Best 300 Watt LED Grow Light (True 300W!)

You may have noticed something.

All other sites with a list of the best 300 watt LED grow lights recommend a bunch of lights that are nowhere near 300 actual watts.

Worse, few of the lights they recommend even exist anymore.

And none are any good.

We decided to make a different list.

One that features lights that are currently on the market, that actually use 300 watts (or very close to it) and that can actually flower cannabis.

Keep reading to learn which is the best 300 watt LED grow light on the market.

We made sure to include several different types of lights, so you can find a good one no matter which type you prefer.

 

Best 300W LED Grow Lights Compared

05/30/2023 11:19 am GMT

 

Best 300W LED Grow Lights Reviewed

Our top choice is a bar style light, which is now the preferred style among growers. It is the newest innovation in the industry. We also included quantum board lights, which were the previously favored lights and are very similar to bar lights, and one COB fixture.

In general, we recommend bar lights or quantum lights. Both work equally well and which you prefer is a matter of preference. COB LEDs give you much deeper canopy penetration, but at the cost of an even light spread.

COBs delver much more intensity in the center of the coverage area than around the outside. As a result, we recommend COBs when you have a single plant beneath the light, or a single row of plants. If you have a more even canopy, you’ll be better off with the more even coverage of a bar or quantum board light.

 

Best Overall: Spider Farmer SE3000 LED Grow Light

My highest rated light is the SE3000 from Spider Farmer. The main reason for the high rating is that it gives you the best value for your money. You are getting a bar style light that is basically the same as the top brands, but paying less than half the price.

The same is true for all of Spider Farmer’s lights, which is why they are our favorite among the Chinese brands. Sure, they cost a bit more than the absolute cheapest, but their light use top-of-the-line components and their quality control and customer service are much better, too.

The SE3000 consumes 300 watts and is more or less equivalent to a 600 watt HID light. Spider Farmer uses the top-of-the-line Samsung LM301B chips on these lights.

These are the most efficient chips on the market and deliver 2.75 umol per joule. This means more light output for each watt of electricity you input.

The biggest advantage of these bar style lights is that they give you a much more even light spread. Even plants around the outside of the coverage area still get plenty of light and the difference between the center and the corners is much smaller than with other fixtures.

Sure, those other types of lights get much higher PPFD (often wrongly called PAR) readings in the center, which manufacturers use to try to make their lights seem better. But it is the overall output that is important, not the output dead center.

When you look at the PPFD chart for this light you’ll notice a reading of around 1200 umol/m²/s in the center and of nearly 500 umol/m²/s in the corners. That is a much smaller difference than other types of lights.

The other big advantage is in heat dissipation. These lights give off the same amount of heat as other types (of course, they have to physically), but the spaces between the bars mean the heat dissipates better and the fixture does not even need any fans to keep the chips cool enough to maximize their effective lifespan.

You can reduce the overall heat output somewhat by detaching the driver and placing it outside your grow tent. The driver is also dimmable, so you can reduce power consumption when you don’t need the full output of the light, for example during vegging.

You can daisy chain up to 30 of these fixtures together. Even better, you can dim them all together as one. That is a newer innovation in these bar lights that makes things so much easier.

Spider Farmer includes a hanging kit and adjustable ratchet hangers with each light. As they should. Any good brand does that these days. What’s different here is a 5 year warranty, where most brands give you a maximum of 3. You also get 30 days to return the light.

 

Best 300W Quantum Board LED: HLG 300L RSpec

Before the bar style lights took over the industry, quantum lights were all the rage. Actually, they are still hugely popular. And they are basically the same as the bar lights. They use the same chips and drivers and have the same light spreads.

The main difference is the gaps between the bars, instead of having a solid panel. However, the practical differences, in terms of results, are virtually nonexistent.

And when it comes to quantum board lights, Horticulture Lighting Group, HLG for short, is the brand that pioneered them. They created the first ones and came up with the name “quantum board”. Every other brand soon copied them.

HLG still makes the best quantum boards, since they have continued to improve on their original design, using newer chips and updating the spectrum.

The prices have come down, too. Their lights now only cost slightly more than the top Chinese competitors (like Spider Farmer) and far less than competing American made LED grow lights (HLG themselves make all of their lights in Tennessee).

In short, HLG is the best LED grow light manufacturer out there at the moment. We feel you get a slightly better value from Spider Farmer, but it’s very close. Both brands lead the way.

The 300L RSpec is a flowering light, but it works incredibly well for vegging, too. If you are going to use the light for all stages, this is the one to get. If you want to use separate lights, get this one for flowering and the BSpec version (see below) for vegging.

The RSpec has a very similar spectrum to the Spider Farmer above, minus the UV and IR light. HLG’s philosophy is that not everyone wants UV, so it is better to just add it separately as supplemental lighting.

You really don’t want UV light all day anyway. Just a few hours is idea. You also don’t necessarily want it throughout the entire grow. It is most effective toward the end of flowering.

HLG actually offer a small UV bar light that you can attach to their larger fixtures. If you want UV, this is the best way to go. Better than a LED grow light that emits UV all day long. That said, you can also just buy a UV reptile bulb and save a ton of money. There is a reason LED grow lights are not good for reptile use.

The 300L RSpec uses 270 watts (so not quite 300) and is dimmable down to 90, for when you don’t need full power and want to save on electricity.

The fixture uses Samsung LM301H diodes, which are slightly less efficient than the 301B diodes used by Spider Farmer. The other main difference, apart from being a quantum board light and not a bar light, is the form factor.

The 300L is rectangular, which means it has a rectangular coverage area of 2 x 4 feet. That said, it also works great in a 3 x 3 foot tent. For vegging, the effective coverage area increases to 4 x 4. Of course, you can just dim the light a bit and use it to veg the same size area as flowering.

The overall output is 700 umol/s, which is great for a 270 watt input. That works out to an efficiency of 2.6 umol per joule, so slightly behind the Spider Farmer fixture above.

HLG also ship their lights with hanging equipment, but hey only warranty them for 3 years (which is standard in the industry). We prefer the Spider Farmer at 300 watts, but if you have a rectangular grow space this one makes more sense. The same goes if you prefer quantum lights to bar lights.

 

Best Budget 300 Watt LED Grow Light: Mars Hydro TSW2000

The Mars Hydro TSW2000 is our top choice for the best budget 300 watt LED grow light, but it gets that title by default. Don’t get me wrong, this is a great light. But when it comes t budget HLG alternatives, Mars Hydro is not our favorite.

For budget quantum boards, we prefer Spider Farmer (review here). Viparspectra (review here) comes in second, with Mars Hydro just behind them. The three are all pretty close, but we simply prefer Spider Farmer as a company, and Viparspectra second.If you’re curious, we have an article that compares Mars Hydro vs Spider Farmer in more detail.

However, neither of those brands makes a 300 watt quantum board light. This leaves the best budget light title open for Mars Hydro with their 300 watt TSW2000. It is essentially equivalent to about 500 HID watts.

This light uses Epistar diodes, which is why the price is a bit lower. Epistar is good, but it is not Samsung. The efficiency shows this, with this light achieving around 2.6 umol per joule. That is still incredible and on par with the HLG lights, but it falls behind Spider Farmer and the top Viparspectra series of lights.

This light has a similar spectrum to those other two brands, with a mix of 3000k and 5000K white light, 660 nm deep red, and 760 nm infrared. This is a great spectrum for all stages, but especially for bloom.

The Mars fixture is also dimmable and daisy chainable. You can connect up to 30 lights. One thing that is different between these Mars fixtures and all other quantum style lights are the reflectors around the side.

I’m not sure if these reflectors are actually effective, but no other lights have them. If that is a feature you want, you can only find it i Mars Hydro’s TS series.

The TS fixtures ship with hangers and adjustable rope ratchets. Mars warranties these lights for 5 years.

 

Best 300W Veg Specialist: HLG 300L BSpec

The Horticulture Lighting Group 300L BSpec is basically the same as the RSpec above, with one major difference. It has a spectrum specifically tailored for the vegetative stage of plant growth.

As such, this is the fixture to get if you are planning to use it for vegging only, or if you are growing plants that do not flower, like herbs or succulents.

Specifically, this light uses the same white Samsung LM301H diodes, but with added 470 nm blue, instead of red. This is what makes them more suitable for vegging and they get the same 4 x 4 foot vegging footprint as the RSpec.

Everything else about the 300L BSpec is basically the same as the RSpec. The specs change slightly, due to the blue instead of red diodes. The power usage is 250 watts, dimmable to 30.

The output is 675 umol/s, with an efficiency of 2.5 umol per joule. Otherwise, it is exactly the same light, with supplemental blue diodes instead of supplemental red. If you need a 300 watt vegging specialist, this is by far your best option.

 

Best 300 Watt COB LED: Rapid LED CXB3590 2 x 4 Foot Fixture

We wanted to include one COB fixture, but had a hard time finding one that uses 300 watts. Our favorite budget COB brand Phlizon (review here) does not have any fixtures around 300 watts, so you would have to go up or down a bit.

That said, the Rapid LED COB fixtures are actually the best on the market. It’s just that they also cost quite a bit more. Phlizon is a better value, in our opinion. They also supplement the white light from the COBs with red, blue, IR and UV diodes.

Rapid LED only give you the white light from the CREE CXB3590 COB LEDs. You have your choice of 3000K, 3500K or 5000K. We recommend 3000K for flowering and 5000K for vegging. If you are using the light for all stages, 3500K is ideal.

The Rapid fixtures are modular, meaning you can easily expand them by adding more COB lights. This particular fixture features four of the COBs. Each one uses 75 watts, for a total of 300 watts. Eah COB is basically like its own UFO LED grow light.

Since they are arranged in a single row in this fixture, they give you a rectangular coverage area of 2 by 4 feet. As mentioned above, the powerful COBS, aided by the reflectors, emit an incredibly intense light that penetrates deeply into the canopy.

However, the light is much more focused than the quantum board or bar style lights. This means you get that incredible intensity toward the center of the coverage area, but much less output around the edges.

This can be a positive or a negative, depending on your needs. For most people, a more even coverage area is better, meaning the above fixtures are better than COBs. But if you want COB lights, Rapid LED gives you the best.

Of course, they are also expensive, which is why we generally recommend the Phlizon fixtures over these. That said, you can lower your costs somewhat with these Rapid lights.

Rapid LED gives you the choice of buying a fully assembled fixture, or buying one of their DIY kits. With the kits, you have to put together the fixture yourself, but this is quite easy to do. In return, you save some money.

 

Best High Bay LED: Mars Hydro SP3000 LED Grow Light

Finally, we have another light from Mars Hydro. As you can see from the form factor of the Mars Hydro SP3000, it is designed for a high bay application. This means it is ideal for use in a warehouse or greenhouse, where you hang rows of these lights high above the plants.

However, they work well in a 2 by 4 tent, too. That is the core coverage of this light. The spectrum is a bit different from the previous Mars fixture above, in that this one does not have any infrared diodes.

The other big difference is that the SP series uses top-of-the-line components, while the TS series does not, in order to cut costs. Specifically, this light has the Samsung LM301B chips and a MeanWell driver. The driver is dimmable, and you can dim multiple daisy chained lights together.

With the higher quality components, this light achieves an output of 1136 umol/s at 18 inches from the canopy, while only consuming 300 watts. That gives you an efficiency of 2.78 umol per joule. Mars claims a yield of up to 2.5 grams per watt.

This light has a large heat sink attached to the back of it, which works to dissipate heat more effectively. It ships with hanging equipment and is guaranteed for 3 years after purchase.

 

Best 300 Watt LED Grow Light: Final Thoughts

As mentioned in the introduction, we wanted this list of the best 300 watt LED grow lights to be different. That means no lights that are labeled as ‘300 watts’, but that don’t use even close to that (and that don’t even exist anymore, in many cases).

All of the lights we recommended above use around 300 actual watts. They are also currently the best LED grow lights available in that power category.

I’m not sure why the other lists all have so many lights on them that have not been available for years now. I suppose they just haven’t gotten around to updating their lists in the past 5 years.

Either way, the lights above are all available and all great. Our top recommendation is the Spider Farmer, because it offers the best value overall. It is also a bar style light, which is now the most popular style in the industry, due to its ideal spectrum and even light distribution.

The quantum board lights (the 2 by HLG and the one by Mars Hydro) also give you those same advantages. They were the lights that were most popular before the bar lights took over and are still great options. Honestly, it’s really just a matter of preference.

Finally, we also have a COB fixture. COBs have the advantage that they give you a deeper canopy penetration. But they do so in lieu of a more even light spread. COBs are better when you have a single plant, or single row of plants. That’s when deeper penetration is useful.

If you have a more even canopy, then the more even light spread of the bar or quantum style lights is better. And finally, the high-bay light is ideal if you are growing in a single level greenhouse or warehouse.