As Cary Mitchell, a horticulturist at Purdue University told NPR, in the 1990s, “research showed that you could grow lettuce in just red light. If you add a little bit of blue, it grows better.”
Any plant can grow with "artificial" light. It's just a matter of generating the correct light spectrum for a plant. There's nothing special about the light coming from the sun.
Well sunlight is full spectrum colour plus ultraviolet and infrared. I'm sure there are benefits to the plant we can't easily measure, since they evolved with full specteum. We found a LED grow bulb with a yellow LED besides RED and BLUE, the plants grow like crazy
That's going to be less efficient per watt though, plant's are green because they don't use the green light, hence red+blue grow lights.
Not all plants reflect the same range of wavelengths though, and different plants will use different wavelengths to grow. This is basically an exercise in finding which wavelengths we can drop without significantly slowing growth for each plant.
Most plants do. That's why they're green - they reflect the photons from the mid range, and absorb the ones from the extremes (red and blue/violet) to actually work their shit. Like this:
I dont know about need, but a lot of weed farmers feel that plants do better with a rest/dark period. I haven't noticed a difference but give them a rest period anyway as its "natural"
I tried growing a plant in a closet once. The instructions I was given were to leave the light on 24/7 until it was as big as I wanted, then to switch to a 12 on/ 12 off cycle to get it to bud.
I didn’t try very hard on it and ended up with a quarter of mid weed after like 6 months
Got the wife an aerogarden for Christmas. We’ve been growing a ton of herbs indoors with just the led lights for months. Wait til you find out you don’t even need soil to grow stuff