A Beginners Guide To Hydroponic Lighting

Thomas Angas by Thomas Angas | Last Updated: April 3, 2020

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Today you’re going to learn everything you need to know about hydroponic lighting.

From the different systems used, the importance of light for your grow right through to some alternatives to the traditional options this is the complete guide to setting up your indoor lighting systems.

In fact, we like to think this lighting setup has been one of the main reasons our crops and plants have done so well in recent years.

This is a none technichal guide so if you’re not super technical (like me) you’ll hopefully love the simplicity.

Let’s get started!

a picture of hydroponic lighting system in use

Hydroponic Lighting 101

One of the biggest challenges with growing plants indoors is lighting. Outside the sun provides all the lighting that the plants need to grow, however, indoors plants aren’t able to access this lighting source even on the sunniest window ledge!

That means if you’re growing plants inside you’re going to need to bring the sun indoors.

However, it’s not as simple as just switching on a desk lamp next to your plants and forgetting about it, in fact getting the lighting right is one of the hardest parts of any hydroponic system.

Believe it or not, different lighting types can have very different effects on your plants, so before we look at lighting options for hydroponics we just need to understand a little more about light and how it’s measured (don’t worry this will be super easy to follow).

How Light Is Measured

There are a few different terms to get your head around when it comes to lighting that we’ll run through the two main ones now:


When we talk about lighting temperature we’re not talking about the heat that comes from the bulb rather how “warm” or “cold” the light is. The cooler ratings tend to be at the blue end of the spectrum while the warmer temperatures are more orange.


There are three lighting output metrics that you’ll need to understand when shopping for hydroponic lighting:

Watts – the Wattage of the light is the amount of energy it takes to produce a certain amount of light. The higher the wattage, the brighter the light, but also the more power it uses. The efficiency of this system was introduced using incandescent lamps.

Lumens – the Lumen output of a light referes to how bright the bulb is. For hydroponics it’s not something we need to worry too much about as plants require a different type of light output.

Nanometers (nm) – the nanometer output of a light refers to the amount of visible light that we can see which is typically 400 to 700 nm with the full spectrum ranging from 400 to 730nm.

The majority of grow lights produce lights in the 450 to 730nm range. These are the most crucial nm measures with one addition of 650 nm in the middle of the spectrum.

For your plants to photosynthesize they require light at the 450 nm and 650 nm levels. Your plants will then use the light between 650 nm and 730 nm to through the phytochrome pigment which allows them to flower.

This is why your plants need a light that can offer a full spectrum output.

Lighting Options For Hydroponics

So now you hopefully know a little bit more about light and how important it is for hydroponics it’s time to take a look at the three most popular options.

Fluorescent Lights

Fluorescent light bulbs have now been around for years and have been used with some success by growers. They are affordable to leave running and don’t produce much heat meaning that they can be located close to the top of the plants without risking the bulb burning the leaves.

The big downside to fluorescent lights is that output typically isn’t powerful enough to penetrate through thicker foliage meaning lower leaves are unable to soak up rays.

Checkout our guide to the best CFL grow lights.


HID’s (High-Intensity Discharge Lights) use a much larger bulb the fluorescent or LED bulbs. There are two main types of HID lights available:

Metal Halide – these produce light at the cooler end of the spectrum and are useful at the early end of the growing process.

High-Pressure Sodium – these lights produce a much warmer output and are well suited to use when plants reach the flowering stage.

The biggest issue with HID lights is that they economical as other forms of lighting and require additional equipment to run.

The oteher consideration is that HID bulbs typically lose 70% of their output after 10,000 hours of use which means they’ll typically last around 2 years before they need to be replaced. Tha said, most serious growers who use HID bulbs will be constantly monitoring their output to ensure they’re performing properly.

The final consideration is that you shoud ensure there’s a gap between the bulb and the top of your plants as they will burn the leaves.


LED has been around long enough now that it’s now a reliable lighting source to use in your grow. We like LED over other forms of light as it’s very economical to run, produces good light output (although you want to steer clear of cheap Chines bulbs), runs cool and doesn’t need any additional equipment to use.

They’re also incredibly long lasting and wont start to diminish their lighting output after 10,000 hours.

Alternative Options

There are a number of lighting alternatives available to use in your hydroponic system including: