The Best Grow Lights for a 3×3 Grow Tent – Pictures, Specs, and More
What are the best grow light options for a 3x3 grow tent? Consider one of the following options: A Viparspectra P1500 (budget), A Mars Hydro TSW 2000 (performance), an Optic 4 Gen 5 (Fancy), or a 250 watt HPS grow light (HPS option).
The most important factors to consider when choosing a grow light for a 3x3 foot grow space are the light intensity and uniform coverage area of the lights.
If you pick the wrong grow light your plants won’t grow to their full potential. All the options I mention below meet or exceed those requirements.
When you’re done reading this, don’t forget to check out my article on choosing the right size fan for your grow tent.
Budget Choice: Viparspectra P1500
The Viparspectra P1500 is the most modern design LED grow light from Viparspectra, a grow light manufacturer that has been around long enough to sell several generations of best selling LED Grow lights.
I bought the smaller P1000 model and wrote about it here.
This P1500 model will veg and flower your 3x3 foot grow tent. Is it the best performing or most powerful? No, but at ~$160 it offers a solid bang for your buck if you’re on a tight budget.
Why Choose Viparspectra P1500 for your 3x3 Grow Space:
I speak with growers who swear by their Viparspectra grow lights. As a matter of fact, they won’t switch to another brand despite there being options that offer higher performance (but are more costly).
These Viparspectra owners also swear by the reliability. The enthusiasm around Viparspectra is a great thing to see for a brand.
The dimming knob is very convenient. The fact that this Viparspectra P1500 isn’t overly powerful allows you to hang it close to your plants, saving you overhead space.
The light intensity is strong enough to cover a 3x3 foot grow space, preferably a grow tent for increased light reflection.
|Watts Consumed:||150 watts|
|Peak Intensity:||1000 micromoles (enough for seed to flower)|
|Coverage Area:||Flowers 3x3ft|
|Spectrum:||640-660nm (far red), 3000-3500K (white), 6500-7500K (white)|
|Where To Buy:||Click Here|
Video of my Viparspectra Grow Light:
Performance: Mars Hydro TSW-2000
The Mars Hydro TSW-2000 is a modern quantum board style LED grow light. This grow light is rated for 3x3 feet of flowering coverage, slightly larger for vegetative growth.
I bought a different size Mars Hydro model for my 2x4 grow tent at home and it looks and performs great. This is one of the best selling LED grow light brands around.
Why Choose Mars Hydro TSW-2000 for a 3x3 foot Grow Space:
This TSW-2000 is a bit more powerful than the Viparspectra P1500 listed above. For that added performance, plus a few other features, you’ll pay a bit more.
With that said, if you have the money it’s totally worth it. The stronger light will result in better yields in your 3x3 foot grow space. You can remove the drivers on the TSW-2000 and hang them outside the grow tent with the extra cord length. This helps you keep your growing temperature down.
The spectrum coming from the TSW-2000 is similar to the Viparspectra (white + red) except the Mars Hydro also contains infrared, which helps plants resist any potential disease, and grow more dense buds.
|Mars Hydro TSW-2000:|
|Watts Consumed:||310 watts|
|Peak Intensity:||1150 micromoles|
|Coverage Area:||Flowers 3x3 feet|
|Spectrum:||3000K (white), 5000K (white), 660nm (red) 760nm (infrared)|
|Voltage:||120v / 240v|
|Where to Buy:||Click Here|
Take a look at the buds people have grown with Mars Hydro grow lights:
Video of My Mars Hydro Grow Light:
Fancy Choice: Optic 4 Gen 4 COB LEDs
The fancy, high performance grow light option for a 3x3 foot space comes from another reputable LED grow light manufacturer, Optic LED.
This COB LED differs from the previous two 3x3 foot grow light options. It differs because COB LEDs are stronger, so you’ll pay for that. But you’ll read below why you get what you pay for with the Optic 4 Gen 4.
Why Choose Optic 4 Gen 4 grow light for 3x3 foot space?
Although I haven’t personally owned or tested this brand, I’ve personally spoken with owners of just about every grow light brand. Optic LED is another brand that I’ve heard growers swearing up and down by.
There are three reasons why you get what you pay for when you pay a higher price to hang the Optic 4 Gen 4 grow light in your 3x3 foot grow space.
The first reason is the larger vegetative growth coverage area. The Optic 4 Gen 4 flowers 3x3 feet, but with the high strength COB lenses, you’ll actually be able to grow plants in a 5x5 foot space until they’re ready to flower. Then you’ll have to shrink to a 3x3 foot space.
The second reason is the Ultraviolet and Infrared spectrum. I’ve noticed that Ultraviolet spectrum being included on grow lights is pretty much going extinct.
The reason is unknown because ultraviolet rays are documented to increase THC levels. My guess is grow light manufacturers want to save money (what else is new?).
Infrared spectrum is also documented to help plants grow thicker stems and more dense buds, and it’s included on the Optic 4 Gen 4.
The third reason is the very strong light, as you’ll see in the image below. Advanced growers, or growers who plan to use CO2, should take advantage of a high performance grow light like the Optic 4 Gen 4 because you need this level of intense light when using CO2. The previous grow lights I listed are not this strong.
When you put a Optic 4 Gen 4 grow light in your 3x3 tent you’ll be getting all of these benefits.
Optic 4 Gen 4 Specifications:
|Optic 4 Gen 4|
|Watts Consumed||370 watts|
|Peak Intensity:||1700+ micromoles|
|Coverage Area:||3x3 ft flower / 5x5 ft veg|
|Spectrum:||660nm (red), 460nm (blue), 3500K (white), UV, IR|
|Voltage:||120v / 240v|
|Where to Buy:||Click Here|
If you don’t mind paying extra for a top-shelf product, the Optic 4 Gen 4 is absolutely your match. Especially if you’re growing in a 3x3 foot area.
HPS Option: 250 Watt HPS Grow Light
If you have a 3x3 foot grow tent, and don’t mind using a non-LED grow light, you may want to consider a 250 watt HPS grow light. This FloraLux grow light is priced nearly the same as the budget Viparspectra option above, but will provide you stronger light.
Of course, this light uses 100 extra watts compared to the Viparspectra P1500. Should you worry about heat when you put a 250 watt HPS grow light in your 3x3 foot grow space? At 250 watts I wouldn’t worry too much. You really only have to be careful when you get to 400 watts and above.
Why Choose a HPS Grow Light for a 3x3 Foot Grow Tent?
- Flowers a 3x3 foot space.
- Offers the performance of a more expensive LED grow light at a budget price.
- Relatively low 250 watt consumption.
|FloraLux HPS Grow Light|
|Watts Consumed:||250 watts|
|Coverage Area:||3x3 feet|
|Spectrum:||Red & Blue spectrum bulbs sold separately|
|Where To Buy:||Click Here|
Which of these grow lights would I personally choose for a 3x3 foot grow tent?
Growers often ask my opinion after reading my lists. My personal choice for a 3x3 foot grow tent would be either the Mars Hydro TSW-2000 or the Optic 4 Gen 4.
Both are very good lights and I think you’ll be very satisfied with either one. The Viparspectra could be a little stronger, and I’d personally rather have an LED grow light than an HPS grow light.
I don’t recommend the 250w HPS, but occasionally I talk to people who are on a tight budget. If that’s your case you can go with one of those.
The smallest number of watts needed to grow cannabis in a 3x3 foot grow tent is 40 watts per plant, although the best grow lights use at least 200 watts for the whole tent.
Two cannabis plants will fit in a 3x3 grow tent. It can vary depending how large the plants are allowed to grow.
An inline fan rated for 150 to 175 cfm will be sufficient for a 3x3 grow tent.
If your grow tent is too hot, try cooling the room where the tent is located by opening a window or using an air conditioner. If the grow tent is too cold you may need to buy a space heater for the room the tent is located in.
You can control humidity in your grow tent by using a humidifier or dehumidifier.
- Chandra, Suman, Hemant Lata, Ikhlas Khan, and Mahmoud Elsohly. “Photosynthetic response of Cannabis sativa L. to variations in photosynthetic photon flux densities, temperature and CO2 conditions.” Physiology and Molecular Biology of Plants 14.4 (2009): 299-306.
3. Eichhorn Bilodeau, Samuel et al. “An Update On Plant Photobiology And Implications For Cannabis Production”. Frontiers In Plant Science, vol 10, 2019. Frontiers Media SA, doi:10.3389/fpls.2019.00296. Accessed 14 Oct 2019.
4. MARUO, Toru, et al. “Effects of Supplemental Lighting with Light-Emitting Diodes (LEDs) on Tomato Yield and Quality of Single-Truss Tomato Plants Grown at High Planting Density.” Environmental Control in Biology, Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists, 11 June 2012, https://www.jstage.jst.go.jp/article/ecb/50/1/50_63/_article.
5. Lin, K., Huang, M., Huang, W., Hsu, M., Yang, Z. and Yang, C. (2013). The effects of red, blue, and white light-emitting diodes on the growth, development, and edible quality of hydroponically grown lettuce (Lactuca sativa L. var. capitata). Scientia Horticulturae, 150, pp.86-91.