more darnkess a good thing or a bad thing for plants?

always been curious about this. lets say for example you give your plant 3 hours of light a day and 21 hours of darkness every day would a light cycle like that help the plant with the flowering process and bud formation or will it hurt the flowering process and lower bud formation?

It would hurt the process. Plants absorb light energy and use it to grow. Less light energy=less growth, to a point. If a plant doesn't have enough nutrients to make use of more light, than more light won't help.

You can sometimes stretch your light period to 13h with 11 dark and help your plants. But you cannot go the other extreme, the plants need good light to develop.