GuestPost: The LED Grow Light Advantage

So you want to start that vegetable garden, but your climate is too cold to get our seedlings going outside in good time? So you need to start your plants inside, or in a green house perhaps. But you don’t have a green house and you don’t have a sunny windowsill to grow them on either. So a setup which includes indoor LED grow lights may be your best option. That’s what this guest post is all about. Ed.
While HID solutions currently remain the most popular type of lighting for indoor plant growth, many homeowners are starting to discover the greater efficiency of LED grow lights. HID lights (high-pressure sodium, compact fluorescent and metal halide types) are more widespread for a couple of understandable but invalid reasons. They emit light that’s much brighter to the human eye, and they cover a broader spectrum of light than LEDs cover. In fact, most HID grow lights sold today use full spectrum bulbs. LEDs, on the other hand, have a couple of more important advantages.
Better for Photosynthesis
When people look at HID and LED grow lights side by side, they’re attracted by the brilliance of the former. It appears that plants are would get more light from an HID. The light spectrum argument is less of an issue now that LEDs have evolved from only producing light in single color bands to producing mult-band and full spectrum light, depending on which type of bulbs are purchased. While full spectrum LED grow lights are available, they’re not recommended, any more than full spectrum HID grow lights.
What really matters is the quality of light needed by plants, not by humans. A tri-band LED grow light produced light primarily in the blue, red and orange bands of the spectrum that comprise the range known as Photosynthetically Active Radiation, or PAR. PAR is what chlorophyll reacts to, and what induced photosynthesis in plants. The light bands produced by HIDs that are most pronounced to humans, such as green and yellow, are of little use to plants. This is why only 10% to 15% of the light produced by HID is used for photosynthesis, compared to the 90% of light produced by LEDs.
Better for Power Efficiency
LED lights run at a much lower temperature than MH, HPS or CFL grow lights, which is one of the reasons they last so much longer. An HPS grow light can only last about 5,000 hours, while an LED grow light can literally last 10 to 20 times as long. Their lower heat also lowers the risk of burning plant leaves (some have cooling fans to reduce the temperature even further for more delicate plants). Another reason for their longer life is the lower power consumption—they draw 40% to 75% less power for the same yield than MH or HPS lights. While LEDs aren’t always the best choice for general purpose household lighting, they’re ideally suited for the purpose of indoor plant growth.