The best lighting for small space cannabis grows

A common issue with most home growers is space and money. Maybe you don’t have enough space to grow more that a few plants and you can’t spend a fortune on the setup.

But, of course you want to get the most yield out of every crop.

How Many Plants are You Growing?

Growing cannabis should be easy and enjoyable. Knowing and addressing your grow area will help you get off to a good start. Instead of just getting into a list of best grow lights. Lets get into some common considerations.

  • Heat: Because we are talking about growing in confine spaces, HIDs are out. They generate too much heat and will require ventilation. Depending on your square footage, under 5×5, they are impractical. LEDs and Compact florescent Lights CFLs will be your best bet, manageable with lower heat output.
  • Light Spectrum: A very important part of maximizing yield is the light spectrum. We need to be able to cover the entire growing process, from seedlings to vegetation to buds. Without too much inconvenience or added cost.
  • Square footage: The most important part of any successful grow is taking advantage of every inch of space. You can not chose the best lighting without calculating area!
  • Price: What is your budget? How much are you willing to spend on your grow room. How much for lighting alone?

Figuring out how much space per plant

I know for some this maybe too basic, but its essential! Cramming too may plants in a small area will hurt your total yields. Not utilizing the all the available space is just wasteful. So before your decide how many plants you “want” to grow. Lets determine how many you “can” grow.

Whats your Grow method?

It’s also import to take into consideration the grow method used. Some pot growing methods require more space than other.Lets look into 2 totally different grow methods that have different space requirements per plant.

  • SOG, or  the “Sea Of Green” grow method plants require minimal grow space. 12″ per plant is more than enough for a SOG grow.
  • LST or low “Stress Training” is form of growing that trains the plants by pulling them vertically. Experienced LST growers can take up over 5feet of space per plant

For the sake of simplicity, we are going to go over a basic, simple grow that uses no real grow method.

  • Seedling to early vegetation: 1 foot per plant
  • Vegetation to flowering/budding: 16″ to18″ circumference or about 1.5sq feet

This is playing it safe for a full grow. For advanced grower, the absolute minimum can be a foot per plant. This is only if you plan on having a short vegetation stage.

For example, lets say are growing in a 3’x3′ space.
3×3 = (9 square feet)/(1.5 square feet per plant) =  6 plants

How many watts you need per plant

You can calculate how much lighting you need in 2 ways, Watts and/or Lumen’s. Measuring by Watt is usually easier, but you can use our Lumen to Watt Calculator to ensure the right measurements.

  • Every 10 watts from LED produces about 600 Lumen
  • 2,500+ Lumen per Square foot during vegetation
  • 10,000+ Lumen per square foot during flowering

Lets keep going with our first example to figure out how many watts wee need. So far we have a 3’x3′ square foot grow room that is perfect to 6 healthy plants.

(3’x3′) = (9′ grow room or 6 plants ) x (10,000lm Max) = (90,000lm or 150watt)

If the math is correct the real cost for LED grow lights shouldn’t be too much. When considering the electric savings and low heat output it is easy to see that LED are the best solution for small grow rooms, stealth grows and even commercial level set ups.

Know your Spectrum

Grow lights spectrum is a topic on to its own that deserves its own write up. We won’t get into the depths and details here, but look out for future articles covering this topic. For now lets just cover the basics.
All plants go through a natural light cycle that is part of its environment and the changing seasons. Its important to know how the seasons and natural light cycle effect and plant growth. Also how you can control the light cycle indoors to alter grow rates.

Visible Light Spectrum

Light is measured in Wavelength, the visible spectrum is within the range of 300nm to 800nm. This spectrum is all we are concerned about for growing. Any lighting source that can cover this range effectively is called “Full Spectrum” lighting.
Although being able to mimic the entire range indoors may be nice (300nm – 800nm). It is not really necessary for a good grow and high yields. Yes, the entire range is represented in nature, but its not needed for photosynthesis.

Maintain 400nm to about 750mn Light Spectrum for better yields

Light spectrum – Season – Growth Phase

  • 400nm to 550nm – Spring to mid summer – Vegetation
  • 550nm to 750mn – Mid summer to Autumn – Vegetation to flowering (budding)

Want to know more?: natural lighting and intensity.

Like stated above, most LEDs are power efficient and produce less heat than standard grow lights. But they are not all created equal! We need keep a couple of things in mind when shopping for LED grow lights.

  • Cost per watt
  • Life time
  • Spectrum
  • Lumens
  • Space required

CFL Color Temperature or Kelvins

If you are new to CFL or growing with florescent lighting, the concept of “Kelvins” may be new to you. Don’t let it confuse you, it’s really very simple.


  • LED grow lights are  actually panels that use an array of LED’s controlled by a chip. This array can operate a different light spectrum’s individually. This allows a single LED panel to cover nearly the entire visible light spectrum.
  • CFL grow lights on the other hand are single bulbs. Although its possible to control the intensity through a dimmer switch. CFL’s cannot operate at different spectrum’s, thats why best practice is the use of at least two different bulbs. One for the vegetative state, the other for flowering and budding.

“Also note, lumen and wattage is a separate issue that doesn’t effect Kelvins. For example a 60w bulb operating at 2700k has about the same lumen output as a 60w at 5000k.”

 The 3 Basic Color Temperatures

CFL Kelvins can be separated into 3 groups. These three groups represent the light spectrum they cover.

  1. Soft White: 2700k to 3000k represents the red side of the color spectrum. Equivalent to  600mn to 800mn wavelength in LEDs. (flowering)
  2. Cool White: 3500k to 4100k, the mid spectrum. Roughly equivalent to the 500mn to 600mn range wavelength. (vegetative)
  3. Daylight: 5000k to 6500k the bright white/blue spectrum. Roughly 350mn to 500mn wavelength. (Vegetative)

As you can see, it’s really a very simple concept. Because CLF are only able to operate within a strict color spectrum, some large scale growers prefer CLFs for flowering.

Best LED for growing one to three plants

If you are considering a grow of more than two plants, you should have a decent size growing foot print. Lets also assume there is plenty of head room. IT should be safe to say, your growing in a closet, tent or similar structure. That means there should be enough room to hold a decent sized LED and head room to raise and lower it if needed.

GalaxyHydro 300W and 600W
Even though there are so many good brands out there. GalaxyHydro produces the best small to mid size grow LEDs for the dollar.  Their lighting systems have withstood the test of time in durability, reliability, support and warranty.
Specs on both 300w and 600w

  • “Optimal-Spectrum” technology. Which they clam to efficiently cover the 430mn to 740mn full spectrum
  • Energy saving chip set
  • Fan cooling
  • 50,000 hour / 2 year warranty
  • 30 money back guarantee

Galaxyhydro LED 300w Review

Excellent low price for first time or personal medical marijuana growers. This was actually the first LED that I started with over 5 years ago. I still use it now periodically for cloning and haven’t had any issues since the first grow.
This LED is perfect for a maximum of 2 to three plants max. An lumen output efficiency of about 7000lm should be adequate for standard grow. If you have more space, are planning on growing more than tree plants, or using an advance grow technique, consider the 600W.
This is by for the best LED you can get for under $100, Here are the specifics:

  • Price: $80 / $.26 per Watt / .011 per lumen
  • Lumen: @ 7,000
  • Dimensions / Weight: 8.19 x 12.13 x 2.36 inches / 5.6lb
  • Power Usage: @145w draw usage, 300w light output
  • Operating DB: 55+ dB
  • Operating Temperature: Expect 75 to 85 degree, ambient temps not considered
  • Coverage: 10 sq.ft

 Best grow light for closet grows

Even though I have never owned this model, I would recommend it over the 300w. For just a few dollars and a little more space, you are getting double the wattage. Besides the price and slightly larger size, you may also be faced with a couple of limitations.

At 600w output you can expect a higher operating temperature. The actual power draw is about 230w. Model specs state temps of about 104°, but in confined spaces with little or no ventilation, expect up to 150°. More overhead clearance will be needed to provide better coverage and prevent issues.

Basically, you will need a larger area for this system. Regulated ventilation is recommended if possible, if not monitor temps. Here are the specifications:

  • Price: $150 / .25 per watt / .010 per lumen
  • Lumen: 14,000 estimated
  • Dimensions / Weight: 19.7 x14.2×5.5 inches / 12lb
  • Power usage: @230w draw, 600w output
  • Operating dB: ??
  • Operating Temperature: 100° to 150°
  • Coverage: 20 sq.ft to 40 sq.ft

Why use CFL Bulds for stealth grows

There are plenty of growers out there that can’t dedicate much space for growing, don’t want to spend much on equipment. For them a stealthy grow box may be the best bet. There are plenty examples out of growers using file cabinets and even computer cases for growing pot.
In order to keep your grow secret, a stealth grow box must:

  • Not leak light
  • Stay Cool
  • Draw to much power
  • Be a decoy

Because of the compact size, power consumption and ventilation are limited. Lucky, CFL grow lights provide the perfect solution. Easy to use and setup, don’t generate excessive heat, compact size and low power consumption.
To grow weed in such a small space requires a little more attention. You can’t just setup your stealth grow box and expect great yields. So do thorough research before getting fully invested. As far as lighting, you can use one or two types of CFL’s for maximum returns.
When growing with CFL bulbs, always keep a backup or two

Our CFL grow recommendations

I prefer a 2 bulb solution, one for vegetation another for flowering. This will not only give the best spectrum coverage but also insure you have the plenty of light for full budding potential.
Use a Light hood if space permits!


CLF 60w


For Vegetation: Apollo 60w CFL 6500K
This compact florescent bulb should provide more than enough light for up to 2 plants. Covering a “daylight spectrum”,  It’s made for vegetative growth. But by controlling light timings, you can use it through out the entire grow if needed.
The low wattage means it will burn cool allowing you to go hood-less. It also shouldn’t need much distance or clearance. Making it a very easy solution but, if you want bigger buds, a stronger bulb is recommended during flowering cycle.




CLF 125w


For Flowering: Apollo 125w CFL 2700k
The flowering phase will require light in a deeper red spectrum. A 2700k CFL works great for this. The “soft white” glow at powerful 125w will trigger a transition from vegetative to flowing state.
The high wattage would be enough to produce the best yields possible. As mentioned above, a hod or light hat will keep all all the energy focused on your grow.





For More info click here

Leave a Reply