Introduction to different types of grow lights

Cannabis growers and cultivators know by heart that proper lighting (e.g., sunlight) will result in good yield, high quality flowers, and successful growth of the plant. The most crucial factor is the correct selection of light that will supply a sufficient amount of heath and brightness that can mimic natural light brought about by sunlight. The proper lighting can greatly affect the yield and potency of each bud.

We all know that natural sunlight is optimal for the growth of cannabis plants. But for cannabis growers, they prefer to cultivate the cannabis plants indoors for many reasons. The first one is the location where they live in, not all weather conditions are fit to grow cannabis (e.g., winter). Second, there is much more control in the growth of the plant if the growing environment can be managed and controlled which is much more beneficial to the yield and potency of the plant.

You can obtain a lot of types of grow lights in the market that can be used for indoor cultivation. But, not all lights are created with the same performance as well as the cost. There will be differences when it comes to quality, heat production, and electricity consumption. Here are the types of grow lights for cannabis that will help you with your build.

Types of grow lights for cannabis 

CFL lights or fluorescent grow lights

CFL means compact fluorescent lights. These types of lights are available all over the market such as home depots, grocery stores, and growing equipment stores. These lights are suitable for small grow boxes at an affordable price.

Pros of CFLs

Since these are high demand types of lights, there is a lot of supply, there is no chance of not finding these. Also, these lights are compatible with any fixture since they are built with standard sockets. These are suitable for grow box builds that consume 40W or higher. These are available in varieties of color temperatures that are most beneficial at the vegetative stage of the cannabis plants as well as the flowering stage.

Cons of CFLs

The lighting output of these bulbs is low compared to high pressure sodiums (HPSs), metal halides (MH), and light emitting diodes (LEDs). As such, it is often suggested that CFLs are used for vegetative stages, particularly in the early phases, such as seed germination.

The CFL bulbs are not very efficient when it comes to electricity and they are not as powerful as other lights. But for beginners who are just starting to try growing their cannabis, these lights are a cost effective way to experiment.

High Intensity Discharge (HID) Grow Light Systems

Pros of HID

HIDs have long-been the industry standard for professional indoor growers. As such, they offer many benefits to home growers, too.

They’re More Consistent and Have Better Light Penetration

What yields more — HPSs, MHs, or LEDs? While you’ll find anecdotal evidence either way, the consensus points to HIDS (HPSs and MHs). LEDs are known for their incredible light intensity, but HIDs tend to have consistent quality light and better canopy penetration. More light can reach below your cannabis plants’ canopy, distributing light to the lower leaves and stems.

LEDs do not project well over long distances, and growers must adjust the lights as their cannabis plants grow to maintain the right overhead clearance for growth. The correct distance varies by model. In other words, the light intensity near the diodes is far greater than it is a foot or two away. The difference in intensity for an HID bulb is much less significant in general. With HIDs, cannabis plants get adequate light even when they’re farther away from the light source.

HIDs have also proven themselves to be reliable. They can increase plant yield and quality in your grow room. Besides the consistent light quality, HIDs are also more well established. Growers have more information about best practices, helping them get the most out of their crops.

They’re More Affordable Upfront

HIDs are a long-established technology available for an affordable price. Growers can often buy an entire HID lighting system, including the baffles, reflectors and bulbs, for less than the cost of a high-end, all-in-one LED system.

The lower upfront cost, combined with a higher yield per light, often makes these lights the superior option. Even when considering the lifetime operating costs, HIDs may still be kinder to your wallet.

They Provide Full-Spectrum Light

The goal of using artificial light is to replicate the natural sunlight cannabis plants would receive in nature. While adjusting the color temperature has its benefits, cannabis plants need all wavelengths to convert light into food. Consistent sunlight will always nourish your cannabis plants better than the same amount of artificial light.

HIDs offer full-spectrum light: MHs can provide blue light spectrum; HPSs can emit red light spectrum. Even full spectrum LEDs can’t replicate natural light quite as well as HIDs. Going further, ceramic metal halide (CMH) lights, another form of HID, are famous for their sunlight-like quality. Cannabis plants grown under full spectrum HIDs are guaranteed to receive all of the wavelengths required for growth because they have a complete light spectrum.

They’re More Standardized

The specifications from HID grow light manufacturers have more consistency than LEDs. When you buy an HID, you know what you’re getting, no matter the brand. HIDs are all used in similar ways and have established outputs and recommended distances to help you plan your grow room setup.

Cons of HID

While HIDs are popular for their high yields and healthier cannabis plants, they have some drawbacks, too. They might not be the right choice for every grow room.

They Are Less Energy-Efficient

While HID lights are cheaper initially, eventually, the added electricity cost could outweigh the cost advantage. Turning energy into light inside an HID tube is inherently less efficient. You lose energy through the chemical reaction and the ballast converter. Since they run hotter, they also raise your energy costs through more cooling and ventilation. HIDs also lose efficiency over their life span.

While these drawbacks are significant, modern HID bulbs have become more efficient. They cost more in electricity, but it will likely take a few years before the added costs catch up to the lower initial investment.

They Require More Maintenance

Working with HIDs makes some parts of your grow room more complicated. First, the lights will burn out sooner, and you’ll have to replace bulbs more often than LED fixtures. Since HIDs don’t have a customizable light spectrum, you must also physically change out bulbs to get blue or red light. Finally, with more components in an HID setup, you increase the risk of something breaking. The ballasts, light bulbs, external timers, and fans can all break down and require replacements.

The one area that doesn’t require more maintenance is adjusting the light height. As your cannabis plants grow, they’ll still receive consistent light from an HID. You’ll spend less time moving your lights up and down above your canopy. This is an area where it’s up to you to decide what type of maintenance you’d rather perform.

They Dim and Burn Out More Quickly

HIDs have a shorter life span than LEDs. Besides the added maintenance involved in switching out bulbs, you’ll also spend more money on replacements. Even before an HID bulb burns out, it will become dimmer. To maintain adequate light intensity for your cannabis plants, you’ll likely have to replace the lights sooner. In a small setup with just a few bulbs, you might not mind screwing in bulbs and occasionally eating the cost of a new one. However, in a more extensive setup, changing bulbs becomes a heavier workload.

They Produce More Heat

HIDs naturally produce heat since the gas inside the tube must be super-heated to create light. While HIDs are more efficient as they warm up, growers cannot take full advantage of the extra heat to improve energy efficiency. When you use HIDs, you must also use cooling fixtures to prevent your grow room from overheating. Not all growers will feel the effects of the extra heat the same way. Some setups need separate ventilation, and others can get away with a home air conditioning unit.

LED Grow Light Setup

LED lights specifically manufactured for cannabis growing have been increasing and growing in recent years. There is no kidding that the LED industry is about to take over. As LEDs become more and more advanced, their technology can now provide more lumens to provide the light needed by the plant without producing excessive heat that can damage the plant surface. However, not all LEDs are suitable for growing. So, you must choose the proper ones.

Pros of Light Emitting Diodes (LEDs)

Higher Efficiency

LEDs are far more efficient than HID lighting. Pound-for-pound — or rather kilowatt-for-kilowatt — they produce more light than HPS fixtures. The diodes of an LED fixture are inherently superior at converting electricity into light. That means you’ll have a lower electrical bill and you might not need as many fixtures to provide the same amount of light.

Along with better electrical efficiency comes better efficacy. A tailored LED spectrum provides cannabis plants with what they need for increased growth on a per-kilowatt basis. With an optimized spectrum and strong light intensity, cannabis plants yield more salable material, which fetches higher prices because of its enhanced quality.

LED’s lower electrical consumption reduces carbon emissions too. This environmental benefit has prompted many governments to offer a rebate credit for switching to LEDs, so check with your local jurisdiction.

Reduced HVAC Requirements

Because LEDs create much less heat than HPS, air-conditioning costs fall by as much as 30-40 percent when you make the switch. If you’re designing a facility from the ground up, your designer can specify a smaller HVAC system, thus lowering your capital expenditures. 

Unlike HPS, the LED spectrum does not contain infrared light. Infrared, which is radiant heat, increases leaf temperature. With a lower temperature at the leaves, you can run higher room temperatures for a significant savings in HVAC costs. Lower leaf temperatures can help mitigate pests and mold, too.

Longevity and Low Maintenance

Unlike HID, LEDs won’t need replacement every three or four crops, and they aren’t susceptible to breakage. HID bulbs are delicate, and as growers know, they need to be handled with the utmost care to avoid costly breakage. The possibility of breakage — and the resulting release of metallic gases such as mercury — may violate European Good Manufacturing Practices and other standards. If you want to properly dispose of these lamps, you’ll need to work with — and pay — a specialized recycling facilitator.

LEDs, on the other hand, have exceptional durability and runtimes. Once hanging, LED fixtures provide 50,000 hours of runtime and frequently go for ten years before needing replacement. IP-rated waterproof fixtures are easy to clean, and the individual diodes are encased in polymer — not glass — which makes them the most durable lighting solution available today. If your fixtures have an IP-67 rating, you can spray them with a hose between production cycles. 

Vertical Growing and Dimmability

Because LEDs have very little infrared in their spectrum, they can be hung close to the crop, which opens the door for vertical cultivation and lets you make the most of your square footage. Multiple LED light bars can be placed across the crop without the hotspot characteristic of HID technologies. And unlike HPS lights, LEDs are dimmable without a loss in efficiency, which means you can slowly increase your light intensity throughout the crop cycle while staying cost-effective.

Cons of LED

Higher Upfront Costs

Prospective buyers of LED lights may encounter sticker shock if they’re only familiar with HID lamps. The manufacturing processes and materials needed to create LED fixtures simply come at higher costs than those used for HID lamps. Despite lower lifetime costs, LED fixtures cost more than HPS upfront. For some growers, this makes LEDs a no-go, even though the longer runtimes and ease-of-use features payoff the investment several times over.

‍Light Spacing

Light from LEDs typically has a tight footprint similar to a spotlight. The beam angle of HPS lights, by comparison, is broad, which makes them easier to space in a greenhouse. Though the tight footprint of an LED light is great for narrow tables, overlapping the illumination area can be tricky, especially in greenhouses. Secondary optics (i.e., a lens plate over the diode array) can evenly distribute photons and ensure light uniformity over a broader area.

LED fixtures vary in terms of their beam angles, so it’s important to understand how they provide light for your cannabis plants. For large installations, make sure you work with an LED company that has a qualified lighting designer. 

‍Changes to the Dehumidification Plan 

Growing with LEDs is different. LED lights lower the cooling load in the grow room while increasing the dehumidifcation needs. That’s because the room is naturally cooler with LEDs, yet photosynthesis — and evapotranspiration — remain about the same. Plant’s still transpire because the stomata are open for CO2 exchange, and they still release moisture into the air.

Your first crop with LEDs may entail some unexpected humidity levels. Relative humidity increases as the temperature drops, so more dehumidification may be necessary. Make sure to keep an eye on your relative humidity and vapor pressure deficit throughout the crop cycle.

A Comparison of HID and LED Grow Lights and When to Use Each Type

Are LED grow lights better than HIDs? The truth is, it depends. With benefits and disadvantages to each, one grower’s best option may be different from the next. Many growers even combine LEDs and HIDs. Those who use several lighting types are more likely to rate themselves as very experienced and tend to grow more cannabis plants in their homes.

Using both in your grow house is a great way to get all the benefits your cannabis plants deserve and counteract some of the drawbacks. Some growers use different lights for each stage of growth. LEDs work best during the seedling and vegetative stages. The cooler lights are less likely to damage juveniles, and the 18 hours of light needed during vegetation are cheaper with an energy-efficient LED. HIDs become a better option during the flowering stage. The red wavelengths in HIDs better replicate fall sunlight, which is when cannabis plants naturally bloom.

Each lighting type can work well for specific scenarios. Rather than choosing a winner and a loser, it makes more sense to discuss when to use LED vs. HID grow lights.

When to Choose HID Grow Lights

You’ll probably prefer HIDs if:

  • You want better light penetration: HIDs are known for their reliability and light penetration. You’ll spend less time adjusting your lights.
  • Upfront costs are prohibitive: A quality HID is more affordable upfront. If you can’t spend a lot on your grow room right off the bat, an HID setup will help you get started without breaking the bank.
  • You don’t mind changing the bulbs: For a home grower with just a few cannabis plants, changing a bulb every so often doesn’t take much effort. If changing the bulbs doesn’t bother you, HIDs aren’t a lot of maintenance.
  • You want a full spectrum: A more complete light spectrum means healthier cannabis plants. If this is important to you, opt for CMH lights.
  • Maximum yield is a must for you: With HIDs, it’s possible to create larger cannabis plants. If you have limited space, HIDs can help you gain larger yields and maximize space efficiency.

When to Choose LED Grow Lights

You might prefer LED grow lights if:

  • Energy efficiency is important to you: Whether it’s to save money or save the planet, many home growers want to reduce their electricity consumption. Here, LED lights are the best choice.
  • You can afford to invest more: If you’re playing the long game and have more money to spend, go with LEDs. You’ll spend more now to save more down the road.
  • Adjusting the light isn’t a big deal: LEDs usually need to stay 6-18 inches above the canopy to maximize light penetration while avoiding light burn. If your schedule lets you check in on your cannabis plants often and move the lights as needed, you might not mind the frequent adjustments.
  • You want to experiment with light spectrums: Growers often enjoy customizing their light temperature and settings to find the right combination for their cannabis plants in each growth stage. If you work with lots of different plant species or strains or want to have the ability to easily tweak your light formula, LEDs are for you.
  • You want to plug and play: LED grow lights are an all-in-one system. Those who just want a simple way to grow cannabis plants at home will love that they can buy one fixture, plug it in and get planting.


Now that you have learned the pros and cons of the types of grow lights for cannabis, you can now decide what system you will use. That highly depends on the needs of your grow space or box. Also, this will be dictated by the budget that you have and the passion that you have for the industry.