MarsHydro Mars300 (300w) LED Grow Light Review

Growing plants indoors requires delivering the proper spectrum of light, with the perfect amount of intensity to make photosynthesis function properly. LEDs offer several advantages over standard HID or fluorescent lighting options. One reason being that they’re able to deliver a fine-tuned spectrum in specific wavelengths.

Mars Hydro 300w LED Review

Science has taught us which are needed by plants, so more-effective grow lights can be built to cater to their exact needs. Ideally, you’d have an overall balanced spectrum with a heavier emphasis in the red, but with an arrangement that incorporates a bit of each end of the chart. However, LEDs are known to require an upfront budget as they’re typically much more expensive than other lighting setups.

MarsHydro Mars300

If you’re one who’s stretching your budget and wanting to find an affordable yet effective lamp for your garden, the MarsHydro Mars300 LED Grow Light is a fine choice. Priced just under $100, it’s an excellent entry-level LED that’s best used for seedlings, clones, leafy greens, sprouts, or vegging. We’re not going to lie and say it’s an amazing lamp for blooming or flowering – it’s not really ideal for that. There are many better options if you want a professional panel, but you’re going to have to spend double, triple, or even quadruple the price (or more!).

MarsHydro Mars300


With an assortment of 60 individual, 5 watt Epistar diodes, the MarsHydro Mars300 offers a well-balanced spectrum that incorporates a broad range of wavelengths: 430~440nm, 450~475nm 620~630nm, 650~660nm, and white. This spectrum is suitable for all stages of growth which is why many growers have said that LEDs provide faster, healthier growth since they know exactly which kind of light to deliver. With around 140 watts of power consumption, the diodes aren’t driven to their maximum capacity. In order to provide longer lasting parts, MarsHydro made a smart choice by not running all of the LEDs over a stable limit.

MarsHydro Mars300

Each diode is behind a small lens that projects the light in a mixed 90 and 120 degree pattern to provide better coverage to the garden canopy. Ideal for growing within a 24 inch x 24 inch growing area, it has a small footprint – but that’s to be expected. The fixture itself measures just 12″ long, 8″ wide, and 3″ thick.

MarsHydro Mars300 par chart

Ideal Uses

Although it technically CAN flower just fine, you may be unimpressed if you’re going from HPS to LED with a small panel like this. It obviously won’t perform near as well as a 400 watt HPS, but likely perform the same or near what a 250 watt HPS could produce under ideal conditions. Of course there are so many variables that go into hand when growing – but the power of your lighting is a crucial one. We’ve seen the MarsHydro produce some flowers, but they were definitely a bit lackluster compared to what one of the current top rated grow lights can produce.

The MarsHydro Mars300 does fantastically well with seedlings, cloning, and vegging. The balanced full-spectrum is what the plants are craving and it can deliver it with the right amount of intensity. It’s not super-powerful so it’s perfect for smaller plants or small-scale grows like PC case grows, stealth boxes, or closet growing.

MarsHydro Mars300


Inside there’s a large diameter cooling fan that’s constantly spinning when the light is turned on. It blows cool air over the heatsink that dissipates the hot temperatures away from the diodes to create a better environment for them to run at their best efficiency. If the LEDs become too hot they run the risk of burning out or failing over time. This is the main reason you see pretty much all LED grow lights with large cooling vents, fans, and heatsinks – they do a wonderful job.

Protecting Diodes

If you look closely at the arrangement of the diodes, you’ll see a small protector situated right next to each LED. These are designed so that if one diode burns out, it won’t cause a successive reaction and shut off all of the diodes. Although you shouldn’t expect any of them to burn out, it protects against a catostraphic failure so the entire panel doesn’t turn off if one stops working.

MarsHydro Mars300


In order to assure better quality and overall safety, MarsHydro took a few precautionary measurements when they put together the 300 panel. Each one of the plugs have passed UL certification standards to guarantee that they’ve been designed and manufactured correctly.

MarsHydro Mars300

Great Service

Although the MarsHydro Mars300 is made in China, they offer some really good customer service. Chinese panels have been known to be of lesser quality – that’s why MarsHydro opened up two United States based service centers. The lights seem to be made very well, but if you ever have an issue with it, you won’t need to go through a complicated waiting game to ship it all of the way back to China. With email contact, you can arrange a replacement should any problems arise. We’ve owned our MarsHydro panel for over a year and it’s still alive and kicking with no lesser brightness or efficiency than it was when we originally bought it.

Final Thoughts

With an average lifespan of 50,000+ hours, the MarsHydro Mars300 LED Grow Light is an excellent choice for those that don’t want to exceed spending over $100 on a lamp. Although it has a full spectrum that’s properly balanced, it’s not the ideal choice for those who want to use it solely for flowering. However, it will produce decent flowers, just not the best! As far as using it for seedlings, cloning, and vegging – it’s a great choice! We found that young plants absolutely love it and did significantly better underneath the MarsHydro than any fluorescent fixture we’ve used in the past. Overall, we give the panel a solid 8 out of 10.

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