The best marijuana grow lights

If you are planning on growing your Cannabis indoors, you most likely have already taken a look at the different lighting options available.

Every grower has his or her personal preference for the best indoor marijuana grow lights, and you have probably already received advice about setting up your own lighting system in one way or another.

But how do you know which grow light will suit you the best for growing marijuana indoors?

Under natural circumstances, the cannabis plant sprouts in the Spring grows over the Summer, then flowers when days become shorter and less light is available. The plant’s lifecycle is driven by the photosynthesis (wiki) process. It is sometimes referred to as the cannabis light cycle.

When growing indoors, you can simulate this process. With grow lights, you can maintain a light schedule that tricks your plants into thinking they should start flowering. Not only that you also control light intensity, the light spectrum, and other factors that help your plants grow.

What defines the best grow lights?

When talking about cannabis grow lights, two main factors are important:

  • Power consumption: Is your electricity network up to it, and can you pay the bill?
  • Cannabis yield potential: More light equals a bigger harvest.

So, the ideal grow light is efficient on electricity while generating a heavy yield.

Other factors that come into play are:

  • Light intensity: The lumens you expose your plants to.
  • Light distance: Too close to the canopy burns the leaves, but too far isn’t efficient.
  • Light schedule: How many hours of light are your plants getting during each stage?
  • Light spectrum: The color of the light required for different grow stages.
  • How many plants you have: Will your grow room be overcrowded?
  • Climate control: Those lamps can get hot.
  • Your budget: Some setups can be expensive.

With that in mind we’re going to look at what types of grow lights are available on the market.

Download my free Grow Bible to make the most of your grow room and lighting setup!

Type of marijuana grow lights
Different types of grow lights

What types of grow lights are there?

There are a variety of grow lights in the market, such as incandescent lights, fluorescent lights, high-intensity discharge lamps (HID), and light-emitting diodes (LED).

If you’re growing indoors, you’ll have to decide how best to set up your own lights. There are a lot of different options when it comes to the lighting system, and there are a lot of opinions, too.

When it comes to lighting, you have a lot of different choices. We covered some of the basics in types of lighting in the last section. In this section, we’ll cover more about the different choices you’ve been presented with, and discuss some of the pros and cons of the different lighting setups.

Many growers argue about which lights are the best, but, in general, every type of light specializes in a certain phase of growth or a certain type of job. It’s up to the grower to decide how much time and money they want to invest into their lighting systems.

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CFL – Fluorescent lights

In the early days of Cannabis cultivation, fluorescent grow lights were used by growers to simulate the sun, just as they had been used for many years by farmers and botanists for indoor growing and early germination in cold climates.

Unfortunately, fluorescent lights are expensive and you require a lot of fluorescents to simulate natural sunlight.

Not only that, but it requires a lot of different types of fluorescent lights to mimic the full spectrum of natural light.

Check the best CFL lights at this link

Nowadays, growers still use fluorescent lights when plants are extremely sensitive to heat.

This applies to cuttings and seedlings in the early stages of growth.

Keep in mind, however, that the fluorescent lights still need to be close to the plants themselves, usually about 5 cm away.

Fluorescent technology has changed somewhat, too, and now fluorescent lights offer slightly higher quality growing for Cannabis than they used to.

If you’re using fluorescents, you’ll also want reflectors to go with them, to maximize their efficiency and save yourself some energy.

CFL bulb for indoor marijuana growing
CFL bulb

HID – High-intensity discharge lights

High-intensity discharge grow lights were first invented for a huge scale, for use in public arenas and stadiums.

These sorts of light are very powerful, and they’re used by a lot of botanists and horticulturists to grow lots of things besides Cannabis.

But they do work quite well for Cannabis, so let’s talk about them.

Within the various types of HID light, we have:

  • Mercury
  • Metal halide lights (MH)
  • High-pressure sodium vapor light (HPS)

We’ll cross mercury lights off the list right away because their lumen-to-watt capacity is too low for them to compete with the others.

HID light bulb for growing marijuana
HID light

MH – Metal halide lights

Metal halide grow lights produce light by arcing an electric current through mercury gas mixed with some sort of metal iodide such as thallium, thorium, or sodium.

The light that it produces falls into a perfect range of the color spectrum for the growing phase of Cannabis.

In particular, it’s good for producing foliage.

Plus, it’s flexible: 1000-watt metal halide lights can be used to induce the flowering period in plants.

Growers in the United States used metal halide lights for a long time after the introduction of HID lighting, and they performed well for all phases of plant growth.

metal halide light
Metal halide light

HPS – High-pressure sodium vapor lights

In the mid-80s, when communication began in earnest about growing practices and how they differed in the US and Europe, growers, and cultivators discovered a couple of unusual differences.

First of all, Americans were using a lot more power than their European counterparts.

One of the reasons for this is that most Europeans were using horizontal reflectors and HPS grow lights, whereas Americans were using vertical reflectors and metal halide lights.

HPS lights have the ideal color range for Cannabis plants during their flowering phase while metal halides are superior for the growth phase.

They function similarly to other HID lights and create light by arcing electric current through a bulb containing xenon and sodium gas.

They emit a dull pink glow that quickly turns into an orange-pink light once it warms up.

HPS lights work spectacularly for indoor cultivation, especially for a plant going through the flowering phase of growth.

You can purchase HPS lights in a number of different strengths: 250w, 400w, 600w, and 1000w.

Don’t even think about using the 1000w light unless you’re growing a whole field in an underground bunker.

In order to take advantage of the strength, you have to cool your grow room with an air conditioner.

Your best bet is to purchase two 400w or 600w HPS lights: these will evenly diffuse light for your plants, and they aren’t overly lot so you have a low risk of heat damage. 

Keep in mind that you might want to use a fluorescent light in conjunction with your sodium vapor light.

‘Agro’ type lights are also a good choice. Made by Philips, the ‘Agro’ light slips into the blue spectrum, and the lights are easy on the pocketbook.

You can expect to replace lights about once every year if you have them running a lot.

hps high pressure sodium vapor marijuana
HPS lamp

LED – Light-emitting diodes

Can you use any LED light as a grow light for my plants? No, not any old LED light is suitable for growing weed. To ensure that your plants are receiving the optimal light, you have to make sure that it is coming from a full spectrum LED, which comes from the best LED grow lights.

LEDs (light-emitting diodes) have become ubiquitous in the lighting world over the last decade.

While not necessarily the ideal light for growing cannabis, LED lights offer several advantages.

First of all, they are low voltage, which means less money is spent on upkeep and electricity to keep them running.

Coupled with this, they produce very little heat, which means you don’t need to worry about overheating your grow room if you use LED lights.

It also further reduces your reliance on ventilation and fans, adding even deeper energy savings.

In fact, depending on your operation, you may very well need to heat the room if you are using LED lighting.

For growers prioritizing privacy, LED lights offer an additional bonus— the low heat makes LED lighting virtually impossible to detect with thermal imaging techniques commonly used to spot the infrared heat of more conventional HPS lights.

LED lighting is also quieter than the other lighting options, without the background hum emitted by HPS lights.

Remember that not all LED lights are created equal! Be sure to check your bulbs and make sure that they are high-wattage and have a high lumen value.

The higher these are, the brighter your light will be.

You also want to make sure that the LED lights you choose have been specifically manufactured to emit light at the full spectrum of color your plants need for proper photosynthesis.

LED lights do have a higher initial investment than some of the cheaper options, which can cause some growers to be skeptical about using them.

Then again, they are very efficient. LED lights waste far less energy as heat, assuming the room doesn’t need to be heated, and those savings on electricity will pay for themselves in just a couple of years.

You also don’t need to worry about setting your grow room on fire, and LED lights last for a long time.

Some manufacturers advertise more than 100,000 hours of life in their LED bulbs, which gives you enough time for almost ten years of harvesting.

Growing weed plants indoors and using grow lights
LED lights for growing cannabis

What grow lights do you need

Lighting systems will vary in intensity, spectrum color, and the underlying technology.

It will come down to the size of your grow room, your electrical needs, and how much time and money you’re willing to invest into lighting up your grow room.

When you choose a light system, first plan on how much light you need to use, then compare that to how much light you can realistically provide for the plants.

If you live in an old house with a direct current, it probably won’t be much!

Be realistic, and remember that lights use up a lot of power.

The real key to deciding what sort of light you need is to figure out the size of your grow area.

If you’re using an area that is smaller than 5 square feet, consider using a fluorescent or HPS 250w light.

Fluorescent lights are small, and they will help your cuttings root well. Later, as plants get large, you’ll want an HPS light.

Ideally, if you’ve got the space, you should use a metal halide light when your plant is in its growth phase and an HPS light for the flowering phase.

If you use a metal halide light for both growth and flowering, you’ll be ok, but your plant will have more foliage than necessary and not as many flowers.

This means you’ll have a lower yield.

If you use an HPS light during the growth and flowering periods, you’ll end up with a plant that is long but maybe not as structurally sound as you’d like.

If you only have space or time to use a single light, consider using one of the ‘Agro’ types of light.

Above all, be smart about using what you’ve got. It’s important to have lighting, but you need to plan it out, too.

You can’t just fill a room with ultra-high-wattage lights and expect your plants to thrive.

Don’t waste valuable power, and learn how to make use of your resources.

Thanks for reading. Please leave comments or questions below and don’t forget to download my free Grow Bible!


Avatar for Robert Bergman

Robert Bergman


Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations ... See profile

67 comments on “The best marijuana grow lights”

  1. I have a set of flexible grow lights red and blue. For Hydroponic Indoor growing. Do you think they would work well for growing marijuana??

  2. I don’t see anything about cmh? Iruna 630 and 600wr vispectra In middle and a 315 cmh woth on plant under that one well 7 plants total in a 12/8 room.

  3. What Kind of kind of light would you suggest for growing in a small 3ftx5ft closet. I want to use a LED that i can switch from veg to flower.Only going to
    have two plants in there.

  4. John, Yes No Idea What You Are Asking. Perhaps Go Here And Share You Thoughts: Support.Ilovegrowingmarijuana.Com

  5. Arthur, It depends on your grow area. I Suggest You Go Here: Support.Ilovegrowingmarijuana.Com Our Members And Staff Can Help Give You Informed Advice. We Have A Lot Of Topics That You Can Research.

  6. Arthur, The acidic nature of milk will help you contain powdery midew. Mold thrives in an acidic environment. On house mold I spray a baking soda mixture and it dies over night but, this would not be recommended for Cannabis in flower. If I find mold in my grow; I usually prune it out or cull the plant and accept the loss.

  7. Newbie here…..can you grow from seed to harvest an indoor fem autoflower (WW) with just one kind of light and still get good results?

  8. Second week in flower phase and my plants have grown up into my light which can not go up any higher in the tent. Should I top them off or tie them down?

    • Tie or break them.

      I suggest you join our forum. The blog is not set up to do continued grow support 🙂 See you there

  9. hello . i wanted to now that is a 400w mh(for vegitat) and a 400w hps(for flowerin) is ideal for a 200cmx80cmx300cm place or its low . im very confiusd pls help

    • 78″x32″x10′ Is this right? Or; Is there a typo in your cm? What you posted would be 6-1/2 feet by 2-1/2 feet by 10 feet tall. Never saw a tent like this.

      1 400 for veg would cover a 3′ x 4′ (91cm x 121cm) That is the footprint for 1- 400 watt lamp. Always find the footprint of the lamp you want to buy and go from there to cover the entire floor of you grow space.

      Hope this helps 🙂

      • its a Balcony i coverd it with plastik and foil . the length is 200cm(2meter) the width 80cm and the hight 300cm .
        what does footprint mean in lamps ?
        many thanks for the reply

      • Footprint = the imprint of the light on the floor or at canopy height. i.e. Where the light shines as opposed to beyond the hood where the light gets cut off from direct light

      • its a Balcony 🙂 i coverd it with plastik and foil . the length is 200cm(2meter) the width 80cm and the hight 300cm .
        many thanks for the reply

  10. ILGM – what are your thoughts on the INDA-GRO PRO-420 light and a set up using the INDA-GRO 420 light in conjunction with a full spectrum LED light

    • lilchange,

      Yes you can as long as the lamp is 4-6 feet above seedlings.

      It is not recommended. You would be better off investing in a nice T5 lamp system for early veg. Once they are a foot tall, they can safely be placed under High intensity lamps

    • Joe – LEDs are not standardized like other lighting types and therefore vary greatly. The quality of the light and LEDs used as well as the wattage (total true watts, not equivalent wattage) and the angle of the lens (90° lens recommend for optimum focus and light penetration) will all determine the distance between the light and plant canopy. You also have to consider the light’s footprint and the size of your space (if separate veg and flower modes, go by the max coverage area for flowering). As a general rule of thumb though, 12″ – 18″ from the plant canopy is a good height. You should always chech with the manufacturer though to see what they recommend and then adjust the height if need be.

  11. diesel ,

    You will be able to grow successfully with all thjose little lamps. You will have to temper your expectations for yield. Plants will not flourish as well under those l;amps due to lack of light penetration and intensity. I would look into a 400-600- watt Iposer system. It is a switchable digital ballast with hod and lamp bulbs included.

    Happy growing

  12. Autoflowers can be grown insife or outside. Of course; Oudoors in never going to have a light cycle much longer than 14/10 in mid summer.

    Indoors most growers use 18/6 for autoflowers in order to maximize yield using the longer photo period.

  13. […] The beauty of HID lights (like MH/HPS lights) is that they are tried and true, having been used by indoor marijuana growers for many years already. We know they produce great results — there is no question about it. They are also a very practical option. While CFLs don’t provide much in the way of convenience when it’s time to upgrade your growing area, MH/HPS light fixtures make it easy to do. Better yet, these lights are some of the most efficient lights on the market (maybe excluding some cutting edge LED lights). […]

  14. Hi! This site is wonderful. Growing white widow autoflower. My question is this: I understand that as soon as the plant emerges it emerges in the flowering stage. Therefore, what is the best light for an autoflower light. Just growing 2 plants in small space. Your thoughts are greatly appreciated. Thanks, Terri

    • I dont think you need a light schedule , it aready comes modified to flower on any light schedule,but 12-12is the ideal light schedule!!

      • In a closet space of 3x7x8 thinking of using 8-23 watt cfl and two t5 fixure in each corner using t5 54 watt is this a bad or good idea or do I need to do something different

      • I have a box 4.5′ tall 3 ‘ wide 2’ thick I run one full spectrum led at 100 watts @35 volts . it runs bright pink . I measure air at 79 to 80 degrees the soil is 82 degrees at 10 inches above is just fine be brave and go 5″ keep the air moving not blowing directly on the plant no its banggood app look up full spectrum led chips

  15. […] The buds themselves should have direct exposure to the light for best results. Read more about Marijuana grow lights if you’re growing […]

  16. I was just re-reading your paper on lighting and I wonder, since this article was written on 18 June, 2012 if you have had any other thoughts on LED”s since they have greatly improved since that date. I am using 2 of the Advanced LED Lights 300 watt XTE series (sorry, I bought these before I knew you were hooked up with Dealzer) and I love them. Just a passing thought. Have a great day. Keep it green.

    • Robert, I am a new grower and I am researching and experimenting as I go. I am currently using the via par spectra 600 which has built-in fans and lighting for all stages. It suggested in the pamphlets that I use the lights with the lights on for both growing in flowering. So I just turned all of the lights on and have them approximately 30 inches above the plant however I read another article by you that you suggested it be a lot lower. I’ve also read articles on temperature where it suggests that running a hotter grow room is better for the plants however I read an article by you where you suggest that the temperature be loweredand you gave some great ways to check the temperature in your grow room. Do you know if there is a way for me to contact you or someone at your company for some assistance. After much research I resolve that your website and your company was the company I wanted to do business with unfortunately I had problems purchasing seeds from your company because I live in America and something to do with banking I have since work is through most of those problems unfortunately I purchased some seeds from another company. Again my goal is to use your Company moving forward. I appreciate what you and your company do and think that it brings value to your customers and I believe that your company cares and I think that that goes along way and what we’re trying to accomplish. Rather than putting everything on an email I was wondering if there was a way for me to contact someone at your company. Thanks again for all you do and I will look forward to an email mail from you or someone at your company take care and God bless

  17. Honestly, As a new grower; You probably should invest in digital switchable ballasts. 120-200 bucks for an entire (400-600 watt) system including MH and HPS lamps, hangers, and hood. Everything you need. You can but 2 or 3.

      • Have you looked in the Official buyers guide at the ILGM grow support forum. I have placed links to these products on Amazon, for you to choose from.

      • Brock,

        I suggest an Ipower system. Ipower digital systems come complete with all you need. Available on Amazon.

      • im using the Ipower 600watt dimmable and switchable digital ballast and its a complete combo for around $250 or under shipped to your door, i like it as the ballast stays very cool and has its own fan built in, sure the bat wing reflectors abit cheap but works in my smaller area

  18. Robert
    Have you used or do you know anyone using the new Dimlux expert series 1000 watt double ended bulb lights ,if so what is your thoughts on them and how do you set them up .
    My hydro shop says you put them right at the top of your tent and let your plants grow into them, I think this will cause streching not what I want what do you think.

    They expensive too $ 1100 per light plus controllers and sensors.

    Hydro shop says they do a 2 meter foot print this I don’t believe I was thinking maybe two of these lights on a mover in 8x8x8 tent please give me some advise as I can find any review on the Internet regarding these lights

    Thanks pete newbie

  19. […] The more leaves your cannabis plant has, the more light energy it is able to receive, therefore it will be a greater powerhouse generating more energy. The thing is your plants don’t just take any source of light. A certain type of light is necessary. The strength and specific color of the light matters for photosynthesis to take place accurately. For instance, blue light is necessary during the growth process and once it is time to start blooming, your plant needs red and orange light. There are unique lamps that exist just for this purpose. Read more in the article Best marijuana grow lights […]