Choosing the Right Grow Light

In hydroponic gardens, natural sunlight is replaced by specialized “grow lights” which are especially made to emit the spectrum that the plant needs most. The type of grow light you need, obviously depends on several factors, such as the kind of plant and the plant behavior that you’re trying to elicit.

To understand the concept of grow lights, it pays to know a little bit about color temperature and how it affects plants. In the field of plant lighting, “temperature” refers to color, and not heat. The color spectrum is measured in degrees Kelvin, in the same way as some applications of heat and cold are except higher temperatures are considered “cooler”, and lower ones are “warmer.” The temperatures ranging above 5000K bear the highest resemblance to the intensity and color of sunlight, and are blue on the color spectrum. Fascinatingly, the reds, oranges and yellows are lower temperature, ranging from 2700K and below. The importance of this spectrum is that flowering and fruiting plants tend to do better with slightly cooler color temperatures usually around 4800K, which is still considered in the “blue” zone but leafy vegetation does better in the 6000K range (essentially full sunlight). Plants are also drawing more from the orange-red color temperatures, which are around 2700K, when they are flowering and reproducing. So you can see why the appropriate grow light setup can be so important.

In hydroponic gardening, the three most common kinds of grow light are veered towards the cooler temperatures – as this is most needed by the plants. The first of the most popular types is the Metal Halide bulb. If you want a grow light that resembles natural sunlight the closest, then you should go for High-Intensity Discharge (HID) bulb, Metal Halide bulbs. These are especially good for leafy plants. A second option (also a HID bulb) is the High Pressure Sodium bulb. Producing the orange-red part of the light spectrum (about 2200K), these bulbs are most appropriate for flowering plants but do not encourage full foliage. They are not generally used as a standalone, but in combination with other bulbs and/or natural light. Of course, do not take your focus away from the 3rd most common bulb – the fluorescent, both high- and low-output. Even if they’re not as intense as the HID bulbs, they remain useful especially due to the fact that since they emit so little heat, they can be placed close to the plants.

In more recent days, LED bulbs have been designed, some of which claim to take care of the full range of color temperature for plant life with almost no heat. The only major disadvantage is, they are usually very costly – and many cheaper alternatives are available that can do the job just as perfectly.

For most hydroponic gardens, different bulbs are combined to cover the full spectrum of blues and orange-reds that plants need for various stages of growth although leafy plants will lean more heavily toward the blues. Refer to your retailer for the best grow light combination that can address your needs.

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