Back to Articles

The Differences Between Various Types of Cannabis Lights

Updated November 24, 2022

One of the most important decisions when growing cannabis is finding the ideal grow lights. It can be quite overwhelming due to the variety of lights available. We'll break down the differences between the various types of grow lights on the market, so you can decide which ones to choose to create the perfect environment for your plants to thrive in.

Fluorescent Grow Lights

Just like the lights you're used to seeing at a big department store or doctor's office - fluorescent grow lights are available in a full range of sizes and shapes. They are popular for their efficiency and the fact that they offer pleasant lighting for the human eye. Their efficiency also means that they are suitable for indoor gardening and herb lights without requiring too much electricity.


Compact Fluorescent Lights are a variant of fluorescent grow lights. Initially designed to be a successor of the incandescent lightbulb, these lights have a curved or twisted tube and can be found in most hardware stores. They have a

The lamps use a tube that is curved or folded to fit into the spa

These are the ones with twists in them, and they are commonly found with regular light bulbs in most stores. They have an excellent spectrum of light for cannabis growth. Their compact size also makes them a reliable choice for tight grow spaces, like inside a cabinet.


Another type of fluorescent grow light is T5. These are also very common and among the most popular lights sold specifically for growing cannabis and other plants. This makes it easy to find at most home improvement or gardening stores.

In most cases, T5 lights will be part of a panel. They are also larger and wider than CFLs in most cases.

Advantages of Flourescent Lights

Overall, one of the biggest advantages of fluorescent lights is their affordability, both at the time of purchase and in terms of electricity consumption. They also offer a nice light spectrum for cannabis growth. The ease of finding fluorescent lights, including CFLs is also a plus, as is the range of wattages available. Growers can easily find everything from daylight to warm white with ease, offering light for the full growing process.

They work well in small spaces since you can safely place the lights just several inches from the plants. This ability to put fluorescent lights close to plants also makes them ideal for young plants, clones, and seedlings as there is less wasted light.

Disadvantages of Flourescent Lights

One of the biggest disadvantages to fluorescent grow lights is that you will get smaller yields for every watt than with other grow lights, assuming you use them during the flowering stage. There is also the issue that fluorescent lamps’ light will not penetrate as far into the plant. As such, they are best for small, flat plants, not those in the flowering stage.

Fluorescent lights also tend to work best for smaller grows. In other words, they are a reasonable option if you only have a few plants, but if you have a lot of cannabis plants, they will become less useful.

High-intensity Discharge Grow Lights

High-intensity discharge (HID) grow lights are efficient and have large bulbs that are oddly-shaped. You typically attach an HID light into a hood or reflector that will reflect more of the light onto the plants. These lights are great for cannabis growth yet very hot compared to other types.

Metal Halide

Metal halide (MH) lights are a type of HID light that is best during the vegetative stage because of their bluish lights. You can, however, use them up through harvest.

High-pressure Sodium

High-pressure sodium (HPS) grow lights are among the most popular lights for the flowering stage. This comes from a combination of their efficiency and the ability of their yellow light to stimulate the production of buds. Using HPS lights during the flowering stage will give you the best yield per watt compared to every other grow light.

Ceramic Metal Halide or Light Emitting Ceramic

The terms ceramic metal halide (CMH) and light-emitting ceramic (LEC) refer to the same type of grow light, which is yet another HID light. The bulb uses ceramic in the lamp as high-pressure sodium does. This helps CMH lights achieve higher efficiency than MH lights, although HPS lights are still more efficient.


In terms of efficiency, HID lights will give you the best yield for every watt of power. HPS lights, in particular, are the most efficient during the flowering stage. Using HPS for this stage of cannabis growth can result in between 0.5 to 1 gram per watt.

Growers also appreciate the ability to hang HID lights the proper distance from plants easily. You do not have to adjust the lights as you would with fluorescent grow lights or guess to some extent like you would with LEDs.


The most significant disadvantage of HID bulbs is the large quantities of heat that they generate. The heat from HID grow lights is so concentrated that it almost always requires a hood and a cooling system. You need the cooling system to stop the heat from going straight to your plants or increasing the ambient temperature in your grow space. This head generation and the need for cooling becomes particularly vital when using HID lights with power over 250 watts.

Because of the heat produced by HID bulbs, there is also extra setup required. Specifically, you should very strongly consider using an exhaust fan that has ducting that vents out the heat.

There is also the issue that HID lights tend to have a few more parts to them than others. Most LED lights are just the light, and most fluorescents are just a fixture and bulb. By contrast, HIDs typically have the fixture, bulb, and an external ballast in addition to an extra cable. Then you add the exhaust systems on top of those requirements.

Using HID bulbs also tends to increase your electricity bills. Some of this comes from the fact that you need a ballast and hood instead of just using your regular light switch. Another aspect of the increased electricity bills is the need to put an exhaust system. You will need to power that system with more electricity.

LED Grow Lights

LED cool lights are a popular choice for growing cannabis as well. They frequently have built-in cooling functionality and run cooler, to begin with. You can also typically plug LED lights right into the wall then hang them up over the plants. This makes the setup very straightforward. Growers also like the high penetration of LED lights, which means you will not have to move them often. The high penetration is the opposite of that of fluorescents.

If you choose to use LED grow lights, ensure that they have some white or green light. Your cannabis plants will not grow as well without at least some of this light, as the lack can lead to nutrient deficiencies.

LED lights are available in options for everyone from beginners to experienced growers. This means that you can easily spend a large amount of money on LED grow lights initially, which is sometimes a disadvantage. However, those with large setups can recoup that money via electricity savings and the lack of exhaust required. There is also the option to buy more affordable LED grow lights.


One of the significant advantages of LED grow lights is that they feature built-in cooling, pushing the heat away and up from your plants. This means that the lights naturally run cooler, avoiding the need to put venting in your grow space. This is a particularly strong advantage compared to the heat generated by HID lights.

Growers also appreciate the small size of LEDs compared to other types of grow lights. The small size makes it possible to plug them in and get started, without having to fiddle with additional arrangements like fixtures or extra cables.

Many growers also feel that you get more resinous buds from LED grow lights. Other growers say that combining LEDs and HPS grow lights will give you amazing results. These advantages, however, still need more testing. The idea of superior results from LED grow lights is mostly based on anecdotal evidence so far.


Like the other types of cannabis grow lights, LEDs are not without their disadvantages. The fact that they run cooler than other types does not mean that they produce no heat. All lights will produce heat, and LEDs are no different. This means that if you have larger lights, such as those over 300 watts, you still may need to get a cooling or exhaust system. Otherwise, your grow space can become too warm.

On average, you will get a smaller yield from your LED grow light compared to HPS lights. The commonly accepted return for LEDs is about 0.5 gram per watt. Despite this, you can get more.

There is also a learning curve with LED lights due to the differences in the available grow lamps. So far, there are not any standards to follow and guide you. As such, you will have to spend time experimenting and practicing with LED grow lights so that you can boost your yields.

Some growers also dislike the fact that LED grow lights usually need plenty of space. The LED lights need to be separated from the plants. As such, you will need to have a taller grow space if you want to use LED lights and get good results. Even smaller LED panels need to be at least 18 inches from your plants during the flowering stage’s second half. Otherwise, you put your cannabis plants at risk of light burn. In the case of larger LED panels, this distance may increase to 30 inches. Many growers do not have enough space to accommodate this requirement.

Light Spectrums for Cannabis

As you shop for your cannabis lights, you will want to pay attention to the light spectrum included. The spectrum may be referenced via color or wavelengths, and different spectrums are ideal for each stage of the growing process.

Blue for Vegetative

During the vegetative stage of growth, your cannabis plants will do best with blue light, which is between 450 and 500 nanometers. It is common to use CFLs or fluorescent lights that have blue spectrums for starting seedlings or rooting clones. When it comes to pre-flowering and growth, you may want to opt for a similar spectrum but increased power. That change encourages the plant structures to get hardier, helping with future flowering. Metal halide lamps are common during this stage.

Red for Flowering

During the flowering stage, cannabis plants thrive with red light, between 610 and 750 nanometers. This light spectrum works best during this stage because it mimics autumn sunlight and autumn is typically when outdoor cannabis plants will flower. Many growers will use HPS lights during this stage. Increasingly, growers will use LED lights instead of or in addition to HPS lights.

Green Lights for Working

If you want to be able to work on your plants without the light affecting the cannabis plants, then look for green lights. The leaves will reflect most green light, meaning that it has almost no effect on your cannabis plants. That makes green lights an ideal choice for those times that you need to see what you are doing in your grow room but do not want to use a light that may influence your plants’ growth.

The Takeaway

Most grow lights for cannabis are fluorescent, LEDs, or HIDs, with HPS lights being the most popular type of HID light. Every type of light has its advantages and disadvantages, and some are better suited for specific stages of the growing process. Regardless of the kind of cannabis light you choose, you find yourself with hundreds of lighting products to choose from, both available online and at most home and garden stores. Just ensure that your cannabis plants get blue light during the vegetative stage and red during the flowering stage and be mindful of the heat produced by your lights.

Grow with us.

Get articles like this and cannabis seed deals.