foot-candle-hours (let us call it fch). So 10hrs of 1500 fc light would be 15000 fch per day. Although, technically daylight integral is measured in micro-moles per unit area per day. Plants need a certain amount of light per day to make enough photosynthate for growth. And then enough rest period to reset themselves for the next cycle.

@tropic: you stated that far more succinctly than I.

"Word on the street" is a 6-8 hours or so of darkness per day.

lol, thank you both so much. I turn my lights off between 11 and midnight and then back on again 7AM so the "time" they are under light is plenty long enough. I do think it's time to change the bulbs in my "grow lights" lol

Hey funky......I found the cannabis forums......lol...too much!!!!

Learned a lot from those forums over the years. I even built a few lights with individual components. They have it down to a science. But for us who do not have such an obsession with the best it is an overkill.