Mars Hydro 300w Review: Grow Plants Indoors


When you’re attempting to grow plants indoors you need the right setup. If you don’t have everything perfect, your plants will either not grow or wilt quickly.

One of the things you need is a grow light, which is what the Mars Hydro 300w is.

It’s an indoor LED grow light created by the company Mars Hydro. The company is in China which can be troublesome.

Sometimes with Chinese or Japanese companies the quality isn’t as great as they claim it to be. Then you really can’t contact them because of a language barrier.

But Mars Hydro created a site in California that can help with customer’s needs. It’s impressive that they recognized this customer service issue and found a solution.

The Mars Hydro 330w is a full spectrum indoor grow light. It gives off a purple tint that plants and veggies absorb from seedling to harvest. It has 50,000 to 100,000 hour lifespan.

It only takes up to 132w of electricity and can replace a 150w HID light. It’s good for a 2 foot by 2 foot space.

It’s easy to assemble. You can plug in to turn it on or unplug it to turn off. They also include an autotimer if you would rather do that.

It has 60 small LED lights and each light produces 300w while consuming only 132w.

It should hang above you plants from anywhere between 12 inches through 30 depending on your plants’ need.

It has a built in silent cooling system to keep the lights cool, that way it won’t burn your plants.

It’s safe and eco-friendly. All Mars Hydro LED grow lights have been tested and passed US authoritative ETL certification. The lights are built with isolated material. There aren’t any chemical or electronic smells while it’s working either.

They offer a 12 month warranty and 30 day money back guarantee if something is wrong with the light.

What’s most interesting is that you won’t find this light on their site. This model is actually one their older models. They only sell it on Amazon and Ebay. Instead, they hope their customers will try their newer models.

But growers like this model, it’s very popular in forums and discussion boards.

How Do LED Lights Work?

Now you might be wondering how an LED light helps plants grow. After all, they need sunlight, not artificial light.

LED lights that have full spectrum bulbs actually come pretty close to mimicking natural sunlight, which is ideal for seedlings. The full spectrum allows both warm and cool light—this means red and blue types of light—that mimic the natural solar spectrum.

You should use LED lights when growing things indoors because seedlings need a lot of light. In fact, lighting is one of the most important tools to make sure you actually grow healthy crops or flowers.

If you don’t have a bright enough light, your seedlings will be weak and leggy. The term eggy means that there is too much greenery and not enough roots to support it. It makes the plant a bit floppy.

LED lights are good for lighting because they don’t give off a lot of heat while still giving intense light. They also use half the electricity so you can save money on bills.

LED grow lights also let you control how long your plants are under the lights. Depending on the plant, they will want a specific amount of light and shade.

These lights also let you try your hand at growing plants that aren’t from your area. Being able to control the lights means that you can copy the plant’s natural habitat even if you don’t live in it.

What Insiders Think About the Mars Hydro 300w

MarsHydro LED Grow Light

Growers like that it’s one the cheapest but well made grow lights out there. Though people have pointed out that this light isn’t great for flowering and blossoming. But it’s good for seeds and veggies.

Many people are applauding all the safety precautions this company has taken. From being certified, to having large fans, and a heatproof tube to prevent a fire.

They also appreciate that the company doesn’t run their LED diodes to their max capacity. By doing this, they ensure that they last longer and are less likely to burn out.

As mentioned before, reviewers are quick to point that customer service can be a problem in China. But applauded that Mars Hydro opened a center here in the US.

What People from Amazon Thinks About It

Grow Light

On Amazon, It has a 4.5 star rating and over 900 reviews. Beginner growers really love this light. The price is great for them because they aren’t sure what they need.

It was easy for them to set up and it’s helping their plants. Many people have bought more lights from this company because of the good experience.

There were complaints about the fact there was no on/off switch. Some people have said theirs have stopped working after 6 months, but these seem to be outliers. Some people’s plants didn’t blossom, but it’s already been established that this light isn’t the best for that.


  • Perfect for beginners
  • Cheap
  • Well made
  • 50,000 to 100,000 hour lifespan
  • Safe
  • Passed US authoritative ETL certification
  • Easy to assemble
  • Produces 300w while only using 132w
  • No chemical or electrical smell
  • 12 month warranty and 30 day return


  • Not for professionals
  • Customer service is iffy but getting better
  • Small
  • Not good for flowering or blossoming
  • Cooling fan can get a little loud
  • LED lights can burn out
  • No on/off switch

Other Products from Mars Hydro

If you like this light and want to purchase more from this company, like many other growers. We’ll give you a run down on their products.

If you liked your first light, you may want to upgrade to this bad boy. It replaces a 250 watt HID light. It still offers the same full spectrum of the 300w.

It only uses 265w and gives out 600w. This is bigger, having a growth size of 4 by 4 feet.

It still doesn’t have an on/off switch, but it does have an autotimer. It is also ETL certified and the plug uses VDE and UL certified wires. It also has the same cooling fan to prevent overheating. 

You should still hang it 12 to 30 inches above your plant, depending on its needs.

It has a 4.5 star review. People like it for the results it produces, the price, and how well it’s built. One reviewer actually bought 10 of them because they liked it so much.

Some people complained that the fan was loud. There were also a few issues with the customer service.

Led Grow Light Bulb 24W Grow Lights Lamp for Indoor Plants Grow Light Kit with Hanging Cord and Hooks for Basement Hydroponic Garden and Greenhouse
  • [LED Grow Light Kit] - You will get all things for your indoor plants. 24W LED plant light with 12...
  • [Great Heat Dissipation] - The indoor plant light housing is made of high quality aluminum to...
  • [24W Plant Grow Lamp & 12 Super Bright LED] - The led growing light bulb is brighter more efficient...
  • [Easy to Set UP and Use] - Standard E27, 12 feet hanging cord with on/off switch, easy to hang...
  • [Seller Warrant] - Buy with confidence, we always stand behind our growing lamps, we could offer...

This is a 24w growing light. This good if you have only one plant that you want to grow. It can also work as a supplementary light for the rest of your setup. It has a 50,000 hour lifespan.

It can fit any standard E26 socket. There is no special lamp needed, a desk lamp can work.

It has a 4.2 star rating on Amazon. People like it because it gives off little heat, it’s easy to use, and the results are amazing. Many people were surprised at how much it helped their plants grow with so little light.

It seems there were a few times that when people order two of these lights, only one worked. Though they were sent replacements pretty quickly.

If you’re going to spend a lot of time in your garden while the lights are on, these are a good investment. Even if you don’t look directly at the lights, it can get bright and strain your eyes.

They work under a variety of different lights. The green color is supposed to correct the colors so it will look like natural sunlight. This will help you see better. It can be hard to see in the purple light.

It blocks all UVA and UVB rays and protects your eyes from infrared wavelengths, glare, and reflection.

These glasses have a 3.9 star rating. People back up the claim that you can see easier while wearing them. They also appreciate the price. They even can fit over prescription glasses.

Some felt that the plastic seemed cheap but that’s really the only complaint.

These are heavy duty ropes that you can use to adjust the height of your grow light. They are 8 inches long and can handle up to 150 pounds.

There are 4 carabiner clips that are easy to undo and automatically lock. Their loose proof design ensures safety.

It has a 4.6 star rating. People like this much more than chains. They find it much easier to adjust their lights when using it. Plus, you can’t go wrong for the price.

Many people suggest to tie a different knot before hanging anything. They feel the knot it comes with isn’t secure enough.

MARS HYDRO Grow Tent 2.3'x2.3' 1680D Canvas Reflective Mylar Grow Tents with Removable Floor Tray for Indoor Hydroponic Plant Growing Room 27"x27"x63" for TS600/SP150
  • 【LOCK ALL LIGHT INSIDE】MARS HYDRO Indoor Grow Tent interior is made of diamond mylar which is...
  • 【DURABILITY GROW TENT】Stable metal corner adapters and poles are the trustful supporters of the...
  • 【EASY OBSERVATION FOR YOUR PLANTS】Special observation windows are made by double layers of...
  • 【REMOVABLE TRAY KEEP FLOOR CLEAN】The package includes a removable waterproof floor tray to hold...
  • 【GUARANTEED BY MARS HYDRO】MARS HYDRO grow tents are easy to install even if you've never done...

In case you don’t know what a grow tent is, it’s a small tent where you can put a specific plant in to grow. You get to completely control its environment. This is good for finicky or sick plants.

They come in a variety of sizes, so you can easily find one that will fit in your home.

These tents don’t let light leak out due its double stitching and 1680D canvas. The inside is made of 100% reflective Mylar lining, so no light goes to waste.

They have metal corner adapters if you want even more steady support. The reinforced tent poles make sure that it won’t collapse on your plant. Even the zipper has extra protection to keep it from sliding down.

There’s a ventilation system on the roof, side, and the lower parts of the tent so the plant gets plenty of air.

It features a removable floor tray for easy cleanup and you get a tool bag to store your tools.

It has 4 star rating. People found it easy to set up and were happy that it didn’t need special tools. They think they got good quality for the price.

Some people felt that it needed lower vent holes. Others felt the material was a bit cheap.

What We Think About Mars Hydro 300w

Grow Light on plant

If you’re looking for a professional grow light, then you should look elsewhere. This is the perfect light for beginner growers or people who do this as a hobby.

A professional grow light will cost 3 times more than the Mars Hydro 300w.

There were a lot of negative reviews about the quality but it seems like Mars Hydro has sorted it out. There are a lot more positives than negatives now.

If you’re new to indoor growing and unsure what to get, this is the perfect starter. It’s small, easy to use, and is great for seeds and veggies. It can help with blossoming occasionally, but if that’s what you’re looking for, you should look elsewhere.

It seems like this company’s customer service has gotten better but still has room to improve. It’s great that they opened a center in the US, but people are still having a hard time communicating.

Overall, we think this is a great light for starting out. It’s not a lot of money lost if you decide indoor growing isn’t for you. It’s not complicated to use and does help with growing.

Last update on 2021-09-20 at 08:43 / Affiliate links / Images from Amazon Product Advertising API

Glory Lennon

Glory writes about flower gardening and other gardening subjects in addition to her serial romance novels from the Pocono Mountains of Pennsylvania, USDA Gardening Zone 5b

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