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What size light do I need for my cannabis grow tent?

What size light do I need for my cannabis grow tent?

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Cannabis may be nicknamed weed, but if you’ve ever attempted to grow, you know it needs careful tending to grow into a healthy, cannabinoid rich flower. From the soil composition to the air temperature and humidity, a good grower knows that nothing can be left to chance – least of all the lighting. 

Why good quality lighting is important in a grow tent

Growing cannabis plants inside gives you the maximum amount of control over every element of your grow. But since you’re inside, getting the right lights is of the utmost importance because cannabis is a light sensitive plant. 1

Cannabis is a photoperiod-dependent plant, which means its growing stages and yield are directly influenced by the amount of light it receives. Without the right amount of light, your plants will stagnate and fail to move into maturity. 

Not only will high-quality lights help each stage of your grow move more smoothly, they can actually increase the yield of your plants. The type of light and intensity of light can also affect your cannabinoid density, and the terpene profile. 2 3

But it takes more than just a good set of growing lights to have a successful harvest. You also need the right amount of lights and the proper intensity for your tent. If your setup is too big for the lights, each plant won’t get the energy it needs to grow strong and flower. If your lights are too powerful for your setup, they can damage your plants before they have a chance to get started, or as they flip to flower grow too close to the light. 

Factors of a good growing light

What makes a high-quality light? You’ll need to use several factors to find the best light for your grow set up, including: 

  • Efficiency. An energy efficient light uses less electricity to run, which costs less.
  • Energy consumption. Part of determining a light’s efficiency is the energy consumption it takes to run. An efficient light will consume less energy than a traditional one, and  LED lights are more energy efficient than older grow lights like high-pressure sodium. 
  • Longevity. How many hours will the light last? You don’t want to invest in an expensive light, only for it to burn out after your first grow. 
  • Affordability. Every grower has a budget, and the best light for your grow tent won’t break the bank. 
  • Maximum lighting. How powerful is the light? Is it always running on maximum power, or is it dimmable for different grow stages?
  • Cooling system. In the late stages of a grow, lights need to run for 12 hours at a time, which can easily lead to overheating. Does your light have a cooling system to keep it from getting too hot and burning out? 
  • Your grow space. Are you working in a grow tent or a converted bedroom? Large spaces need more lights than smaller spaces, and adding heat may be more desired in some grow areas than others. 
  • Brand. We all want things that work like they should. Brand loyalty is important to experienced growers to keep elements consistent. 

The best size grow lights for grow tents

One of the most important factors for getting the best grow lights is making sure they fit your grow space. Some lights are too powerful for a 2×4 grow tent while others would struggle to provide enough light for a 5×5 space. Mars Hydro creates grow lights for every size space with the power, energy efficiency, and longevity you’d expect. 

But sorting through all of your options can be overwhelming, especially for a new grower. Here you’ll find the best lights for every size grow tent, picked by the experts at Mars Hydro themselves. 

Best lights for 2×4 grow tent: Mars Hydro TSL 2000 or SP 3000

Mars Hydro TSL 2000

Best for: 2×4 grow tent 
Energy consumption: 300w
Longevity: 50,000-hour lifespan

The TSL 2000 is a best seller for growers with small spaces. The rectangular LED light works best for rectangular spaces and the reflective hood ensures all of the light is dispersed evenly. The light is dimmable to adjust as needed and gives off a unique spectrum of red, white, and blue light that’s beneficial to plants’ growth stages. 

Mars Hydro SP 3000

Best for: 2×4 grow space 
Energy consumption: 300w
Longevity: 50,000-hour lifespan 

For the smartest lights in a small grow space, the SP 3000 is the way to go. This light is a single strip of dimmable LED lights made with Samsung LM301B chips for energy efficiency and low heat output. It produces a blended light spectrum to mimic natural sunlight’s penetration into the plant while a high ratio of red light encourages dense bud production

Best lights for 4×4 grow tent: Mars Hydro FC-E4800 or TSW 2000

Mars Hydro FC-E4800

Best for: 4×4 grow tents
Energy consumption: 480w 
Longevity: 50,000-hour lifespan 

With six rows of LED and over 2,600 diodes that produce a full spectrum of red, infrared, ultra-violet, and white light, the FC-E4800 has everything you need for a successful grow. The lights are adjustable and dimmable for full control at each stage of the growing cycle. It also has a passive cooling bar to keep the lights from overheating. 

Mars Hydro TSW 2000

Best for: 4×4 grow tents 
Energy consumption: 300w
Longevity: 100,000 hours 

The TSW 2000 is a best-seller that works well in rectangular grow areas. It has a reflective hood design that ensures the light is evenly dispersed across all plants and produces a unique spectrum of white, blue, red, and infrared light to help your plants grow dense flowers. It’s also dimmable for all stages of plant growth. 

Best lights for 3×5 grow tent: Mars Hydro SP 6500

Mars Hydro SP 6500

Best for: 3×5 grow tent 
Energy consumption: 650w
Longevity: 50,000 hours 

The SP 6000 is a single bar packed with over 2,300 LED lights made from Samsung diodes. It’s energy efficient with minimal heat output and enhanced red light to encourage large flowers. This light is also dimmable so you can have the perfect intensity for every stage of your grow. 

Best lights for 5×5 grow tent: Mars Hydro FC 6500, FC 8000, FC-E6500, or FC-E8000

Mars Hydro FC 6500

Best for: 5×5 grow tent 
Energy consumption: 730w±5%

The FC 6500 has eight strips of LED lights with over 2,600 Samsung diodes for maximum light penetration and efficiency without excessive energy consumption. The frame of the lights bends in the middle for flexible placement and the lights are dimmable. The FC 6500 also has enhanced blue and red light to ensure uniform plant growth and easily covers a 5×5 flowering area

Mars Hydro FC 8000

Best for: 5×5 grow tent 
Energy consumption: 800w

Designed for commercial grow spaces, the FC 8000 has eight rows of LED lights made with over 2,900 Samsung diodes for even light penetration and maximum efficiency. This powerful is dimmable, self-cooling, and has enhanced red and blue light to boost plant growth. 

Mars Hydro FC-E6500

Best for: 5×5 grow tent 
Energy consumption: 730w

Perfect for hobbyists and professional cultivators alike, the FC-E6500 has six rows of LED lights made with over 3,500 diodes for maximum intensity and energy efficiency. It produces a unique light spectrum with enhanced red and blue light for optimal flowering. All of the lights are adjustable, dimmable and self-cooling. 

Mars Hydro FC-E8000

Best for: 5×5 grow tent 
Energy consumption: 800w

With eight strips of LED lights, over 3,900 diodes, and a unique smart chip arrangement, the FC-E8000 is both powerful and energy efficient. It produces a unique spectrum of light with enhanced red light to encourage maximum flowering. The lights are adjustable and dimmable, and self-cool to keep your grow safe. 

Bottom line

The right lights in your grow tent can make or break your harvest. Rather than sorting through dozens of options, the experts at Mars Hydro make it easy to identify the best lights for the size of your growing space. With a unique spectrum of light to encourage flowering, built-in cooling systems, and 5-year product warranty, your plants will be in good hands. 


  1. Zhang M, Anderson SL, Brym ZT, Pearson BJ. Photoperiodic Flowering Response of Essential Oil, Grain, and Fiber Hemp (Cannabis sativa L.) Cultivars. Front Plant Sci. 2021;12:694153. Published 2021 Aug 2. doi:10.3389/fpls.2021.694153
  2. Hawley, D., Graham, T., Stasiak, M., & Dixon, M. (2018). Improving Cannabis Bud Quality and Yield with Subcanopy Lighting, HortScience horts, 53(11), 1593-1599. Retrieved Aug 2, 2022, from https://journals.ashs.org/hortsci/view/journals/hortsci/53/11/article-p1593.xml
  3. Magagnini G, Grassi G, Kotiranta S. The Effect of Light Spectrum on the Morphology and Cannabinoid Content of Cannabis sativa L. Med Cannabis Cannabinoids. 2018 Jun 12;1(1):19-27. doi: 10.1159/000489030. PMID: 34676318; PMCID: PMC8489345.
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