Growing Cannabis – Where to Start

If you are just starting out growing cannabis indoors, there are some things to consider when choosing to buy LED grow lights onlineThe first thing you need to ask yourself is how many plants do you plan on growing. This will tell you which light or combination of lights that will be needed.
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How Many Plants Can I Grow?

Growing Cannabis Plant ChartTo find out how many plants you want to grow, you need to determine the amount of space you have or want to work with. Indoors, the average amount of space per adult plant will be 2.5 square feet. This can vary based on the strain you plan on growing as well as the method you intend to use for cultivation.

For example, if you intend on growing cannabis like a Sativa-dominant hybrid with the ‘screen of green’ (SCROG) method you will need a bit more space since Sativas grow larger and the SCROG method redirects the growth of the plant more outward than upwards.
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How Much Power Do I Need?

So once you determine your area by the number of plants you want to grow you need to determine the total wattage of light(s) that you need. For optimal growth, you will need 50-60 watts per plant so 1 plant = 50 watts. 2 plants = 100 watts, 3 plants = 150 watts, and so on.
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What is a Footprint?

Par Footprint MapThe next thing you need to look at is the area the light can cover also known as its footprint. Standard 300 watt grow lights for cannabis will cover an average of 4 square feet, a 600 watt will cover 5 square feet, a 900 watt will cover 6 square feet, and 1200 watt will cover 7 square feet.
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The area is measured by placing the light at 18-24″ of height above a flat surface or your proposed canopy. Please note that footprint for higher powered lights are larger because the light needs to be placed further from the canopy to prevent bleaching of leaves.
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The spectrum of light will be most concentrated directly underneath the light and as you look further out, you will see the light dissipate. The region that is receiving adequate light is what’s representative of the lights footprint. Anything outside of this range is not getting enough light to grow cannabis to its full potential resulting in a lower yield.
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If you attempt to grow in these outer areas, you will see a lot of stretching or there will be little growth at all. When the plant is stretching, it is focusing its energy on growing towards the light instead of other more important functions like building strong roots, stem, branches and ultimately bud production.
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Can I Get More Light?

There are ways to redirect some of the lost light at the wider angles back onto your plants’ canopy like using the mylar in a grow tent, mirrors, and reflectors on grow lights which can make a significant difference in growing cannabis. This is mainly to be taken into consideration if you don’t have enough coverage from your light or if you want more light in the outer areas.
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What Are PARs?

Grow Light for Cannabis SpectrumPAR measurements are the most important factors in determining a LED grow lights usability but there seem to be many different schools of thought when it comes to the intensity of light needed for growing cannabis. You will see the term PAR addressed by many LED grow light manufacturers which reference the intensity of light but this unit, though most important can be a little bit misleading.
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This is because of the use of secondary optics which focus the light at a lesser angle. By reducing the angle the PAR is increased resulting in a higher measurement. The only problem with this is it reduces to footprint significantly. So, the higher the PAR is not always better.
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Is The Color Of Light Important?

The type of light produced is very important when growing cannabis plants. The two most utilized colors for photosynthesis are Blue (430nm-450nm) and Red (640nm-680nm). Other colors like yellow and green help aid in the plant’s architecture but most of which is reflected.
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Experts suggest you split the light concentration for the vegetative stage to 40% Blue and 60% Red and for flowering stage, 30% Blue and 70% Red. This allows optimum growth for both stages of the plant’s life cycle. This change in spectral output can be accomplished by a veg/bloom switch, a dimmer on your chosen light, or with the addition of another light.
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Full Spectrum Lights

Color Spectrum for Growing CannabisThere are lights that produce what’s called a ‘full spectrum’ and these lights are excellent in that they produce a light that is more similar to the sun. Though not mandatory, it’s always a good to get as close to the sun’s spectral output as possible because that’s what the plant has evolved to absorb.
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Conclusion

So, what have we learned? First, we determined how many plants we wish to grow, then we figured out that each plant will take up an average of 2.5 square feet of space. We also learned to look at the area or footprint of the light to determine whether it might be a good fit for the number of plants we intend to grow.
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Something else we learned that a lights PAR measurements can be misleading depending on whether or not the light has secondary optical lenses. Lastly, we learned that full spectrum lights are good but not mandatory for growing marijuana and blue and red spectrums of light are what plants utilize most.
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If you need any ideas on which lights are among the best, I recommend that you look at the grow lights for cannabis that I have tested and reviewed here. I definitely have one that will work for you and your specific needs whether you are growing cannabis, fruits, vegetables, or house plants. If you don’t see what you like just leave a comment at the bottom of the page and I’ll find a light for you that’s within your budget.
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If you have any questions or have any comments on the subject, please leave your question or comment below and I will respond right away. Thank you for visiting and I’m glad to be able to help you.
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14 Comments

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  1. Jack Brandon Dockery

    This is a great article! I’ve seen tons of movies and shows where people grow in their own houses and I’ve been curious about how they figure out the appropriate amount of lighting. I live in Florida and last year we voted to legalize medical marijuana and I’ve been considered dipping my toe in that water. How significant would you say the change in your power bill has been since you’ve been growing?

    • Karl Hosch

      It’s a good idea to grow your own because you get to reap the rewards in the end. Plus there is something very fulfilling about growing your own plants that is hard to put in words. As far as my power bill, we’ll, it’s hard to say because I’ve grown single plants to entire crops so the difference can be substantial. More times than not you can expect LED lights to run at 1/3 the cost of traditional HPS/MH lights which is huge. How your bill will be affected depends on how many plants you intend to grow which determines how many light(s) you will need. I hope that answers your question. If you need any help with your grow, let me know and I’ll do my best to help you out. Thank you for stopping by. 

  2. Tyler Redlev

    I read your article with great interest!! Exactly what I wated to find on the internet.

    Growing my own cannabis is one of my personal goals (and not probably just mine 🙂 ) and I was looking out for a system that I can come up with to near automatically grow them with light system specific to their needs during their growth period. Do you have any technology or some product to advise me which can help me with this issue??

    • Karl Hosch

      As far as automation for growing cannabis….. It’s possible but it could be a little pricey. You’d still need to check on your plants often to assess their health and address any areas of concern but sure it can be done. You can build your own watering system on timed watering or have hydroponic setup. You can also have your lights set up on timers with veg/bloom switches for the different cycles. With LED lighting you don’t have to worry about excessive heat but I’d keep the air flowing with a 4-6″ fan which can also be put on a timer. So yes, it can be done but no matter what you will have to perform some maintenance and checking on you plants. Let me know if you need any help setting up your system! Take care! 

  3. Brendon

    Great article! I do not have a green thumb in anyway and all of my attempts to grow have failed. You have helped me a ton here, like I had no idea how important the color of the light is.
    Can the plants be moved indoors and outdoors to get natural light? Does this help them grow at all?

    • Karl Hosch

      I never had a green thumb before either but a lot of research and getting my hands dirty changed all that. Yes, the plants can be taken outside to get sunlight but you have to be careful because that’s where pests can be introduced and if there is a big temperature difference it could send the plant into shock. Plants grow best with consistency. If you keep the climate and environment the way they like it, they will return the favor by providing high yields. Thank you for your comment, if you decide to give your green thumb another try, just come back and I’ll help you any way I can. Cheers! 

  4. Daniella

    Hi there,

    Great article!

    I always wanted to grow Cannabis plants in my house, but I didn’t have a clue how to do it. This article explains well all the steps we need to do, and I thank you for this!
    I am amazed that blue and red light help the cannabis grow up. I thought yellow would do the job:)
    Just a question, please. Is it allowed to grow Cannabis in all countries? Or should I get permission, first?
    Also, I didn’t see any link that leads to the light. I would like to check the price. Can you suggest, please?

    Thank you for this excellent post!

    • Karl Hosch

      Yes, red and blue are the most utilized colors in photosynthesis but you wouldn’t know it because the sun is actually all colors of the spectrum plus some others we can’t see. Cannabis is not allowed in all countries so it just depends on where you are at. It’s best to check online whether your location is legal or not. As far as the link goes, at the bottom of the page there is a ‘next’ icon which would take you right to the lights. If you have any questions on choosing a light, feel free to ask and I will answer any of your questions. Thank you! 

  5. Alex

    As a college student low on cash, I have thought about growing on the side to make up for it, but I always thought it was too complex for me. After reading your article, I found that not to be the case.

    I do have a question though. Among all the LEDs on the market, what would you recommend I get? Thank you in advance and I hope you have a wonderful day!

    • Karl Hosch

      Even on a tight budget there are plenty of options. What you need to determine up front is how many plants you intend to grow, from there you can choose your light or lights. The best budget brands are Meizhi, Viparspectra, and Galaxyhydro, in that order. These lights have a good track record for performance, efficiency, and longevity. If you are able to splurge a little bit you can do better with California Lightworks or Advanced Platinum but either way, you’ll get your money back possibly on your first grow. Thank you for your inquiry and I wish you much success if you decide to grow. Come back and see me anytime if you need any help. 

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