It’s the same for plants. You can shine a 150 W metal halide lamp at them for 10 min, and it will probably be the same as pointing a 15 W lamp for 100 min. You can expect the phyiology behind this to be much more complicated, but that’s the rough idea.
The total light absorbed by the plant is termed the “Daily Light Integral” (DLI).
We exposed 2 species of plants to different DLI levels. The plants are:
– Philodendron Gold
– Dracena Surculosa
The DLI levels range from 4 molm-2day-1 to 0 molm-2day-1. (In layman terms, from a bit of exposure to light to complete darkness).
This experiment has been going on for 16 weeks. We should be wrapping up in 2 – 3 weeks.
From this experiment, we can see how low the lighting level can go for these 2 plants before they croak.
The purpose of this experiment is to answer the qn: If I am providing artificial lighting for indoor plants, how do I keep my lighting bill as low as possible?
By finding the minimum lighting levels needed for each plant, we can turn the lights off after we know they have had their fill. This means savings electricity and $$.