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.
The light intensity of artificial lights for home use is generally low in comparison to that of sunlight. Two Cool-White lamps will provide an intensity of about 400 foot-candles at foliage heights about one foot from the lamps. This intensity is minimal for the growth of most plants adaptable for indoor growth.