HID vs. LED Grow Lights: What’s the Difference?

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Whether you’re a seasoned indoor grower or just getting started, you’ve probably heard about the battle between LED and HID grow lights. It’s a typical point of questioning among indoor gardeners who want to ensure that they get the best light for energy savings, higher yields, and healthy plants and flowers.

The numerous aspects of these grow lights include light intensity, light penetration, yield potential, energy efficiency, overall pricing, and upfront cost. By the end of this article, you’ll better understand the many options and know which type of light is best for you.

It’s also okay if you don’t want to go into too much detail about it. We will include a basic explanation of which choice we recommend in the majority of instances.

Before Reading Further

The discussion about HID and LED lighting is still raging, and both sides have valid arguments. We’ll try to sort through some of the facts presented by both sides in this post and offer you the tools you need to choose the best lights and increase the productivity of your indoor garden. We’ll update this article if and when further data or technology becomes available.

Help us grow! This post contains affiliate links, which means we receive a commission if you click a link and purchase something recommended. All opinions, however, are our own, and we do not accept payments for positive reviews.

HID vs. LED Grow Lights: What’s the Difference?

The contemporary LED grow light is usually the more accessible option for most indoor growers than HIDs are. Plants benefit from the uniform distribution of red, blue, and green light emitted by LEDs (similar to natural sunlight). It can also produce larger plant yields while using less electricity and requiring fewer additional costs.

While HID bulbs are typically less expensive upfront, when you include the cost of the fixture, additional cooling charges, and ventilation, LEDs are the ideal option for beginners and the most cost-effective option over time.

There are a few outliers, and you may still find high-quality lights in the HID fixture camp–– many pros swear by them. However, in terms of performance and cost savings, an LED system is usually the best entry-level alternative.

Based on a study done by MIGRO in 2021, here are some of the top compact-LED grow lights on the market in terms of PAR light output per watt.

Of the options listed above, most are available on Amazon, so we’ve included a comparison chart below:

Unfortunately, MIGRO doesn’t sell on Amazon. But you can purchase from them on their site.

Grow Light Color Spectrums

We all know that plants need light to thrive, but have you ever considered how the hue of light influences plant growth?

The sun produces the whole visible light spectrum, including red, orange, yellow, green, blue, indigo, and violet: the full-spectrum or white light. Most indoor plants flourish in full-spectrum bulbs, which produce a balance of cool and warm brightness that simulates (or at least tries to mirror) the sun. Seedlings, houseplants, culinary herbs, and several other plants thrive in them.

Blue light, in general, promotes the development of leaves and stems. Red light promotes flower development, making it crucial for fruit-bearing plants. However, there’s plenty of information available on the unique advantages of red and blue lights–– though some of it’s confusing.

A good video on frequent misunderstandings about the color spectrum, notably red and blue light, can be found below:

https://www.youtube.com/watch?v=NMVP7Nvew0A

PAR vs. Lumens

While it may seem self-evident, it’s easy to overlook the fact that plants and humans receive light in quite different ways. Humans use photopic vision to sense color. Photosynthetic active radiation (PAR) is the light wavelengths that drive photosynthesis in plants. Here’s a helpful article on the differences between PAR and lumens.

PAR refers to the wavelengths of light that encourage plant growth (Photosynthetic Active Radiation). We utilize Photosynthetic Photon Flux (PPF) to calculate the amount of PAR produced by a system per second. PPF does not indicate how much of the measured light reaches the plants, but it’s essential to know if you want to determine how efficiently a lighting system produces PAR.

The Photosynthetic Photon Flux Density is used to measure the quantity of PAR that travels from your fixture to your plants (PPFD). PPFD is a measurement of the PAR emitted by the lighting fixture at the plant.

To add to the challenge, you’ll need to average many PPFD readings taken over time since grow lights are usually most potent in the center, with light decreasing as you move away from the center. A grow light manufacturer may (and probably will) only supply the PPFD from the central space. “To ensure you are getting actual PPFD values over a specific growing region, the manufacturer must disclose the following: measurement distance from the light source (vertical and horizontal), number of measurements included in the average, and the min/max ratio” according to a Fluence post.

Grow Light Intensity

PPF (Photosynthetic Photon Flux) refers to the total amount of light produced per second by an LED, HID, or other light sources. We refer to as the intensity of the grow light unit of measurement as micromoles per second (umol/s).

Light intensity refers to the power or amount of light generated by a specific lighting source. It’s a wavelength-weighted power measurement for light sources. The lighting source determines the light intensity, and there are high and low light intensity fixtures, lamps, and bulbs available.

Different light intensities serve other functions when it comes to indoor gardening. Young plants, for example, require less light than vegetative and blooming plants.

What are HID Grow Lights?

While HID technology is older than LEDs, it produces more and brighter light. HIDs are also available in double-ended versions, making more light and taking up less space than single-ended lights. Growers commonly use HIDs in large commercial greenhouses.

HIDs can only produce one color, unlike LEDs, which may change color based on the diodes used. The type of gas used determines the light spectrum produced by a bulb. You must physically adjust the bulb to transition from a vegetative or full-spectrum light to a bloom arrangement.

High-Intensity Discharge (HID)

HID is the abbreviation for High Intensity Discharge lights. Inside HID bulbs are gas-filled tubes with electrodes on both ends. Electricity jumps from one electrode to the next, causing the gas to react and produce light.

HID grow lights are also available in a variety of styles. The two most prevalent types are metal halide (MH) and high pressure sodium light (HPS). Growers combine MH and HPS lamps and bulbs to achieve the spectrum required for each growth stage.

Metal Halide lights emit a blueish spectrum of light that’s ideal for the vegetative stage. Ceramic Metal Halide lights, a subtype of MH lights, provide a broad range that better mimics natural sunshine than any other type of grow light. Because of their yellowish-orange color, high-pressure sodium lights are suitable for blooming plants and acceptable for vegetative plants.

What are LED Grow Lights?

More than a century ago, Henry Josef Round invented the first light emitting diode (LED). However, innovators only first used red LEDs in commercial electronic devices such as TV signal lights and remote controls in the 1960s.

Since the 1990s, LEDs have evolved significantly, now considered as potential alternatives to traditional greenhouse lighting sources. It wasn’t until recently that researchers could increase the emission power of LEDs and make them emit white light (full-spectrum light).

Traditional incandescent lamps use more energy and produce far more heat than this new LED type. LEDs are likewise built entirely of solid parts and can be made relatively compact. They may also be modified in many situations, allowing you to emit any color of visible light on the spectrum. You can alter the range to better match the needs of your plants.

Light-Emitting Diodes (LED)

LED stands for light-emitting diode. LED grow lights are energy-efficient luminaires that produce light for growing plants. These lights combine two semiconductor materials: one charged positively (protons) and one charged negatively (electrons). When protons and electrons collide, the energy projects as a photon that determines the light’s hue. The light is then focused and emitted in a precise direction.

Here’s a quick demonstration of how LED lighting works:

https://www.youtube.com/watch?v=BH9LI973H8w

HID vs. LED Grow Lights: Which is the Best?

Choosing the best type of light isn’t as easy as you may assume. Each type of light has its advantages and drawbacks. Let’s look at some of the critical distinctions between HID and LED grow lights. Hopefully, this information will help you determine which option is the ideal fit for your requirements.

HID Grow Lights: Pros & Cons

Pros: 

History

Since HID lights have been the industry standard for so many decades, there is widely available expertise to match usage. There is little we can’t know about HIDs (if anything at all).

Lower Up-Front Cost

Another benefit of ubiquity is affordability. HIDs have been innovated and improved since their invention, so cost efficiency is at an all-time high. The components are simple enough to be cheap.

Higher Wattage

HID lights tend to have more concentrated power and a subsequent higher wattage per bulb. If you prefer power over precision, HID might be the way to go.

Full Plant Light Spectrum

An HID light supplies all the light you need, all at once. They’re not particularly heavy on red, blue, or yellow light but strike a balance regardless of your plants’ growth stage.

Higher Temperatures

With all the power HIDs offer, a high temperature follows closely. A lot of heat can be great for a large grow room that thrives on heat-fueled humidity or for plants from the desert. 

Better Coverage for Large Spaces

HID plant lights cover lots of space quickly. Large growing areas need relatively fewer HID bulbs because of their broad coverage.

Canopy Penetration & Full Nourishment

Power is the name of the game for HIDs, not only in light and heat but also in feeding your plants. The bright, broad spectrum of light will rip through the densest canopies for deep nourishment.

Larger Yields

Generally speaking, more is more. With all the juice an HID can offer, harvests are bound to reap the benefits. 

Simpler Pruning Process

Because the light from HIDs hits a plant more generally, you shouldn’t need to prune your gardens to optimize nourishment. No matter where they’re growing, if an HID is nearby, the plants will eat.

Better Consistency

They’re not sexy, but they get results. With fewer options for customization, you can be more consistently aware of what to expect each harvest season.

More Standardization

Since HIDs have been around longer and have a history of regulation by farmers, you can be pretty sure of the quality no matter what brand or variety you choose.  

Reliability

Although they require some upkeep and adaptability, HID grow-lights are far from fussy. The components themselves are not too complicated: a big, strong light bulb. You can count on HIDs to get the job done.

Customizability

The lights themselves may not have many variables, but an HID grow operation is far more than the bulbs, creating space for a lot of customization. From reflectors to cooling systems, stands, and aeration, you can fine-tune every part of your garden.

Repairability

As with much older light technology, there aren’t many intricate pieces too tough to figure out. If one part breaks, you can just as easily replace it. If one bulb pops, you’ve still got 90% of the system in working order.

Cons:

Expensive to Run

Among their main drawbacks, HID light systems lose affordability as time goes on. They require numerous pieces to complete the set, need periodic repairs, and need counteractive measures to offset their heat output.

Poor Energy-Efficiency

HID lights and lamps use a lot of energy; your wallet will feel it, and likely mother nature will too. You also need to consider air conditioning accommodation to regulate temperature, adding to the energy output.

Complexity

The science behind HIDs is simple, though the setup can get complicated. The lights aren’t exact, so they will likely require additional equipment and attention to optimize growth.

Requires More Equipment

From reflectors to cooling systems, a grow tent, stands, and aeration, you can fine-tune every part of your garden. However, more pieces can mean more problems.

Higher-Maintenance

HID lights are typically not a “set-it-and-forget-it” system. Throughout the growing process and different times of the year, lights will need to be adjusted, reflectors rearranged, and air conditioning increased.

Dim & Burn-Out More Quickly

Remember how quickly those old-school Edison bulbs can burn out? While not as bad, the technology is similar. Burning halogen bulbs just don’t last like modern fluorescents. But they might be prettier!

Long-Term Decay

Along with the bulbs, each piece will suffer from decay. Aluminum reflectors will dull over time, and cooling systems won’t last forever. As parts need to be adjusted, breakage is inevitable.

Environmentally Unsustainable Parts

The widespread use of traditional forms of lighting like HIDs has a significant detrimental impact on the environment, including our air, water, and soil. HID fixtures are among the most environmentally destructive lighting systems due to their power generation and disposal requirements for toxic metal components.

Light Spectrum – Imprecise Vegetative/Bloom Spectrums

HIDs will give a plant all the kinds of light it could ever need, all at once. That might sound great, but plants need different spectrums in different phases. Vegetative growth needs more blue light, whereas the blooming and flowering stage needs more red light (broadly speaking).

Fire Risk

HID lights get hot! So much power turns to heat quickly. Be cautious of fire risks, especially with dry plants. A strict watering schedule is imperative.

Risk of Plant Burns

Your garden might not catch on fire, but the intense light and heat from an HID setup can scorch delicate leaves and petals on whatever you’re growing. Make sure to regulate temperatures, water plants appropriately, and space the lights sufficiently.

Unideal for Small SetUps

If you just want some fresh basil for cooking, HIDs are way overkill. Unless you’re looking to start indoor urban farming, you can likely do without the high-powered HID system.

Height Limitation

HIDs can’t get too close to plants, or they’ll burn them up. So if you’re in a tight spot or your plants grow to the ceiling, you’ll likely have to find another light source for those final stages of growth.

LED Grow Lights: Pros & Cons

Pros: 

Precise Light Spectrum

LED grow lights contain several small bulbs, each of which can highlight an aspect of the light spectrum. No matter which grow cycle your plant is in, there’s an LED to feed it.

 

Energy Efficiency

If you’re looking to reduce your environmental impact (as you should be!), LEDs are a small but significant step. These lights can get bright without trying too hard.

 

PAR-Per-Watt Value

Energy efficiency benefits your wallet, too. Your energy bill shouldn’t increase much, and you won’t have to worry about offsetting an over productive system.

 

Bloom & Vegetation Modes

Many LED lights allow you to focus red light for blooming or blue light for vegetation, all in the same system. You can also shine a balance of the two, depending on your plants’ needs.

 

No Toxic Metals

Older light bulbs often use toxic or non-recyclable metals, but LEDs do not! You won’t have to worry about special disposal instructions should your lights ever stop working.

 

Long-Lasting Fixtures (Up to 100,000 Hours)

Some LED lights can last the equivalent of 11 years if left on all day, every day. That’s about 20 years of usage for regular growing schedules.

 

Lower-Maintenance – Durability

LEDs don’t break very often, and even if they do, they operate so that one damaged piece won’t render the rest obsolete. 

 

Sufficient for Any Size Set-Up

I’ve used one LED grow light for a tiny basil plant. I’ve used six lights for a complete indoor garden. No matter the size, LEDs can get the job done.

 

Great for Confined Spaces

If you’re growing in a tiny space or only want a small garden, LEDs can come in compact sizes to fit your unique needs. Don’t worry about your grow lights becoming the focal point of your home.

 

Heat & Fire Safety

LEDs give off comparatively less heat and pose a little-to-no threat of fire or overheating. Little heat and a lower temperature means you can leave these lights on safely for hours or days on end.

 

Various Form Factors – High Bay, Linear, etc.

When we say ‘LED,’ we could be referring to several shapes and sizes. Some look similar to hanging industrial lights, while others are sleek and cylindrical. You can even buy them as individual bulbs, allowing you to customize them almost endlessly.

 

Long-Term Affordability

LEDs may be a bit pricier upfront, but over time they are very cost-effective. Durability mixed with energy efficiency along with not needing much extra equipment allows for minimal upkeep costs.

 

Minimal Cooling Needs

One of those unnecessary upkeep costs is supplemental cooling. LEDs don’t give off much heat if you can even notice it at all. You shouldn’t have to think about keeping the AC running or circulating air through your garden using an LED.

 

Ease of Use

Most LED lights are an all-in-one package, meaning all you have to do is hang it up and press a button. Many are even automated to match your lighting needs based on timing and spectrum control.

 

Supplemental Light

Since LEDs can be a gentle form of artificial light when used sparingly, they can be a great option if you just need a little more light for your plants. Maybe your windowsill gets plenty of sunlight, but winter months are coming, so you could use a couple of extra hours of sun.

Cons:

 

Learning Curve – Not as Much Current History

LEDs are a relatively recent technology, so the literature isn’t as robust as other, older lighting systems. You may find that some experimentation is necessary to fine-tune your process.

 

Up-Front Cost

If you’re looking for the cheapest upfront option, an LED fixture might not be for you–– they can get pretty fancy, and the efficient technology comes at a cost.

 

Overwhelming Options

It seems like ‘LED’ is an overused descriptor for most lights these days, so it can be challenging to know which is appropriate for a garden. Even still, once you narrow it down, the specifications are countless. 

 

Variability

Since more and more producers are selling LEDs nowadays, quality can vary significantly. You might not always know how good of a purchase you’ve made until you test it out.

 

Light Spectrum

Some growers complain that LEDs don’t offer a broad enough light spectrum or focus too heavily on the blue and red ends. You’ll have to do some research to ensure your fixture is providing all the needed light.

 

Light Penetration

LEDs can be a bit more gentle than more traditional lighting methods, which may reduce the amount of light getting through to the base of your plants. The softer light might require multiple lights set from different angles.

 

Blue Light

LED lights tend to be blue/purple light heavy. However, some gardeners (and scientists) doubt the extent to which blue light is ideal for a plant. Many would suggest that a full-spectrum white light works just as well, if not better.

 

Height Limitation

Your LED lamp will need to remain close to the plants to absorb the nutrients they need. But if the light is too near the plant, it could damage the plants. Since plants are constantly growing toward a light source, you’ll need to adjust the light to be close but not touching.

 

Risk of Light Burn

If the LED light gets too close to a plant, it can burn the leaves and flowers. Even though LEDs are a more gentle light source, you’ll need to monitor their distance from the garden.

 

Advanced Pruning Techniques

Since you’ll likely need to position several LEDs around your garden to ensure sufficient nutrition, you may have plants growing in various directions. Varied growth directions will require some creative pruning to ensure each part receives enough light, especially considering how tough it can be to penetrate the canopy.

When to Use HID Grow Lights

You Want Better Light Penetration.

If you’re growing something super dense and hardy, and a lot of it, nothing quite beats the old-school HID grow-lights. Just blast it with heat and power and watch the yield multiply!

 

Upfront Costs are Prohibitive.

If you want to start gardening right away but don’t have the cash for a sophisticated setup, an HID bulb may be the best choice. You can DIY reflective and cooling systems for a budget-friendly hack. 

 

You Don’t Mind Changing Bulbs.

We listed changing the light bulbs as a downside above, but is changing a bulb all that difficult? If you like the full-spectrum option and don’t mind tweaking the set up a few times a year, there’s no reason to fear the HID.

 

You Want a Full Spectrum.

Some people swear by full-spectrum, full-time. Have you ever seen blue sunlight? It may be old-fashioned, but bright white light gets the job done.

 

Maximum Yield is a Must.

HIDs are like diesel trucks: what they lack in finesse, they make up for in power. Some plants don’t need anything more than as much food as possible, and an HID setup won’t disappoint. Massive yields are almost guaranteed.

When to Use LED Grow Lights:

 

Energy Efficiency is Important To You.

If HIDs are diesel trucks, LEDs are electric sedans. If environmental sustainability is front of mind (as it should be), an LED is the only option. Environmental consciousness might be the deal-breaker.

 

You Can Afford to Invest More.

If you’ve got a little extra cash to throw at your garden, go for an LED setup. Over time, the cost will even out anyway.

 

Adjusting Lights Isn’t a Big Deal.

We listed adjusting the light as a downside above, but is moving a lamp all that difficult? If you like the customization options and don’t mind tweaking the set up a few times a year, there’s no reason to fear the LED.

 

You Want to Experiment with Light Spectrums.

Maybe nature doesn’t grow a well as we do. Sometimes plants need just blue light, and sometimes they need just red. Other times they need everything they can get. LEDs are the simplest way to satisfy needy plants.

 

You Want to Start Right Away.

Once you’ve got your LED light, you’ve got everything you need. No reflectors or HVAC is required. You can start growing right now!

Consider Using LED & HID Grow Lights

Professional growers most commonly use HID lights. LED grow lights, on the other hand, continue to have a sizable market. Indeed, combining the two can help you enjoy the best of both worlds. LEDs are a great addition to regular HID fixtures as a great way to brighten up the room. They’ll assist in bringing extra light into your environment, particularly when used as under canopy lighting.

HID Grow Lights

 

MH/HPS

Metal Halide (MH) and High-Pressure Sodium (HPS) are the two most common types of HID lamps available today. Metal Halide MH bulbs provide a blueish spectrum of light, ideal for usage during the vegetative stage of a plant’s life cycle. High-pressure sodium HPS bulbs produce a yellow-gold tint that is ideal for flowering but can also aid in the vegetative stage.

 

CMH 

The ceramic metal halide lamps, which come under the HID umbrella, are worth noting. They create blue-spectrum lights that are ideal for vegetative growth. Overall, the spectrum of light produced by CMH is reasonably close to that of LEDs. Ceramic Metal Halide (CMH) grow lights are a subcategory of Metal Halides. Likewise, high-intensity discharge (HID) lights employ one or two special CMH bulbs, each rated at 315 watts. These lights produce an astonishing spectrum of light that more closely resembles natural sunshine than any other light we’ve discovered.

 

Double-Ended

Without a doubt, double-ended grow lights are the go-to choice for commercial growers. The light released is more robust and evenly dispersed. DE lights emit up to 30% more powerful light than single-ended lights, but the spectrum is also more optimal. They emit a more significant amount of infrared and ultraviolet light, too.

The Best HID Grow Lights

How to Choose an HID

Beginner

A full-spectrum kit with a built-in reflector hood will be more than sufficient if you’re just starting. It should run you right around $100.00. Start with something simple like herbs or an indoor tomato plant, leaving the light on for 12 to 16 hours daily.

 

Intermediate

For seasoned professionals, the next level is customization: multiple kits, growing stands, different bulbs for various growth phases, and a full reflective enclosure. You’ll be a self-sufficient farmer in no time.

 

Expert

The only way up from here is to integrate LED lights into the setup. You read that right: expert HID growers are also using LEDs! The spectrum variability, light intensity, and low temperatures are perfect companions to the HID workhorse.

LED Grow Lights

 

White Light Full Spectrum

All-white light contains light at all wavelengths, making it a true full-spectrum light. Unless they also include white diodes, “purple” LEDs typically only emit light at specific wavelengths. Full-spectrum white light spans the light spectrum from infrared to near-ultraviolet, or all wavelengths benefitting the plant. In particular, sunlight is considered full spectrum, so a lamp that can mimic the sun is a great option.

 

Mixed Spectrum

There is an even better blend of hues than the all-white spectrum: an all-white range featuring red and blue diodes, as well as UV and IR. Diverse spectrum LEDs contain around 25% Red and Blue Diodes and full spectrum 6500k White Diodes. The afternoon sun’s visual effect is a natural glowing form of light that brings out the color in your garden and feeds its hunger.

The Best LED Grow Lights

What works well for one individual might not work well for another. As a result, we’ve compiled a list of the top LED grow lights on the market, organized by use and price.

 

For this comparison, we used MIGRO data. If there’s any doubt about MIGRO’s objectivity, given that they market their systems, we might remember that their products are ranked 4th for best value by PAR production per dollar and 2nd for best value after three years.

 

Before taxes and shipping, the figure below compares the cost of the light to the PAR output (mols/sec useable PPF) split per dollar.

How to Choose an LED

 

Beginner

 

If you’re just starting, one full-spectrum light will be more than sufficient. It can be as cheap as $25.00 for a simple setup. Start with something easy like herbs, leaving the light on for 12 to 16 hours daily.

 

Intermediate

 

For seasoned professionals, the next level is customization: Blue and red lights, complete spectrum kits, automated timers, and adjustable stands. The options are almost limitless. You’ll be a self-sufficient farmer in no time.

 

Expert

 

The only way up from here is to integrate HID lights into the setup. You read that right: expert LED growers are also using HIDs! The blast of power, heat, and full-spectrum lighting is a perfect companion to the LED acrobat. 

 

Conclusion

 

Even though comparing the two is complex, LED lights have improved and gotten more economical over time. However, HID fixtures have remained around the same in terms of efficiency and quality. Regardless, both varieties are more than capable of producing a bountiful garden. Using the two together is easily the most obvious choice for high yields. With that said, while HID lamps are still widely utilized in many commercial growth systems, they will most certainly be phased out in the following years by more cost-effective LED alternatives. It seems inevitable that LEDs will soon be able to do everything an HID can do, but more and better. In the meantime, for most indoor hobby growers, the humble-yet-skillful LED is the most sensible choice, and your plants will be better for it.

If you need help hanging a new set of artificial lights, and happen to live in the Chicago area like us, consider calling Fix It People to take care of it for you!

Let's grow together!