Grow Guide: Choosing the Best Lights | Marijuana

Grow Guide: Choosing the Best Lights


Looking to upgrade your indoor grow to the next level? Or starting your first grow and overwhelmed with the amount of options? Today, I’m going to walk you through the illuminating world of grow lights. If you’re starting from scratch, check out our Guide to Starting Your Own Grow for all your equipment needs.

Light is an essential part of your grow, your plants won’t survive without it! As indoor growers in the 21st century, you have a wide range of options when it comes to lighting your grow. Different bulbs have various things to offer. It can be hard to chose just one type which is why many growers opt to checkerboard multiple types of lights through their room, creating a diverse spectrum. We, at, are going to guide you through all the possible options so you can find which light(s) are best for you, your plants and your space.   

grow-veg-tall-0791Plants stretching towards an air-cooled system of HPS lights. Photo courtesy of Allie Beckett


We’ll start with fluorescents because they are the most simple and cost effective option. 

If you’re new to growing, don’t want to put up a significant investment or have a small grow area – fluorescents are the light for you.


Veg operation using T-5 fluorescent lights. Photo courtesy of Allie Beckett

There are two types of fluorescents that will keep your plants full and healthy: Compact Fluorescent Lights (CFL) and Full Spectrum Fluorescent (T-5) lights.

CFLs are the go-to for closet growers. They give off the least amount of heat, they’re the most affordable, and you can place them close to your plants. They’re the coil-shaped bulbs you can find at any hardware store. CFLs also come in multiple spectrums, warm and cool (which we’ll dive into later). You’ll want to use a reflector attachment (which you can buy or make yourself) so that light is reflected and distributed evenly back onto the plants. CFLs won’t break the bank on the electricity bill but they’re not efficient enough to sustain a large, professional operation.

T-5s are fluorescents made for more industrial usage. They are lightweight, compact, don’t require exhaust and they provide both blue and red spectrums. T-5s triple the light output of normal fluorescents without increasing wattage. T-5s are great for vegging in commercial operations because they don’t create a lot of heat and the plants can tolerate them being very close so you can stack them on shelves to increase your square footage (example below). T-5s are also great for beginners to use throughout both the vegging and flowering cycles because they contain both red and blue spectrums. They’re also appealing to beginners because they’re affordable and don’t require any additional equipment such as air-cooled hoods or ballasts.


Example of a double-stacked veg operation using T-5s. Photo courtesy of Allie Beckett.

Fluorescents Overview

  • Low temperature
  • Affordable
  • Easy to install
  • Portable
  • Lightweight
  • Can be placed close to your plants
  • Different light spectrums available
  • Can be used for seedlings, clones and young plants
  • Low electricity (but not the most efficient)
  • Good for small gardens




Example of a grow using both Metal Halide and High-Pressure Sodium bulbs. Photo courtesy of Allie Beckett.

High-intensity discharge lights, also known as HID, are the go-to for large-scale grow operations. There is a larger initial investment but they will produce higher yields and are more energy efficient – one 400-watt HID light emits as much light as 800 watts of fluorescent tubing. But with HID’s more equipment is required to cool them down, whereas you can easily hang fluorescents in your closet without risk of overheating.

There are two types of HID Lights: Metal Halide and High-Pressure Sodium.

Metal Halides (MH) emit a white light that is strongest at the blue end of the spectrum. The blue spectrum imitates the spring/summer seasons and also has increased UV. These lights are traditionally used for vegetative growth because they promote both leaf and cell wall growth. The white light makes it easy for the human eye to spot any nutrient deficiencies that would show through your plant’s fan leaves.

High-Pressure Sodium (HPS) bulbs are the industry standard for your plant’s flowering stage. They emit a bright yellow light at the red end of the spectrum, simulating the fall/winter seasons, which promotes a more dense flower structure.  

Most growers’ preference is a mixture of both MH and HPS lights, but if you have to choose one, HPS is the way to go. MH bulbs will increase the amount of available UV light, but don’t create as vigorous of a stretch and fattening period.  The cannabis plant spends most of her time and energy flowering and creating the buds that we eventually smoke, so we want to give her the spectrum of light that best compliments the bloom phase.


Example of a grow using both types of HID lights: Metal Halide and High-Pressure Sodium. Photo courtesy of Allie Beckett.

High-Intensity Discharge Lights (HID) Overview

  • Intense, bright light
  • Runs hot and loud – Requires an exhaust system
  • Draws attention (from neighbors and power companies)
  • Produces high yields
  • High electricity bill
  • Stimulates fast growth
  • Good for large gardens
  • Double-ended option for increased lumens/par. (Gavitas)
  • Metal Halide (MH)
    • Blue Spectrum (Spring/Summer)
    • Vegetative Stage
    • Ripening Stage
    • Bulb replaced every 12 months
  • High-Pressure Sodium (HPS)
    •  Red Spectrum (Fall/Winter)
    • Flowering Stage
    • Bulb replaced every 12 months


Light-Emitting Diodes – LEDs ($$$)


Example of an all-LED grow operation. Photo courtesy of Allie Beckett.

LEDs attract many indoor and greenhouse growers because they are one of the most energy efficient options on the market, conserving up to 75% energy. They are self-contained, no need for additional ballasts or exhaust systems, and they are also very easy to set up. LED technology is still new to the agricultural world but frequent advancements have been made over the last 5 years. Some believe that LEDs increase trichome/resin production during the flowering cycle. However, others have seen this increased resin come with the price of a decrease in yield (after using only LED lights). Each diode creates a specific frequency, which in the past have been focused in the 400 (blue) and 600 (red) range of the spectrum.  Now, diodes are being focused on a wider range of frequencies, including UV. This combination of red and blue diodes is what makes LED light appear purple. The limited spectrum of LED fixtures over the last 5 years have compromised the yield most HID growers are used to, but advances are in the field are beginning to make the LED compete on comparable level with HID.


Cannabis flowering under LED lights. Photo courtesy of Allie Beckett.

LEDs Overview

  • Red, Blue and UV Spectrums
  • No additional equipment needed
  • Small, compact size
  • Long-lasting
  • Low temperature
  • Portable
  • Easy to install
  • Energy Efficient
  • Fairly Expensive
  • Good option for greenhouses


Plasma ($$$$)


Example of a Plasma light. Courtesy of Iunu.

Plasma lights are considered the most advanced light on the market,hence the hefty price tag. The technology was initially discovered by Nikolas Tesla. Plasma lights are unique in their ability to use electromagnetic induction to create light that most closely resembles the sun. Iunu explains, “Plasma lights use radio waves to charge the electrons of the gases contained inside a quartz-crystal bulb. This technology allows IUNU to use a more stable, filament-less bulb and results in a more efficient transfer of power, minimizing wasted energy.” The biggest distinction between plasma lights is that they emit high levels of ultraviolet (UV) radiation, which is naturally produced by the sun and hard to create artificially.  The full light spectrum creates strong lateral branching during the vegetative process, and extra resinous plants during flowering.


  • Fullest Light Spectrum
  • Energy Efficient
  • Low Temperature
  • Expensive
  • New Technology


I hope this overview of grow light technology has enlightened you to the possibilities of customizing your own indoor grow. There are many ways to mix and match lights to find what fits the needs of your plants and your grow room. There is no right answer, so experiment away! I’d love to hear some of your findings in the comments below.


About Author

Allie is a NW-based content curator for and an organic farmer at TKO Reserve. She has been a professional in the marijuana industry since she was 18 years old, spending the first five years of her career working for Dope Magazine as lead photographer. Allie has worked on mainstream projects such as Idiot's Guide: Growing Marijuana, Branding Bud: The Consumerization of Cannabis and her own self-published book, As The Grass Grows.


  1. I would also mention ceramic metal halide lights. They are another form of HID lighting, but a CMH bulb basically combines the spectrum of HPS and MH. They are a metal halide bulb with much more red spectrum light. This means they are suitable for the entire grow cycle.

    CMH bulbs are not quite as powerful as HPS and thus not as effective at flowering, but the difference is not huge and more than made up for by their advantages: last much longer, run cooler, use less power and can be used for vegging.

  2. I have found the most interesting, turnkey, automated, liquid cooled LED grow light system. As far as I am aware this is the most energy efficient and powerful, 1000 watt lamps, system available anywhere. They MIT educated engineers started with a blank piece of “paper”, made a list of all of the things that would be wanted in a grow lighting system to serve the needs of the broadest range of users. What they came up with is “brilliant”.

    Rather than just using less energy with other than HPS lights, as most alternative lamps do, they incorporated liquid cooling into the boards to pull the heat of the growing spaces, saving far more energy than any other approach while kicking butt in the process.

    This has a very broad ranging spectral adjustment option, find the colors that work best for each strain, with faster turnovers, improved quality, trichome, oil and weight yields. The Cooling and Dehumidification system saves tons of money on cooling. The ROI on this systems is amazingly short.

  3. As I saw that many people are using the Viparspectra 600W to grow plants indoor. I don’t know if this is right, but saw lots of people saying that they get good results. You guys may try this.

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