Ask Erik - Pros and Cons of LED Lights

Hello Dave,
Light Emitting Diode (LED) technologies look to be NASA’s first choice in grow room construction. LED lights are an extremely efficient light source, and the spectra can be tailored for plant growth functions, so no energy is used to produce wavelengths that the plants will not require. In fact, plants grown under LEDs can look more black, as no green light is being reflected. Green-light wavelengths are typically not absorbed by the plants, but reflected. For aesthetic purposes, LEDs can be tailored to allow plants to receive light wavelengths similar to the sun’s spectrum. But this means energy is being used to create wavelengths that the plants do not require.

LED lights last much longer than HID lamps and their lumen to watt ratio efficiency is considerably higher. Although LEDs are a very efficient source of light, they tend to lack the sheer intensity that metal halide and HPS lighting systems offer. The individual LED bulbs are very small and are banked together to produce higher lighting intensities. However, the distance at which they emit light at higher intensities is not very far.

In my opinion LED lamps would be very well suited for production of low growing crops such as greens, herbs, and dwarf vegetable varieties. Because LED lighting can be tailored to very specific spectral outputs, they could be used to supplement conventional HID-lit gardens to produce crops of higher quality. They can also be used to maintain a vegetative lighting cycle while the HID lamps are running 12/12 to conserve power and allow the use of “flip-flop” relay systems in the vegetative growth phase.
LED lamps would be extremely well suited for the propagation of seeds and cuttings. They emit little heat and provide gentle and even lighting, all within the exact light wavelengths the plants require. Small-scale closet-style grow chambers could be improved with LED lighting.

At present LED lighting is more expensive than conventional HID lighting systems. But the lack of heat they emit means that exhausting or air-conditioning grow room air will be minimized. The LED lamps operate only a few degrees above ambient temperatures. They can also be mounted at any angle so that all parts of the plants can receive light.

A colleague has a friend who finished a crop exclusively using LED lighting. Reportedly the quality of the smaller stature plants was extremely good and the plants appeared exceptionally healthy while growing. The yield was modest.

Any growers who have tried this or any other new technology should feel free to drop me a line here at Maximum Yield to share their experiences and opinions.

Cheers,
Erik Biksa