Mars Hydro 300W LED Grow Light Review (2020)

Mars Hydro 300W LED Grow Light Review

Sunlight is the most important and crucial element that is needed when you grow a marijuana plant out in the open. It is the natural light that helps the plants grow. When growing indoors, this natural light is recreated with the help of grow lights. Over the course of this article, we shall be taking a closer and detailed look at one of the best grow lights that you can find in the markets, especially if you are looking forward to buying a 300W light. This is the Mars Hydro 300W LED grow light.

In 2020, there are hundreds of brands which are willing to sell you their grow lights on Amazon. It is so easy to buy a light – in just a few clicks you can have it delivered to you in 24 hours! In such a time and age where there are so many sellers, how do you decide which is the best LED grow light for your marijuana plants? We are here to help you simplify that decision making process. The Mars Hydro 300W LED grow light is one of the best such names in the segment and our grow light review is going to make it quite clear for you!

In this article, we shall be talking in brief about why grow lights are important when you are growing weed indoors – and specifically about LED grow lights. We shall then be taking a quick look at how Mars Hydro the brand is, followed by the Mars Hydro 300W LED Grow Light review where we shall be talking about every aspect of this grow light in great length. All the way from its design to its lighting and power details and even the cost and warranty aspects of it! We shall be looking at the pros and cons of buying this light in detail towards the end, followed by a final review and then answers to some commonly asked questions. Let us begin:

What is the Importance of Grow Lights for Growing Marijuana?

The natural sunlight helps plants with two major things – first off, it helps aide the development of chlorophyll, which is an important pigment for the proper growth of any plant. Secondly, it is important because plants use sunlight as a stimulus to prepare their ‘food’. It is the main source of energy for the plants and the more intense the sunlight the better they grow. The marijuana plant in particular requires sunlight as much as 22 hours during its younger phase and as it matures it needs about 10-12 hours during the flowering phase. These ideal conditions might not be met outdoors, but when growing indoors, a customized lighting setup can be provided. 

This customized lighting setup allows you to adjust the brightness, the amount of time you want to provide the light, as well as the distance from which you want to provide the light. You can also refine the intensity of the lighting if you are using a grow light that supports dimmers. You can also program them to turn on and off on a specific time using timers. These are all important elements of a grow light which help ensure the plants are getting the best possible scenario for their growth. This is not possible under natural light but grow lights make it possible. 

What are LED Grow Lights?

While there are a lot of options that growers have when it comes to buying grow lights, LED grow lights happen to be the best of the lot. Other than LED lighting, there are the options to get a High Intensity Discharge (HID) grow light, such as a Metal Halide or a High Pressure Sodium (HPS) grow light. In addition to that, there are other types of lighting such as Fluorescent lights, but the problem with them is that they require an extensive setup including ballasts, etc. and aren’t as effective when it comes to spectral length.

LED grow lights such as the Mars Hydro 300W LED grow light resolve all these problems. They are simple and easy to use, offer a full-spectrum making them very similar to the natural light of the sun, as well as consume very little power. LED grow lights consume almost half the power as that of HID lights and can last almost twice as long. Most LED grow lights can last easily for 50,000 hours while some even promise you of 100,000 hours or more. Most of these lights offer a longer warranty period as well – ranging up to 3 to 5 years in some cases. These lights are also simpler to set up, easier to maintain and easier to dispose of as well, as they do not carry any toxic chemicals inside them! 

How is Mars Hydro as a Brand?

When you look at brand Mars Hydro, you have to know that they have been around for quite some time now. For 9 years, the company has been relentlessly providing growers with some of the best lighting solution for growing indoor plants. Marijuana growers have trusted this brand and it has show quite a good result. You get really good quality lighting and it has been approved by various safety standards as well – ETL in the US and Canada markets and CE and Rohs approvals for the European Union have been acquired. 

All of Mars Hydro’s lights, including the Mars Hydro 300W LED grow light, have a minimal 3-year warranty period and the company has repair centers based in the US, Canada, Australia, the United Kingdom as well as Germany. The company is also quite easy to contact and you can call them on their service helpline as well as mail them for any problems. All in all, Mars Hydro is a credible and reputed brand when it comes to buying grow lights online.

Mars Hydro 300W LED Grow Light Review: The Best Grow Light in 300W Segment?

MarsHydro LED Grow Light 300W 600W 1200W Full Spectrum for Hydroponic Indoor Plants Growing Veg and Flower
  • HIGHER YIELD: Updated MARS ECO 300W light made with newest SMD leds which can get 30% higher PAR than old led. Full spectrum light perfect for all plants at all...
  • ENERGY-SAVING: Consuming only 120watt±10% with the same effect of typical 150W hps or HID grow lights. Enough for 2' X 2' growing area. Using 4 Mars 300 watt...

We have broken down our review of this grow light into various sections and segments where we are going to review each of them in detail. We shall be giving a rating to all these aspects and based on that we shall assign a final rating to the grow light. After our review, we also look at some of the pros and cons of this grow light. 

1. Design and Durability – 4/5

When it comes to design and durability, the Mars Hydro 300W LED grow light scores pretty well. Although it has a very generic look and feel and doesn’t stand out when kept along with most other grow lights, it ranks pretty high in terms of durability! When you look at the grow light, the first thing that strikes you is that this is one single panel and is not divided into multiple panels like several other grow lights. It has cooling holes on all four sides, and comes along with a bass cooling fan inside it. The grow light features daisy chaining as well – which is a welcome addition (we shall talk in detail about it in the ‘power’ section of our review).

The grow light comes with a reflective frame design, which is a great way to make sure that the intensity and uniformity of the light that comes out of it can be improved. It also helps make sure that chlorophyll is generated by the plants in a better manner. The light is quite durable and survives bumps and scratches. It also comes with all the approvals and safety ratings that make sure it can function well without being a safety hazard. Lastly, it is also very easy to set up and install and even growers who are absolute ‘beginners’ can set it up with ease. 

2. Spectrum and Lighting Details – 4/5

When it comes to the spectrum and lighting details, this grow light scores quite decently. To begin with, it is a full-spectrum LED grow light which functions on 400-410nm, 440-450nm, 450-460nm, 630-635nm, 650-660nm, 730-740nm and 2700K-3000K. The light that you get from this grow light is very bright and can even damage your eyes if you look directly at it so avoid doing that! 

However, one thing that is missing from this grow light is that there is just one ON/OFF switch and you cannot switch between the vegetative and bloom modes. You have to use the same kind of lighting throughout the plant’s life cycle. While that’s not something that is bad for your plants, but it would have been even better had that feature been provided. The SMD LEDs which have been used in this grow light are much better compared to traditional LEDs and offer about 30% higher PAR scores which make it an impressive performer. However, we’ve cut one point from the rating due to the absence of the VEG/BLOOM switch.

3. Brand Value and Credibility – 4/5

Brand value and credibility is another department where this grow light scores pretty well. We have already taken a detailed look at the Mars Hydro brand above. To refresh your memory, it has been around for close to a decade now and has been working really well on getting all the safety standards right. The company has warehouses all over the world and also houses repair centers in the US, UK, Canada, Germany and Australia. It is easy to reach out to and is quite active over phone and email support. All in all a very good and credible brand which millions of growers from all over the world know about and trust so you can’t really go wrong about that!

4. Coverage Offered – 3/5

Now this is one area where the grow light stumbles a little. The coverage is frankly a little too small – but good for you if you are a very small scale grower growing only a couple of plants for your personal consumption. Other that that you’ll need to buy multiple such grow lights if you want to cover a larger area. It offers a core coverage of 2ft x 2ft, which is useful during the flowering phase while the maximum coverage you can get is that of 3.5ft x 3.5ft which can be considered during the vegetative phase. However, while the coverage might be limited the lighting that comes from this grow light is pretty impressive and quite intense. Bright lights are great for your plants but not so great for your eyes so take care to not directly look at it. The grow light is good enough for growing on a small scale for indoor growers who want to grow in grow tents using traditional soil-based methods and it is also of use for growers who want to grow hydroponic weed. However, the coverage could’ve been better. 

5. Power Performance and PAR Value – 3.5/5

The power performance is really impressive but the PAR value is okayish at best. We found out during our Mars Hydro 300W LED grow light review that the grow light consumes only about 120W of power at all times – which is pretty good when you compare it with the 300W equivalent output that you are getting! The power consumption is less than half of the output making it a great choice for growers who don’t want a high electricity bill! One good thing about this grow light is that it supports daisy chaining – which means you can plug another grow light on to this one and you don’t need to plug multiple grow lights to multiple power outlets as you can chain one to the other. Such a ‘chian’ of up to three grow lights is ideal. The lighting is also quite intense and helps ensure that your marijuana plants grow faster. 

6. Cooling – 4/5

Cooling is another department where this grow light performs really well. While doing the Mars Hydro 300W LED grow light review, we found out that it doesn’t really overheat. First off to begin with it is not a really big device – in addition to that, the holes on the sides ensure that all the heat flows out – and the fan doubles down on that. While it cools the light really well, another great thing about this fan is that it operates rather silently and generates a maximum sound of about 49 dB which is pretty low for a grow light! 

7. Cost, Warranty and Delivery – 4/5

Given that the coverage is pretty low, the price is quite justified. Apart from that, the grow light offers a three-year warranty that you get on all Mars Hydro products. Amazon delivers this grow light on time. We found that the Mars Hydro 300W LED Grow Light is often not in stock because it is in such huge demand that people tend to buy it as soon as it comes in stock. So make sure you’re setting your alerts and reminders so that you can buy this grow light when it comes back in stock. 

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Pros and Cons of Mars Hydro 300W LED Grow Light

Here is a look at some of the pros and cons of this LED grow light:


  • Cost-effectiveness is one of its biggest pros. The product is quite cheap.
  • It is a good grow light for beginners as it is easy to use and install
  • Doesn’t heat up much and the fan isn’t loud
  • Very bright – helps the plants grow taller and helps boost flowering
  • A great choice for small-scale growers
  • Supports daisy-chaining
  • Full-spectrum lighting


  • Doesn’t have a separate VEG and BLOOM switch
  • The core coverage area is smaller than what most people would expect it to be
  • PAR values could be improved

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Final Rating and Review for Mars Hydro 300W LED Grow Light

We give this grow light four out of five stars. It is a great choice for beginners who want to start off small. It is also a good option for buyers who want to grow weed but in a lesser quantity. This is an ideal LED grow light for small-scale marijuana growers. Those who have been around the scene for some time might want to buy this grow light as a backup light in case one of their main light goes bad and has to be repaired. This is a decent product but there are many a better options available out there. 

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Frequently Asked Questions (FAQs) About Mars Hydro 300W LED Grow Light

Here are the answers to some of the most common and frequently asked questions about this grow light from Mars Hydro

1. What other types of grow lights does Mars Hydro make?

Mars Hydro makes several other types of grow lights. In addition to grow lights, the company also makes grow tents and LED lights for aquariums. These lights vary in size, coverage, the kind of lighting, number of LEDs, etc. While they offer a very large range of items, we recommend that you should check out their store on Amazon or their website for more details on the products that they offer. 

2. Is this grow light safe to use?

Yes, this grow light is quite safe to use and has been certified so by several ratings agencies in the US and EU regions.

3. What is the warranty that the Mars Hydro 300W LED Grow Light offers?

The standard 3-year warranty period that Mars Hydro offers on all their products is applicable to this grow light as well. In addition to that, there’s also a limited return period that Amazon offers (which varies from region to region so do check it out on the product page). 

4. Is this a trusted company?

Yes, Mars Hydro has been around for close to a decade now and has manufactured millions of LED grow lights, grow tents as well as other similar equipment that growers need. The company also manufactures aquarium lights. 

5. Is it legal to use this grow light? 

Yes, it is legal to use this grow light but if you want to make use of Mars Hydro 300W LED grow light for growing marijuana, you might want to check what your local laws are regarding that. Not all regions allow growing of weed – and even those which do might limit the number of plants that you are growing.



We hope that this article on Mars Hydro 300W LED grow light review helped you know more about the light than you did before heading into it. We hope that you can now make a better and well-informed purchase decision! All said and done it is a great product for those looking forward to buying a grow light for growing personal-scale marijuana, or for those who are looking forward to buying some backup lighting equipment! Do let us know over the mail or in the comments below if you still have any questions regarding this product. Till then…

..Happy Growing!


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