Everyone's talking about them, but HID hydroponic light systems are still a mystery in many ways. Find out about the 5 types of HIDs used in hydroponic light systems today by reading the following article.

HID Hydroponic Light Systems Overview

A lot of people tend to believe that HID (High Intensity Discharge) lights were born and raised with hydroponic systems, but in truth they were being used long before hydroponics reached the level of popularity it basks in today.

High intensity discharge lights were commonly used in large areas such as warehouses, theaters, parking lots or amphitheaters, since they could easily cover such wide rooms with their level of intensity.

As soon as the hydroponic industry started growing in popularity, professional and amateur gardeners alike strived to bring the best conditions to their plants and lighting was a major concern, since sunlight was not always enough for plants growing in a greenhouse.

Hydroponic light systems were designed for maximum efficiency with a minimum amount of power and the HID technology proved to be a perfect fit in such a scenario.

I recommend you buy your lamps from a trusted hydroponics store that offers a large variety of lightning products, cheap to expensive.

There are currently 5 types of High Intensity Discharge lighting types and although the results are mostly the same from all five, the way they work differs quite a lot. You should also know that each lamp will have its own color temperature, which is important to some plants. But let's take a look at the 5 types of HIDs used in hydroponic light systems.

Mercury Vapor Hydroponic Light Systems

Mercury Vapor lamps use mercury in an excited state to produce intense light, in a process that is very similar to that used in high-pressure sodium lamps. Sometimes, mercury vapor lamps are coated with phosphorus to give the lamp a better, more intense temperature color than usual.

The normal color temperature for mercury vapor hydroponic lights has a bluish touch to it and it lacks any colors from the other end of the electromagnetic spectrum, namely the various versions of red and orange.

Most plants love to bathe in colors from both ends of the spectrum when it comes to hydroponic light requirements for growing, so phosphorus coatings are usually applied to "correct" these lamps for use in hydroponic gardening systems.

Pros

• good color rendition
• power efficient
• long lifetime

Cons

• no natural red, so a phosphorus coating needs to be applied for the full color spectrum
• ultraviolet hazard

Metal Halide Hydroponic Light Systems

Metal halide lamps are the older brothers of mercury vapor ones. In MH lamps, mercury still takes a large part of the inside of the bulb, but an amalgam of other components is used in conjunction.

An electric arc generates enough heat to stir up the mercury and metal halide content, creating light. In comparison to mercury vapor lamps, metal halide ones have a much more natural color , losing the bluish tinge that pure mercury lamps shone.

This is one of the biggest advantages of metal halide lamps and made them a lot more popular in hydroponics gardening systems, where light needs to be as natural as possible.

Pros

• good color temperature
• focused light means in can be used to cover a smaller area more intensely
• a lot of light can be produced from small lamps

Cons

• not very efficient
• if you want a larger area lit, there are better HIDs to tackle the job

High Pressure Sodium Hydroponic Light Systems

High Pressure Sodium (HPS) uses a combination of sodium and mercury to produce incredibly strong lights. As the mixture of sodium and mercury gets excited, an electrical arc heats it up, creating a light effect with a pinkish to orange tint.

Because HPS hydroponic lights focus on the red end of the electromagnetic spectrum, they are often used in conjunction with metal halide lamps (which are situated more to the blue end of the spectrum), in order to give the plants a full color bath.

Pros

• very efficient
• good color temperature spectrum
• smaller size compared to other HID lights

Cons

• takes some time to "warm up" every time it is started, time in which it shines a bright pink
• the high pressure working inside the light bulb makes it susceptible to explosions

Low Pressure Sodium Hydroponic Light Systems

You might think low pressure and high pressure sodium lamps are very similar, but in fact they have quite some major differences in between them. LPS lamps use a vacuum glass envelope that is coated with a layer of indium tin oxide, a material used to reflect and stop infrared rays. The light is allowed to go through this coated glass, but infrareds are stopped by the indium, so almost no amount of heat comes from a LPS lamp.

The color temperature of the light usually has a white or yellow tinge, which makes them a good choice for plants that need lighting as similar to sunlight as possible.

Pros

• LPS lamps don't lose their intensity as they increase in age, unlike other HIDs
• good efficiency
• no light pollution
• no heat

Cons

• lower intensity than the other 4 HID lamps
• the low pressure sodium lamps require a lot of space, since the more powerful they are, the longer their design
• monochromatic light that doesn't take advantage of the full electromagnetic spectrum

Xenon Hydroponic Lights

Xenon lamps aren't as popular as the other 4 HID lights, but they're also based on a newer technology that has room for improvement.

Basically, xenon lamps use ionized xenon gas in conjunction with an electric arc to create a powerful whitish light. The gas is maintained at an extremely high pressure (even higher than with sodium lamps), which also results in xenon lamps being the most powerful.

Pros

• low power consumption
• extremely good light intensity

Cons

• although a xenon lamp has low power consumption, it requires a sophisticated power supply
• extreme pressure inside the lamp may cause explosions that spread lamp parts with high velocities, causing damage and possibly injuries
• cannot be used on such a large scale as sodium, metal halide or mercury based lamps
• low lumen efficiency