Hydroponic lighting systems are one of the most important aspects of your hydroponic setup. Without the right lighting system, your plants won’t grow to their full potential. However, there are a lot of options and it’s hard to know what your plants will need without proper research.

This guide will help you understand hydroponic lighting systems so you can grow healthy, happy hydroponic plants!

Understanding Hydroponic Lighting

It’s common for people to start growing indoors because they don’t have enough space outdoors. But what do you do about lighting if your plants aren’t getting sunlight?

It’s important to pick out the correct kind of hydroponic lighting for your setup. But it can be a tall order considering how many options there are! It’s not as simple as just choosing one; different plants have different lighting needs.

Even more confusing, plants need a different amount of light when they’re indoors compared to when they’re outdoors. For example, plants that may need 6-8 hours of sunlight outside may need about 15 hours of light inside. 

In addition, perennials are more finicky when it comes to light requirements. Keep that in mind!

Most hydroponic growers use timers on their lights in order to ensure that no mistakes are made.

Different Hydroponic Crops Need Different Lighting

If you have a variety of different plants in your garden, lighting gets even trickier. In that case, it’s imperative to create a unique schedule of timed lights so that each of your crops gets what they need.

Let’s go over some different kinds of plants so you have a better idea of what this means.

  • Day-neutral plants. Day-neutral plants tend to be the least picky. They have a knack for producing fruit regardless of if they have the exactly correct light levels or not. A common example is eggplants.
  • Long-day plants. Long-day plants can require as much as 18 hours of light each day! Lettuce and potatoes are some examples. They require so much light to mimic summer days when they typically flower.
  • Short-day plants. Short-day plants need a lot of darkness in order to produce flowers. If they get more than 12 hours of light per day, they won’t flower. Strawberries are a good example of short-day plants. They need such little light because the light cycle needs to mimic the amount of light they’d get in the spring.

Types of hydroponic lighting

types of hydroponic lightening

Now that you know a bit about what different plants require, we can discuss different types of grow lights.

HPS – High-Pressure Sodium Bulbs

HPS mimics autumn light by having a red tint. They’re usually used during a plant’s flowering stage.

They’re the bulbs of choice for lots of hydroponic gardeners because they’re cheap and effective. 

Something to keep in mind is that they produce a lot of heat, so they must be kept higher up to avoid scorching your plants. The excess heat will also increase your energy bill.

Metal Halide Bulbs (MH)

MH put out a light blue light that’s great for vegetative growth. They’re pretty efficient and don’t produce much heat.

That being said, they’re one of your more expensive options and aren’t all that versatile.

HID Hydroponic Lights

HID lights produce a lot of heat, but they’re still one of the best artificial light options on the market. You can grow pretty much anything using HID lights.

LED Lighting

Although LED bulbs are well-known by most people, they’re actually pretty new when it comes to hydroponic gardening. Despite this, they’re an incredibly common type of hydroponic light source.

They’re expensive, to begin with, but have a high return on investment since they’re energy efficient and the bulbs can last for years rather than just one season. 

In addition, LEDs don’t emit much heat. This makes them a great option if you need your bulbs to be close to your plants because they won’t scorch your plants.

You can buy different LEDs depending on what spectrum of light you want to emit. Plants need different spectrums of light depending on what stage of growth they’re in (more on that later!).

In fact, you can even use the same LEDs for each stage of the plants’ lives by using filters!

Sulphur Plasma

Sulfur plasma lights are potentially the newest light development for hydroponics.

Their wattage ranges from 100w to 1300w. In other words, you can use the same lights for many different plants. 

They’re also energy efficient.

That being said, since they’re so new they cost a pretty penny and are hard to find.

Light spectrums

It’s important to understand light spectrums so you know what kind of light to provide to your plants. You’ll have to do some research into what your individual plants need, but it’s worth knowing the basics before doing so.

Green Spectrum

Chlorophyll doesn’t absorb green light as easily as it absorbs other wavelengths. Because of this, some people think the green spectrum isn’t all that important to plant growth.

However, green light is very important, especially in the lower leaves of the plant. 

When there’s a lot of light, there’s a point where plants can’t absorb any more red or blue light. But green light can still be absorbed deep within the leaves.

Red Spectrum

Red light is the best for stimulating photosynthesis and encouraging plant growth.

If you only grow your plants under red light, they’ll become tall with thin leaves. It’s important to balance your red light with the right amount of blue light to avoid this.

Grow Light Wattage

Grow light wattage refers to how much energy your lights are putting out. How many watts your plants need depends on your grow space size as well as the plants you’re growing.

For example, low light plants need anywhere between 11 and 18 watts per square foot. But this is only because they don’t require much light.

A general rule of thumb is that plants need about 32 watts per square foot of grow space.

Explaining Light Wavelengths

Light wavelengths are made of particles called photons. The photons travel in waves, and the length of the wave decides the color of the light. 

The visible light spectrum ranges from violet to red. However, the visible light spectrum is incredibly small in comparison to the entire light spectrum. 

Plants only use a portion of these wavelengths for photosynthesis. This range is between 400nm and 700nm. 

A typical incandescent light bulb emits a spectrum from about 300nm to 1400nm.

Grow lights such as LEDs let you control the spectrum they emit. This helps you target the specific wavelengths that are good for that part of your plant’s growth cycle. 

For example, blue light is great for leafy green plants while red light is good for stem growth.

Hydroponic lighting elements

Let’s go over some elements of hydroponic light systems.


The bulb refers to the kinds of lights we talked about earlier, such as LEDs, fluorescents, HIDs, and more.

Reflector hood

Reflector hoods are reflective casings surrounding the bulb. It helps increase how well the bulbs work by reflecting the light down to the plants so you don’t lose any peripherally.

They also aid you in using lights that don’t give off as much heat.

Remote ballast

Digital ballast is power boxes that power your lights. Sometimes they’re sold with the lights, but to get the highest quality remote ballast it’s best to purchase them separately. 

The remote ballast is actually the most expensive part of hydroponic light setups.

Be sure that your ballast matches your lights in wattage.


Your timer is the least expensive aspect of your system, but it’s absolutely vital. It should have a three-prong plug to ensure safety and effectiveness.

You can either get a manual timer or an electric timer. 


There’s a lot to know about hydroponic lighting systems. Thankfully, we’ve broken it down step-by-step so you know what to look for when growing your hydroponic plants.

Check out the rest of our blog for more how-to’s!