Didymium Glasses

The lighting you choose depends on your purpose. Plants in a vegetative cycle thrive under a blue spectrum. This blue spectrum, more than any other, promotes chlorophyll production. Too much of the red spectrum during this early growth phase can cause internodal stretching. These red spectra are what plants utilize for flowering. The intensity of your lights/lumens they produce also play a large factor in the penetration of your leaf canopy and density of the buds you produce.

There are four major modern lighting groups. The first to be developed was the incandescent bulb. While these bulbs have faithfully lit our nights for over a hundred years, they have never been practical for flowering. Even for supplemental lighting they are marginal at best, with a lumen output that is small - compared to the wattage they consume. The only reasonable application for these lights would be using green ones for allowing you to work in a flowering room during its dark cycle.

Much of the green light is not absorbed by plants, so they appear that color; there is no worry of interrupting photo-periodic response. The second lighting groups are Low Intensity Discharge, commonly known as fluorescent. These tubes have a phosphor coating that emits visible light as electricity excites the mercury vapor contained inside.

While these lights do produce ultraviolet radiation; in most, the amount is trivial. An eight-hour exposure would be equivalent to a minute under the mid-day sun. The greater health concern is exposure for long periods under cool white fluorescents. These lights have a profound physiological and psychological effect from wavelength energy penetrating the skin and acting at the molecular level. Fortunately, full-spectrum lights help eliminate these concerns.

Fluorescent bulbs are much more efficient than incandescent ones and are an excellent choice for growing. Vegetate using full spectrum 6500K bulbs for the blue spectrum. Fluorescent bulbs can also be used for flowering as long as you do not grow the plants over two feet tall by completion, and keep the lights within a few inches during their lifetime. A mix of three or four 3000K for a nice red spectrum to one 6500K will provide a modest yet wonderful harvest of medicinal delight.

The third group creates light by an electric arc in short tubes filled with various gasses and mineral salts, which become electrified into plasma. These lights are known as High Intensity Discharge lamps. Of this HID group, two are most commonly used in growing: metal halide (MH) and high-pressure sodium (HPS). At one time they were only available as such, now there are some crossover bulbs having more of each other's spectra. MH is traditionally used for vegetation; some growers feel that even though flowering under them does not produce the quantity, the quality is greatly improved, giving off a light similar to sunshine.

Just like the sun, they also give off a good amount of ultra-violet (UV) radiation. Some people compare exposure to snow blindness, so wear sunglasses with UV protection whenever you are working around them. HPS lights can produce large and delicious flowers, but growing vegetatively under them will cause serious stretching. The bright, yellow-orange light is not damaging to the eyes unless you look right at it, but it can be uncomfortable and makes it impossible to see colors accurately.

Luckily, the sodium flare produced by these lights is similar to the ones that glass blowers make working with borosilicate, and there is eye-wear that eliminates those orange spectra. This eye-wear allows you to see the true color of your plants and spot nutrient issues several days before they would be obvious to naked eyes. In a hydroponic system or in soil, this few day heads-up could save your crop. These glasses, called didymium, were developed a generation ago by Aura Lens and are distributed by great glass suppliers like ABR Imagery.

They have purplish-pink lenses and start at around thirty dollars. Mercury vapor (MV) is last type of high-pressure light used in growing. These lights were banned in the US in 2008 and will be in 2015 by the EU, because they give off cancer causing UV-B rays. If you decide to use mercury vapor lights for supplemental lighting, make sure you TURN THEM OFF when working around them. The reason some growers would choose a potentially dangerous light has to do with the historical origins of Cannabis in the Parvati Valley, at the foothills of the Himalaya range.

The light at this altitude contains a larger amount of UV-B rays, and there have been several studies showing that THC levels in particular strains increased in direct correlation to UV-B light. This THC production in the plants may be acting as a photo-protector (like melanin does in humans) dissipating the harmful rays. All of these lights give off some serious heat energy, so be careful with how close these lights are to your plants. The fourth and final of the lighting groups is the Light Emitting Diodes, or LEDs.

They produce light from tiny semiconductor chips, imbedded in a plastic housing, and are usually from three- to eight millimeters in circumference. LEDs can produce light across the ultraviolet, visible and infrared spectra. Three years ago I would have said, save your money; wait till the technology advances. Now I would say: make sure your purchase is from a reputable company, as not all LED panels are equal. LEDs are, at this point, comparable to fluorescents and are on their way to challenge HID supremacy.

Some people believe that - with their power consumption up to half that of an HID and a much lower heat signature - not only do they compare, but they are better for small space and stealth room applications. Most LED lights are classed as one or two under the laser safety guide for maximum permissible exposure.

This basically means they are pretty safe, as long as you are not staring directly at them - your blink reflex will limit your exposure as you work around them. As these lights become more specialized the spectra available will increase. Just as fluorescent bulbs are now available with increased UV-B radiation, LEDs will be as well. These lights will either need to be turned off; or, at the very least, special clothing and eye protection ought to be worn around them. Whether you are a professional, novice, young or old; if you spend a brief or extended time under the lights, protecting your eyes is important. If we live long enough, most of us will develop cataracts. There is no reason to speed up the process. Wear the proper eye protection. UV lenses are available from clear to Limo. Get some polarized lenses to reduce glare or a pair of rose-colored didymium glasses to see the true color of your plants as they flower in the warm light. Take care of yourself, so that you can see your future grow.