Marijuana Grow Lights

… which ones work best and where to buy them?

Always remember: Light == Weight!


Further below: Details for all lamp types and where to get them.

When you grow cannabis, you will put your plants initially under 18 hours of light. For the remaining 6 hours they need total darkness.

This 18/6 hours period is called “vegetative stage”. The plant thinks it is spring. It puts its energy into leaf and stem growth. It will not develop buds.

After 2 – 4 weeks of vegetative growth, you are going to switch the light to 12 hours on / 12 hours off. This will make the plant think that it has become middle/late summer. Time to develop buds!

If you have decided to use different light bulbs for vegetative / flowering stage, now is the time to change them.

If you want to avoid stress for your green friends, don’t switch the light radical from 18 hours on to 12 hours. Go 2 or 3 days with 16 hours / 8 hours and 14/10.

Switching on and off is done by a timer. Not manually. Because otherwise one is likely to forget about it.

(Tip: Click the product images to go to eBay and see pricing)

CFL Grow Lights

Easy to use, for an alright harvest with not too much electricity used.

CFL Quick Tips
  • 2700K = Flowering, 6400K = Growth
  • Not as much light as HPS lamps, but easier to use and not as much heat
  • You can mix 2700K + 6400K and use it through whole grow period
  • Keep them close to your plants for best results
  • You could use 1 x 2700K bulb for whole grow (Cheap Micro Setup)
  • 1 x 150Watt is ok for 2 – 4 plants

150 Watt CFL with Reflector


250 Watt CFL + Reflector


T5 Fluorescent Sets



Pic of mature Sticky Icky MarijuanaCFL Lights are relatively inexpensive. They are easy to use, just plug them into a timer and then the outlet.

They don’t produce too much heat and thus don’t require much ventilation.

And yet, they still yield impressive results.

Available in different colors. 6400K for vegetative phase and 2700K for Flowering.

For a very small setup, just one of these in 2700K with a reflector will do for the whole plant life.

You can get good results by using 1 x 2700K and 1x 6400K at the same time.

Pics of Weed grown under CFL Light:

IMG_0284

IMG_0257

HPS or MH Lamps

High Pressure Sodium or Metal Halide bulbs deliver fantastic light for Cannabis.

These are slightly more expensive but deliver a lot more light per Watt.

HPS & MH Quick Tips
  • HPS can safely be used for veg and growth phase
  • MH = Growth phase only
  • These produce more light than CFL
  • Produce heat. Ventilation needed
  • 1 x 400W HPS is good for 6 – 8 Plants

HPS are recommended for beginners. You can use them through the whole plant life.

If you want to do a perfect Job, you could get an additional MH bulb for vegetative stadium.

Complete HPS or MH Set


Cost efficient reflector
in 250 Watt, 400 Watt (best option) or 600 Watt

For better quality get DIGITAL system. Listed here.


These lamps come with a Ballast to run them. Do yourself a favor and get one with a digital ballast. They use less electricity, produce more light and the bulb lives longer. Also, they throw less electro-smog. So the digital ballast is very recommended as opposed to the old dirt magnetic ones which are still being sold every now and then.

Get a 250 Watt for a small setup, 400 Watt for average or 600 or 1000 Watt if you want to go above self supply.

I recommend 400 Watt. It produces lots of weed while not overly stretching the electricity bill.

Pics of Marijuana Grown under 400 Watt HPS:

Bud grown with 400W HPS

400 Watt bud

Delicious Buds

Marijuana Grown under HPS lamps looks a bit more “Professional” than the same grown under CFL It is denser and has more volume.

HPS and MH Lights can be bought on eBay here.

LED Marijuana Grow Lights

Led Grow lights can produce great harvests.

LED Quick Tips
  • These can produce great results with little electricity
  • Produce little heat
  • Fake units very commonly sold. Watch for original brand LEDs (e.g. US made CREE)

They are still expensive, but use very little electricity.

Currently, a lot of people sell these with outrageous claims like :”Replaces 400 W HPS” … or so.

That is most often not true. Especially cheap ones on eBay, they don’t really work.

LEDs have big quality diferences. Additionally, brand names are widely faked.

Genuine CREE LEDs seem to be the best. But, they are often faked. It’s important to check the sellers reputation.

Underneath are links to an eBay seller who seems to produce LED grow lights himself. I trust his lights to be genuine.

Also, I have found a remarkable LED Grow light from an engineer in Holland. His name is Hans and he builds, in my opinion, the worlds best LED Grow light.

It cost as much as 4 large HPS lamps. So it is a bit like a Rolls Royce car. It uses quality LEDs and has a switch to change it from vege to flowering phase.

240W LED Grow Light

Small 100W LED UFO

Big 1546 Watt LED


Pretty Powerful system + UVB
Seems like a quality item.

Hans’ LED Light

Hans LED Grow Light
fantastic quality, switchabe for vege and flower.
Bit difficult to buy from Hans but worth it.
More info


Marijuana grown under  Hans 160 Watt LED Light

Marijuana grown under LED Light

Marijuana Grown under 160 Watt LED Grow Light

LED Grow harvest 3.8 ounces

This grow yielded 3.8 ounces (110 gram) for the price of $15 electricity.

2 LED Grow Panels

2 LED grow panels with 80 Watt each. No big fan required because there is not much heat.

LedGrowPanel hanging with fan

LED Panels are modern, silent, cold, beautiful and energy efficient but expensive on initial purchase.

So which Light is best for me?

If you are on a small budget, or have only little space available, or just want to grow a little weed for yourself: Use CFL Lamps. They are easy to use, inexpensive and produce decent results.

If you have a bit of space available, like a pantry or your garage, you could go for HPS Lamps. They produce big, but you’ll need a fan to get rid of the heat and may also need to filter the smell with a carbon filter. Read more about building a grow box, if you like.

If you are settled and have mastered the game of money. Or if you are generally into new and fine things, try Hans LED panels. You’ll have a silent grow box that uses little electricity and yet produces big yields.

Grow Light in more Detail: Light Color

As mentioned earlier, diferrent light bulbs have diferrent colors.

Plants in vegetation mode need more blue light. MH Lights provide that. MH lights even deliver some red light which makes it possible to use them over the whole plant life.

Flowering plants need more red light, as supplied by HPS lights.

The CFL Lamps are available in red, blue and mixed colors.

Light Color (also called light temperature) is described in Kelvin. 2700 K is a very red spectrum for flowering. 6400 K is a cool blue/green light, as needed for growth. There is also 14.000 K available which has even more blue.

Light Color Temperature Table

Used for Kelvin Color Name Color
Growing around 6400 Daylight, Cool blueish
Flowering around 2700 Warm yellowish – redish

Types of Lamps and their color.

There are High Pressure Lamps, Compact Flouro Lamps and LED Lights available. They all have their strength and weaknesses.

High Pressure Lamps

These are the (still) most commonly used Lamps.

Their brightness and good light color bring great results as Marijuana Grow Lights.

However, they also use a lot of Energy (200 – 600 Watt) and produce a lot of heat. Strong ventilation systems are needed. High Pressure bulbs also need a balast to start them up.

High Pressure Sodium Lights (HPS).

Marijuana Grow Lights

High Pressure Sodium Lights emit an orange/red light. Cannabis needs this during the flowering stage.

These Bulbs have a lifespan of ca. 24.000 hours.

High Power Grow lights

Metal Halide Lights (MH).

Marijuana Grow Lights

They send out light in the blue spectrum, which is used in the vegetative (growth) stage of plants.

These bulbs also emit some red. Therefore they can be used for flowering, too. They will yield a good harvest. These bulbs are the best option when you decide to grow under high pressure bulbs.

One disadvantage of MH Lights is their relatively short lifespan of only 10.000 hours.

Compact Fluorescent Lamps (CFL)

Marijuana Grow Lights

A very inexpensive but good option is the use of Compact Fluorescent Lamps (CFL). As shown on the left.

The bulbs are fairly cheap. They do not need a ballast. They run relatively cold

One Lamp with at least 100 Watt will be enough for 1-2 plants. Better use 2 CFLs.

They are available in diferrent colors for vegetative (6400K) and flowering stage (2700K). I had success even with using only one flowering bulb for the whole plant life.

Compact Fluorescent Grow Lights

ctor (except with LED lights) for more efficiency with your Marijuana Grow Lights. Very recommended.

Learn how to build your own Grow Box

  • Tricia Clemons Epps

    Hi Jack question what type of h2o do I need for starter up? I’ve been reading about RO water but I don’t know, can I use spring water or tap water? also, when do I need to check the ph on these ladies..thanks

    • http://www.how-to-marijuana.com Jack Tambo

      Hi,
      Spring water for seedlings will be good.

      Later for the bigger plants, that may not be practical since you’ll need a lot. Then any filtered water will do.
      Tap water unfiltered is not great due to the chlorine in it (depends on where you live).

      But generally, the better the water, the better for your plants.

      PH-checking is not 100% necessary for beginners, but if you do it start now.

      Potting soil, the best you can find. Usually some made for flowers. With starter nutrients in it. The better the quality, the better your plants. I get mine from the hardware store and I look for the best quality.

  • Steve

    Hi guys
    I’m very very new in the growing thing and is not sure if I have green fingers or not. My space is very limited and I’ve setup a small bed cupboard for testing. I’ve got the cheapest seats what i could find and plant it under E14 energy saving daylight bulbs. Im running bright daylight and blue on 18- 6 hours and as soon as im ready i will switch to daylight bright and red light on 12- 12 hours. Is there any advice for a small grower like me? I have 2 plants and did took the male plants away early.

    • http://www.how-to-marijuana.com Jack Tambo

      Hi,
      thanks for the images.

      The plants don’t look well. They are not growing as they should. At this stage, they would usually be much higher and have more leaves.

      Your light is not strong enough. Is there a way you could get either some more of the bulbs you have (you need 5 or 6 at least).
      Or better, buy a large 125W CFL instead?

      Jack

      • Steve

        Hi jack thank you so much for the info. I will definitely going for stonger light. The problem is I’ve started outside and replanted it 2 days ago. I used Dynaroot in the process and just started to water with 3:2:1 (22) . So its under the light for 2 days now. Do you think i must start all over with new lighting or just ad light and hope they heal.? Its winter now here in south africa cape town so had no choice to replant. Any advice will help me a lot. Thanks alot

        • http://www.how-to-marijuana.com Jack Tambo

          Hi,
          I think you must restart with a better light.

  • http://www.plasmagrowlighting.net/ Chris Pieser

    Hi, would you consider updating your article to include Plasma Grow Lighting? We have six years of doctorate level research to share with your readers if you are interested.

  • http://www.how-to-marijuana.com Jack Tambo

    Hi again!

    Yes, I can see what you mean.

    HPS brings great plant grow and harvest, but will throw a lot of heat and you will need more ventilation.

    A good LED light these days can bring similar results to HPS but it’s expensive.

    The problem with LED is, there is a lot of sales talk and lying happening. Some sellers say their LED lamp is equivalent to a 400W HPS. That is possible, but such LED lamp would be expensive. Also, lots of fake LED lamps are being sold (fake CREE).

    So I always recommend Hans’ LED lamps. Its an engineer in Holland who has made this one. It’s the best LED lamp I have seen so far. And he actually shows results. These are the harvests he gets: http://www.ledgrow.eu/test17.php
    and this is the lamp: http://www.bonsaihero.com/index.php/ledgrow-led-panel-70-w

    So yeah, I’d go for Hans’ LED.

    Cheers, Jack

  • Carter

    Great article! Thank you for the info…it helped me make sense of my options for sure!
    I would love more info on that Dutch engnieer’s work. Any chance you could provide that, or a link or something?

    • http://www.how-to-marijuana.com Jack Tambo

      Hans’ website: ledgrow.eu

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