Found this on the fluence led (spyder) website. Nothing new but important nonetheless ...
"So long as carbon dioxide, water, and nutrients are not limiting growth of the plant and it is a fast-growing species, higher light intensities will result in faster growth and increased production of secondary metabolites. However, too high of a light intensity can be damaging to cells, especially in sensitive species, producing free radicals such as hydrogen peroxide within cells. On the surface, you might notice this effect as photobleaching (tan to white patches on leaves) if the plant is not photoacclimated to that intensity. Many growers notice this issue when they are transferring plants from a seedling propagation or rooting phase in which light intensity is low, into a highly productive phase under high light intensity. As a part of the photoacclimation process, highly productive or fast-growing species will likely accumulate more chlorophyll to harvest more light. If intensity is too high, production of various carotenoids (for more info, refer to […pigments & photoreceptors]) is increased to protect the photosynthetic reaction centers and dissipate some light.
(They continue on with)
**** This is why increasing light intensity can have diminishing returns since more light is dissipated in response to higher light intensity **** ...
(Exactly why I've been asking the questions that the "experts" on this thread are refusing to answer for some reason. Listen Im not here to line your pockets. Im here to give my plants the PROPER amount of light and I've yet to hear anyone discussing this on this thread)
To photoacclimate your plants productively with little to no photobleaching (which inhibits growth), it is best to incrementally increase light intensity or use a shade cloth for a week or two. Slowly acclimating plants to higher light intensities can be achieved using dimmable lights after determining what your desired PPFD will be (depending on your fixture capability and species) and creating a series of incremental increases in intensity (beginning slightly above the propagation intensity) over time. A less sophisticated way to achieve this same outcome (if your lights are not capable of dimming) would require you to start with the plant-lamp separation distance much larger than desired and then slowly move the lamp closer to the plants (or vice versa) over the same duration.
As previously mentioned, anthocyanins can accumulate in leaves of many species in response to blue or UV light of sufficient intensity. A similar mechanism protects the fruit of some crops such as tomatoes and peppers. When growing green peppers, you may notice that some fruit surfaces exposed to more light have patches of yellow to orange coloration. This accumulation of photoprotectivecarotenoids prevents damage to the fruit. Lycopene, an orange to red carotenoid, plays a similar role in tomato fruits. Just like most other light-induced secondary metabolites, production of these carotenoids occurs at a faster rate as light intensity increases.
CONCLUSION
We know that the proportion of wavelengths supplied to plants as well as intensity completely changes the photomorphogenic outcomes as well as phytochemical concentrations (secondary metabolites). Increasing light intensity induces production of various secondary metabolites in plants as a form of protection. Blue and UV light have the most powerful influence on secondary metabolism relative to other wavelengths and this scales with intensity. From a production standpoint, these metabolites often improve product quality both due to their medicinal benefits in humans as well as crop coloring effects. This differs depending on the genetics at play with much variability among species. Some species are more tolerant to this response and require higher light intensities to show any response while others do not. One proven method to “get the best of both worlds” is to utilize an EOP treatment in which plants grow and develop under optimal conditions for primary metabolism (broad spectrum), and are then transferred beneath a secondary metabolism promoting light treatment (higher intensity or specific wavelengths) prior to harvest after major crop growth has occurred. Overall, the most important aspect to remember is that secondary metabolism diverts resources away from plant growth. When selecting or making any changes to your lighting system, consider these innate plant responses to ensure your system is optimal for your intended species and market.
(All Im asking is how much quantum board led light is considered too much light? In turn becoming counterproductive to what it is we're attempting to acheive here. Fluence led obviously has no problem whatsoever discussing the subject. I've yet to hear from the experts on this thread concerning the subject)
