Ok so first off, yes i am highly medicated at the moment, and yes im sitting on the porcelain throne... So now that we got that out of the way, can you really have too much light in your grow tent? Like take my little veg tent for instance (2ftx2ftx5ft tall). If i managed to cram 12 vero29 cob's inside my tent with a total power draw of 800 watts and i was able to keep my tent at optimum temperatures, would it be too much light? Has anyone ever tried to find out how much light is too much? Could i just make a mini sun and cram that sukker in there haha?
Yes;
So from the chart you can quickly see two things; first, there's no point in ever going over 1500PPfd, and second that you get the vast majority of plant growth response at as little as half of that value.
In other words, no sense in blasting them; you run into diminishing returns fairly quickly and going overboard is definitely harmful.
Not to mention expensive; not only do you have to pay to generate all that light but even with COB LED you will still need to remove all that excess heat, another slightly more hidden tax on high intensity gardens.
Two or three sweet spots present themselves;
One is at about 450PPfd, where over half of growth is simulated with less than a third of maximum intensity. Not surprisingly, this is the realm of those seeking really high gpw numbers, but it isn't as space efficient for someone with a big monthly rent bill, leading to...
The second, at around 850PPfd, is going to give 75-90% of the best possible plant growth with just over half the intensity- and now we're talking some real big yield per square foot numbers without going crazy trying to keep things cool.
The third sweet spot is all the way up above 1250PPfd, and seeks to maximize returns per unit of space, power bills be damned! The only way this level makes any economic sense at all is if the value of the crop is high enough.
Yes, sunlight can and in hot, dry summer conditions often does exceed a plant's ability to absorb light effectively.