Today's Gardener (todaysgardener.com) participates in the Amazon Services LLC Associates Program.
Since medical cannabis growing has become popular, cannabis growers have been faced with a lot of options in terms of which lighting to use for their grow rooms. Ordinary gardeners face the same problem.
And even though there are many lights to choose from, grow lights such as LED and HPS are becoming more and more popular.
So which one is better? Let’s find out in this HPS vs LED grow lights showdown.
What Are LED and HPS Grow Lights?
Before we make LED vs HPS comparison we need to take a look at both lights and explain how they function and what they provide the plants.
If you’re new to gardening or plant growth in general, then you must know that not all sources of light are the same and each type of light source produces a different effect on your plants.
Some factors determine which light is better than the other, such as area coverage, heat emission, energy consumption, light color, and so on.
So let’s take a look at the 2 most popular to grow light options – LED and HPS lights.
What Are LED Lights?
LED stands for light-emitting diode, and as the name suggests, they’re made out of diodes that glow up when current flows through them.
The color of the LED lights is determined by how much energy is needed for it to reach the semiconductor as well as the energy value of the photons in the diode.
With red, green, and blue LED lights you can get almost every color of the light spectrum by combining those 3 colors and also by making some light brighter and some dimmer.
Standard LED lights that appear white are actually a combination of red, green, and blue and have amazing brightness, and have almost 90% more efficient than incandescent lights.
Now, because LED lights are so popular, not just for gardening, but also for other lighting applications, they are the first choice for some gardeners as they are cheap and easy to find in almost any color.
Their effect on plant growth is also well known, but we’ll talk about that later because we now need to focus our attention on HPS lights.
What Are HPS Lights?
HPS stands for high-pressure sodium vapor and these lights use sodium to produce light which is typically around 589 nm in wavelength and the color of the light usually seems yellow, but they also come in other colors depending on the wavelength they emit.
Two types of lights use sodium vapor:
- LPS – low-pressure sodium lights which are most commonly yellow and are used for street lights, apart from other applications as well.
- HPS – these lights emit more colors of the light spectrum than LPS but their color rendering abilities are still no match to other sources of light.
So as you can see, HPS lights do come in various colors, but they aren’t the best light source out there.
They still are a popular choice because they can cover quite a large area because of how bright they are and their beam angle. Also, they are energy efficient and can last a long time.
But how do HPS light vs LED stand, and which are better for your indoor gardening grow light?
Benefits of LED Lights
Every light source has its benefits and because LED lights are such a common option for most gardeners it’s no wonder why they are so present in the grow light market.
But let’s see what are the benefits of using LED lights and how they compare to HPS lights so that you know which light source is best for your plants.
1. High Efficiency
In terms of kilowatts, LED lights produce more light than HPS lights as the diodes in LED lights are better at converting electric energy into light.
This doesn’t mean that LED lights use up more power, but rather, they use far less power than other light sources as they need less energy to produce light.
Plants need strong brightness intensity to be able to grow properly, and because LED lights emit high-intensity light, most plants will favor LED lights over HPS.
2. Heat Emission
LED lights don’t get as hot as other types of light because they don’t emit infrared wavelengths which produce heat.
The heat emission is a big deal for most gardeners because, in the summer months, you need to have an air-conditioning system so that your plants can not only get the oxygen they need but also to keep them cool from the outside environment.
If you use a grow light that emits a lot of heat, then your plants will start to wilt, so that’s another reason why LED lights make great grow lights.
LED lights last a long time. Some LED lights can last up to 50,000 hours or about 5.5 years, which is quite amazing compared to some other light sources, such as HPS which can last only half of that.
LED diodes are also made out of polymer which is more durable than glass and nothing will happen to them if you spray the bulbs with water.
They are also low-maintenance and if one diode dies, you can quickly replace it.
The size of LED grows lights can vary. But because LED lights come in all shapes and sizes, and even in strips, you can easily adjust them to your needs.
Your plants must get good light coverage, and with LED lights, everything is possible.
Of course, HPS lights have better light coverage, but LED lights do their job exceptionally well.
Unlike most light sources, you can set up your LED lights to emit less light by dimming them.
This is crucial as some plants don’t enjoy too much light, and instead of changing your whole lighting system, you can adjust the light intensity of LED lights by using special filters or arranging them in a way that light isn’t focused in just one spot.
Benefits of HPS Lights
Now that we know the benefits of LED lights, let’s see what HPS lights bring to the table. You would think that in this LED vs HPS showdown that LED lights are the clear winner, but there are some things HPS lights are just better at than LEDs.
HPS lights are mainly used to grow cannabis, and let’s see why our cannabis growers prefer HPS lights over LEDs.
HPS lights are a lot cheaper than LED lights and even HPS systems that are off a known brand won’t cost you as much as an LED system would.
HPS bulbs are also easy to replace and if one bulb dies, you can buy a new one and replace it, rather than replacing the whole light system.
These lights are also mass-produced literally forever so because they’re always present on the market, you can get them for quite a low price any time of the year.
2. Growth Effect
HPS lights are amazing for cannabis as they stimulate faster growth and denser buds, not to mention bigger yields of cannabis crops.
This all has to do with the type of light the HPS grow lights produce. HPS lights produce a yellowish light that’s just about right for cannabis as it stimulates flowering. Of course, blue LED lights also stimulate flowering, but HPS lights have better coverage.
HPS lights won’t recreate the full light spectrum, but for some plants, they’re amazing at making the flowers bloom faster and stimulating ripeness.
False advertising can be tricky when it comes to all sorts of things, and especially lighting because many lights that are marketed as having a specific voltage, may not actually be that powerful at all.
With HPS lights that’s not a problem as they’re pretty straightforward. If you have an HPS lamp that says it produces 600 watts, it’ll produce that amount regardless, and you can see if the amount of voltage the light is producing by how bright it is.
LED lamps can be misleading, but we’ll cover that as well.
HPS lights are great. After all, you can get them in a wide variety of voltage which is important because you need to know exactly how many watts of power you’ll need for your indoor grow room.
The standard voltage is around 200 watts, which is ideal for most grow rooms, but you can go even less with 150 watts, or more with 400 – 1000 watts.
Just know that 1000 watts are definitely an over-kill because so much heat is radiated that you might face wilting.
5. Beam Angle
As mentioned, HPS lights have amazing light coverage because the beam angle is easily adjusted so that all of your plants can get the same amount of light.
This is important because inconsistent lighting can cause some plants to grow slower than others and your crops will end up looking unsymmetrical.
HPS lights are also easier to adjust than other light sources so that’s why they’re still a viable option for many growers.
LED vs HPS Comparison
It’s time to settle the score and talk about which grow light type is better than the other and why.
Of course, you should take this with a grain of salt because different light types work for different plant species so it’s hard to say if there’s a lighting system that’s far superior to any other.
But let’s try to find out which one is better – HPS vs LED.
1. LED Lights Offer a Broader Light Spectrum
HPS lights do come in other color variations apart from yellow, but LED lights have far more colors of the light spectrum and you can easily combine them to get the color you want.
And because red and blue are the best colors for stimulating plant growth, LED lights to do a far better job than HPS lights in making sure your plants get the best light source.
This round goes to LED lights.
2. HPS Lights Have Better Coverage
You can cover more plants with HPS lights with the same voltage as LED lights. So not only are HPS lights more space-efficient, but they also produce consistent light much better than LEDs.
Of course, you can always arrange your LED lights to emit light equally across your grow room, but HPS lights do that without a problem.
This means that you’ll need 2 or more LED lights to cover the same area as 1 HPS light.
This round goes to HPS lights.
3. LED Lights Have Better Heat Emission
If this was an HID vs LED grow lights comparison, then the clear winner would be HID lights as they emit the least amount of heat out of any grow light types.
But since we’re comparing HPS and LED lights, it’s safe to say that LED lights take the cake because HPS lights emit far more heat.
So because LED lights don’t require you to have an AC system and HPS lights do, the round goes to LED lights.
4. Better Yield?
Which grow light makes for better yield? Well, in this LED vs HPS yield comparison, it’s not clear right off the bat which type of light is better for your crop growth.
Of course, LED lights have more colors of the light spectrum, but HPS lights are still an efficient light source, and for plants like cannabis, they’re simply the best.
So knowing this, we would say that this is a tie because it all comes down to light efficiency.
5. LED Lights Are More Energy Efficient
LED lights consume less energy and produce more light than HPS lights. And, if you would compare them kilowatt-to-kilowatt, the results would be the same.
But this doesn’t mean that HPS lights will necessarily make your electric bills higher, it’s just that LED lights are better at saving energy, and if you add less heat emission in the mix, they’re also more eco-friendly because they make a far less carbon footprint then HPS lights.
So this round also goes to LEDs.
The final comparison between LED and HPS lights will be in terms of price.
Of course, LED lights will consume less energy than HPS lights thus making sure you have fewer expenses, but HPS lights are much cheaper than LED lights.
And, knowing that you can have better coverage with one HDS light than you would with one LED light, HPS lights are truly cheaper than LED ones.
All in all, this all comes down to personal preference. You either get more LED lights that consume less energy, or one HPS light that does the same job as multiple LEDs.
As you can see, LED lights are clearly the winner and if you would compare LED vs HPS grow tests, LED lights do make your life easier and stimulate growth better for most plants than HPS lights.
That’s not to say that HPS lights aren’t a viable option, it’s just if you’re not planning to grow cannabis, you might want to stick with LED lights as they are quite easy to get a hold of and you can even make your own LED lights, which you can’t do with HPS lights.
Frequently Asked Questions
What Are The Best LED Grow Lights?
It depends on which species of plants you want to grow, but typically you want to use white or blue color light for faster growth. LED lights also come in different voltage and you need to try out and see for yourself what works best.
How Many Plants Can I Grow With a 300W LED Light?
Usually, with 300W you’ll be able to grow up to 6 plants but it depends on the size of the plants and because 300W light can cover up to 3ft and a plant needs about 1ft of space to grow, you need to do the math and see if this light size will fit your indoor grow room.
Can You Leave Grow Lights On 24 Hours a Day?
This is definitely not recommended by both most manufacturers and experienced gardeners as you can easily damage your plants because of so much light exposure. Like us, plants need some nighttime as well, so it’s recommended that you keep your grow lights on for just 8 to 12 hours a day.
Can I Replace a High-Pressure Sodium Bulb With LED?
It is possible to replace an HPS bulb with a lower-watt LED one but you need to do a specific adjustment to your lighting system. And, because LED grows lights are just a bit more expensive than the HPS lights, there’s no point in trying as you’re far better off with buying original LED grow lights.
We hope that you’ve learned the differences and benefits of LED and HPS lights so that you make the right choice when you’re stuck choosing one over the other.
In the end, it all comes down to your needs and personal preference, and we hope you get the best lighting for your plants.
Good luck and happy gardening!