Jul 15th, 2010
LED Grow Lights – What’s The Big Deal?
Grow lighting is not new; it’s been used for many years by plant growers to enhance and even supersede light from the sun. What is new however is LED grow lighting, which has sparked some pretty sharp debates about its effectiveness. This article briefly reviews what these new lights bring to the table and why there is much about them.
There are two main reasons why LEDs started being used for grow lights. First, LEDs are the most efficient form of lighting available. They convert most of the energy they consume into light and thus give off very little heat. By comparison, traditional HID (high intensity discharge) grow lights produce considerably more heat than light.
Second, unlike regular incandescent type lights which spread light across a wide band of the spectrum, LEDs can be manufactured to emit light only at defined wavelengths. The advantage being that plants in fact only absorb light from two specific parts of the spectrum. So LED lights don’t waste expensive electricity by generating unwanted heat and unusable light.
These combined attributes – low electricity consumption plus accurate targeting of key parts of the spectrum – account for the great interest in LED lights. The promise of improved light delivery and reduced operating costs was bound to attract attention.
Another associated advantage of running with practically no heat output is that LED lights can be positioned much closer to plants without risk of burning. The reason for doing this is to take advantage of the inverse square rule of light. Put simply, halving the distance from the light source quadruples the amount of light delivered.
With HID grow lights the blue component requires a metal halide bulb while the red needs a high pressure sodium one. It is necessary to physically switch between these two, and also to replace bulbs on a regular basis (about annually). LED systems simply allow the balance between blue and red to be varied; they also last a great deal longer (like about 10 years).
So what’s the problem then? Well, there really isn’t one where the technology is concerned. High quality modern LED lights can match or outperform conventional HID units while bringing a whole host of other benefits as noted above. What is a problem is that quite a bit of what gets sold as LED grow lights is low quality and outdated.
People need to have realistic expectations. An LED UFO grow light using 90 separate 1w LEDs will perform as well as a 400w HID, but people get seduced by apparently cheaper alternatives. So they’ll be tempted by a unit with 225 LEDs and total consumption of 14 watts. That means each LED delivers only 0.06 watts of power which is way too low to ever work for grow lighting. Inevitably then the poor reviews arrive and the reputation of all LED grow lights suffers as a consequence.
For much more on this subject I recommend these additional articles that explore further into modern LED grow lights and indoor growing.
categories: LED grow lights,grow lights,LED lights,HID grow lights,growing plants,indoor gardening,propagation,gardening,plants