Growing plants indoors using a hydroponics garden generally requires a plant grow light since most houses have limited sunlight indoors. If you place the hydroponics garden by a window, it will only offer direct sunlight for part of the day while the sunlight shines through the window. If you choose to place the hydroponics garden without any exposure to the sunlight then you will definitely need some sort of grow light.
There are several plant grow lights to choose from and each one has its strengths and weaknesses. Even though there are three main types of hydroponics lights to choose from, there are only two types that are viable options for hydroponics. These are HID's and LED’s. So which one is better?
One of the most popular types of plant grow lights is the HID light, or High Intensity Discharge lamp. There are two main types of HID lamps that are common among the hydroponics crowd. These are the high pressure sodium lamp, and the metal halide lamp.
The reigning king for hydroponics lighting is the high pressure sodium light bulb, and it is one of the most popular types of grow lights among serious hydroponics gardeners. High pressure sodium provides the greatest light penetration and glows in the light spectrum most used by plants. This type of grow light produces a lot of light in the red and blue spectrum. Red is the main colors used by plants during flowering, while the blue spectrum is used for vegetative growth. The rest of the color spectrum is largely unused by the plants.
The main problem with the high pressure sodium bulb is that it produces a lot of heat and it doesn’t produce much in the blue light spectrum. The heat produced can dry out the leaves if you place the plant grow light to close to the plants. It can also raise the temperature in the grow area which could create other problems such as stopping the plants from growing. And of course it consumes a lot of electricity with some bulbs using up to a thousand kilowatts.
Metal halide is another form of HID lighting that is also common with hydroponics growing. Like the high pressure sodium bulb it produces a lot of light; however it doesn’t produce as many lumens as the high pressure sodium bulb, and it doesn’t produce as much red light. The metal halide bulb makes up for this shortcoming by producing more light in the blue spectrum then the high pressure sodium lamps which plants use for vegetative growth.
Some hydroponics growers use both HID’s to give their plants the most light in the spectrums that the plants use the most. Metal halide is used when the plants are in vegetative growth, and high pressure sodium is used when the plants are flowering. Some ballasts are even designed to handle both types of bulbs making the changeover as easy as changing a bulb instead of using two different ballasts.
Fluorescent lights are also used by the hydroponics gardeners, however they are not nearly as popular as the HID’s. Unlike HID lights, fluorescent lights don’t produce all the heat because they are more efficient at producing light. It is possible to buy fluorescent lights that glow in a variety of color spectrums giving you a variety of fluorescent tubes to choose from.
One of the biggest disadvantages with using fluorescent tubes is that they do not produce the light penetration that HID bulbs do. This means that they will need to be a lot closer to the plants to be effective. Another disadvantage with fluorescent tubes is that they don’t glow as bright as HID bulbs. Because of this, you will need to chain a lot of fluorescent tubes to produce the amount of light needed to grow plants. This is why fluorescent tubes are not that common for hydroponics.
LED’s, or Light Emitting Diodes, are fairly new to hydroponics and they are showing great promise. They have the advantage of being cool to the touch like fluorescent tubes, while being able to produce the light penetration of HID’s. Each LED bulb glows at a specific wavelength which means they only produce light in the spectrums that plants need.
Because of this, LED plant grow lights can be made to glow in the color spectrums that plants use the most. This is like using both the high pressure sodium and the metal halide lights at the same time. Most LED grow lights contain a mix of red and blue LED’s and maybe a few orange and white LED’s thrown into the mix.
Another advantage with LED’s is that they can glow very brightly; some of the bulbs are one to three watts in power. A light consisting of 100 one watt LED’s can produce the same amount of useable light that a 600 watt HID light produces.
The main disadvantage with LED’s is that the light is directional sort of like a flashlight. Because of this, they cover a smaller area then the other types of plant grow lights. LED lights are also more expensive than other light sources initially; however since they use so little electricity they pay for themselves in the long run.
So which one is better, HID or LED? Clearly the LED offers the best of both worlds since it uses such little electricity and heat while providing the colors that plants use with the intensity that they need. Even though it is still a new technology it is proving to be a great alternative to the HID’s.