Qualm entered English in the 16th century, with meanings like doubt and uneasiness.. Usually a qualm comes from doubt about an action and a feeling that you are doing, or are about to do, something wrong. It isnt a bad feeling about another person's behavior but about your own.
The newest type of grow lights use LED technology. One major advantage to the LED lights is the small size. LED lights are only a few inches in diameter and are easy to mount. In some greenhouses, LED lights may be the only practical light option.
Plants are most affected by blue light and red light. The color of light is a major consideration when you grow plants indoors. Fluorescent light that contains lots of blue light is good for starting seeds indoors. Full spectrum fluorescent light will encourage growth and flowering.