Your grow light is probably the most important component of your setup if you are growing cannabis indoors.
There are many types of lights available and they can range from a hundred to several thousand. But the two most popular families are HID (High-Intensity Discharge) and LED (Light Emitting-Diodes)
Lets first start by saying that both lights have their pros and cons. It ultimately depends on the style of grower you are and the budget you have allowed for this.
LED Grow Lights
This is the most recent technology in grow lights and there are still many growers skeptical about them. This is mainly due to the early days of the technology. At the time, very un-efficient products entered the market and they were far from offering the results of the HID's.
Since then, the technology has tremendously improved and can seriously compete even surpass HID's on many points.
Here again, there are a LOT of them on the market and they are very popular so here are a couple of upsides and downsides of LED:
Safety: There are less risk of a malfunction that can cause a fire than HID Bulbs.
Ease of use:
Most LED's are plug and play and don't require various component.
You don't need to change a bulb ever and most products will last up to 3 years before degrading.
The diodes will emit around 50% less heat than HID's and much of this heat is generated in the circuit thus not radiated directly into your canopy. Depending on the model, most LED's will have a built-in cooling system as well, meaning you don't need extra climatization.
LED's can be equivalent to HID's but will draw less electricity from and reduce your utility bill. Additionally, the reduction in heat implicates less cooling equipment such as fans and climatization. This will reduce the overall energy consumption of your setup. It is now common to see similar yields with LED compared to their HID equivalent, but using around 40% less power.
Because the heat produced by LED is less important, you can often bring the light closer to your canopy. This will also help prevent the plant to stretch too much while trying to reach the light source which is common with HID grow lights. This makes an ideal option for people growing in tents or in low spaces.
LED grow lights have the advantage of having a lot of control over the light spectrum. Some lights will have features allowing you to customize your spectrum. Other lights will have a mode to emit either more "blue" (optimal for the vegetative stage as it stimulates leaf, resin, and terpene development). Either more "red" (optimal for the flowering stage, promotes stem and flower production)
Some lights such as white-light LED will offer a very complete spectrum that can cover both stages properly.
The spectrum customization available with some models allows for superior work on the terpenes, trichomes, and pigmentation. This is also true for white-light as it provides a more natural type of light.
The cost of LED's is usually higher than buying a ballast, reflector, and bulbs depending on the quality. This is even more accurate when going with a high-end LED. However, it's important to take into account the cost of replacing bulbs and electricity costs when making your decision.
There is an overload of companies offering all types of LED. Most of the time if they are very cheap the results will speak for themselves. Be careful and go with trusted companies who have proven to offer reliable and safe grow lights.
Many HID growers will blame LED for not penetrating enough through the canopy resulting in a smaller yield. Many LED companies will deny this.
Risk of light burns:
The heat emitted by the LED is significantly inferior compared to bulbs. Because of this, many growers will take their light to close to the canopy and burn/bleach their plant with too much light. Be careful and keep it at the recommended height which depends on the chosen model.
Very useful for the plant, the blue light can be very dangerous to the human eye. Make sure to wear protection glasses or turn off the light when working around the plants.
Most popular LED grow lights:
(Courtesy of KIND LED)
Sometimes called "Blurples" This kind of grow light inherited this name because of the bluish/purplish color it emits. It offers a mixed spectrum combining red and blue diodes. They are now widely available since there are several Chinese companies that manufacture them. They are the most affordable LED's so they make a great choice for beginners. Although they have earned a bad reputation, there are still many companies such as Viparspectra and Mars-Hydro who offer good and durable "Blurples" that can achieve good results for the price.
However, there are some high-end Mixed Spectrum LED which gives you the ability to control exactly your spectrum and adapt it to the specific needs of your plant. This is the case with Kind, Black Dog, and California Lightworks to name a few.
This type of LED is in the family of the "white-light full-spectrum" and offers great penetration as it emits a very concentrated and powerful light. Some companies such as Optic LEDhave perfectioned the use of COB to offer high-quality grow lights.
(Courtesy of Horticulture Lighting Group)
QB (Quantum Boards):
Also in the "white-light full-spectrum" family, Quantum Boards have a good reputation for being very efficient grow lights. They have been greatly popularized by Horticulture Lighting Groupbut other companies such as Mars-Hydroare now using QB's for their new models.
(Courtesy of Spectrum King)
As the names say, White-light Full-Spectrum LED's will emit a blend of all the colors resulting in a more or less white light that replicates sunlight giving your plant very close to natural conditions. Reputable companies like Spectrum King,The Green Sunshine Companyor Crecerhave interesting grow lights using this technology as well.
How to choose your LED?
Hobby & Low budget Grower:
If your objective is to have the most wattage for the price you can go with Blurples but It is important to make adequate researches before buying one. On the other hand, if you want to go with "white-light" on a budget there are some DIY Quantum Boards from Horticulture Lighting Groupor the TSW and SP series from Mars-Hydro.
Medical & High-budget Grower:
If you fall into this category, chances are you are looking for the best possible quality which ultimately will depend on your preferences. As listed above there are various good brands each have their pros and cons.
Commercial & Vertical Farming Growers:
This requires LED grow lights to have ETL and UL certification which is the case for all brands listed above.
HID Grow Lights
They stand for High-Intensity Discharge and they are the most proven and used grow lights of the previous decades. For this type of grow light, you will need a ballast to power your bulb. A reflector to direct the light downwards and a bulb. Here again, there are plenty of options depending on your style so here are a couple of things to consider when going with HID grow lights:
The cost of HID's is usually significantly lower than buying an LED. This is even more accurate when compared with a good quality LED. Yet, it's important to take into account the cost of replacing bulbs and electricity costs when making your decision.
HID grow lights are said to penetrate the canopy better than LED grow lights allowing the entire plant to develop optimally.
With all the previous experimentation done by growers in the past, HID grow lights are considered the kings of big yields.
Most growers look for cooler temperatures. But, there are some situations where growers will need to raise the temperature of their environment. This makes HID's a good option for them.
Widely available expertise:
The fact that HID grow lights have been used for so long also means there is a large number of growers who have perfectioned their craft using them. Some will say it is often easier to find answers to your questions and learn from other growers' mistakes and successes.
Some people will swear only by HID because it allows them to easily replace components that can be found for a few dollars. Especially with magnetic ballasts. So if you have good knowledge of electric components and know where to find cheap replacement pieces. This might be the best bang for your buck,
The risk of a malfunction that can cause a fire is more likely to happen with HID.
The components needed to use HID's can quicklyrequire a lot of manipulation for the installation. Some will go with already assembled fixtures but often you will need to choose and install your ballast, connect it to your reflector and carefully insert the bulb in the socket. If you have heat issues you will have to install an air-cooled ballast with proper ventilation setup.
Risk of plant burns:
The heat emitted by the HID is significantly superior to the LED, so be careful to keep the light at the recommended height to avoid burning your crop.
HID's will draw more electricity than LED's and increase your utility bill. Additionally, the heat produced often means more cooling equipment will be needed such as fans and climatization. This increases the overall energy consumption of your setup.
Because the heat produced by HID is more important, you will often need to bring the light higher. This will cause the plant to stretch while trying to reach the light source. This makes a difficult option for people growing in tents or in low spaces.
HID Grow lights are not as customizable in terms of the spectrum compared to LED. The most common practice is using an MH (Metal-Halide) bulb for the vegetative stage because it emits more "blue" and later switch to HPS (High-Pressure Sodium) for the flowering cycle to get more "red". There are also CMH (Ceramic Metal-Halide) bulbs that offer a hybrid solution you can use for both stages. Ultimately, the LED is the only technology that can be designed to meet specific light spectrums optimal for cannabis plants.
Most popular HID grow lights
(Courtesy of Growweedeasy.com)
This is undeniably the most popular option. MH (Metal-Halide) is a bulb that produces mainly blue light making it the best option for the vegetative stage. When ready to switch the light cycle and begin the flowering stage, it's important to change the bulb for an HPS (High-Pressure Sodium). This will emit a different spectrum and give the red your plant needs to optimally develop buds.
(Courtesy of Growweedeasy.com)
This option is very interesting if you are looking for a good in-between. CMH (Ceramic Metal-Halide) Bulbs are very effective and emit a different spectrum composed of a mix between red and blue. Depending on the bulb you go with it will either lean more toward red (3000K) or more towards blue (4200K). Both options can be used for the entire growth of the cannabis plant with good results.
(Courtesy of Agrolux)
This type of light can be either HPS/MH or CMH but as the name says it has two bulbs merged in one. For this reason, it emits a very strong light and has to be kept at a certain distance from the canopy to avoid burning the plants. It is not recommended for people with small vertical space.
How to choose your HID?
Hobby & Low budget Grower:
Going with the good old bulbs can be a good option for hobby growers especially if your budget is very low. As previously said, there are some good and affordable LED's but they will almost always be more expensive than their HID equivalent. The most popular example is the 1000W HPS/MH vs any other LED. You can find very cheap setups including bulbs, reflectors, and ballast that will cost you a fraction of the price for the equivalent in LED. Even with replacements and additional electricity costs, you will probably be able to save on the first cycles before catching up. In order to have the best prices, you will most likely have to assemble the different pieces together. The most critical component in this setup is the bulb. For reputable brands, we recommend Ushio or Hortilux.
Medical & Commercial Grower:
This is where the HID option becomes even more interesting! For people who have to cover large areas, going with a fixture will be way cheaper than good quality LED and the results are proven to be very good in quality but also quantity. The most common practice is going with a complete fixture. They are compact, powerful (especially Double-ended) and with the new generations, you can link them together and have all sorts of controllers to automate your grow. Some brands you might want to consider are Hortilux, Agrolux, Lightspeed, and P.L. Light Systems to name a few.
Related: HID vs LED Grow Lights Comparison - Which Is Best For Growing Weed?