Few things in life are certain, but this we can say for sure: The budding herbal marvels you grow indoors need a lot of light to make their magic bloom. For most urban homesteaders, that means tried and true high-pressure sodium (HPS) grow lights, which come in versatile sizes, are easy to maintain, and have historically offered the best ratios of yields produced to electricity used.
LED lamps have been gaining a lot of ground in the past few years, and the latest fixtures on the market are starting to reach a balance of cost vs. efficiencies vs. harvest. LEDs are super energy-efficient, produce less heat, can be placed very close to plants so little light is lost and can be plugged into the nearest outlet — no ballast needed. Some growers even report LED’s wavelength positively affecting crop quality. However, a 2014 greenhouse lighting study found that while HPS and LEDs are largely equal as illuminators, LEDs’ initial cost is 5 times higher than HPS for the same amount of light produced. For most indoor urban growers, that’s the difference between home-grown and home loan.
This disparity is expected to continually shrink, and eventually vanish, over the next few years. Until it does, we think HPS is still the best and most economical option for the indoor urban grower.