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how many lumens needed to grow cannabis

I have 3 bulbs in there CFL
2700+1700+1700 lumens = 6100 lumen

hmm. I think I may have mis-interpreted what herball was saying or he may have wrote it wrong.

Remember, it’s not a contest: We all love the same plant, and there’s hundreds of ways to grow her right. Arrogant growers love to put down other people’s nugs and argue for days about why nobody can produce better pot than they can. These types actually end up infusing some of that negative and competitive energy into their plants. – Unknown Author (High times)


I have 3 bulbs in there CFL
2700+1700+1700 lumens = 6100 lumen

flower phase: when you switch to flower go 11 hours and then every two weeks reduce the light by 30mins and when you get to about 9.5 hours just let the kids finish up that way. (this mimics nature and performs better). if your plants won’t finish budding. whatever cycle your using, drop the hours and the plant will do better and finish up.


hmm. I think I may have mis-interpreted what herball was saying or he may have wrote it wrong.

I cannot quite understand how he has put this.

How many lumens needed to grow cannabis

Thanks for reading everyone and remember: Grow… And help the world grow, too!

In a smaller home grow tent, the best light solution is a 400-watt HPS set-up. (Photo by Nico Escondido)

Of course, bulb manufacturers and garden shop sales people will tell you a 1,000-watt bulb covers anywhere from 6’ x 6’ t0 8’ x 8’, but that is not based on photosynthetic processes but rather on physical light coverage (hence the use of lumens and not PAR).

A good example of this is the fact that many bulbs are still marketed using “lumens” as a selling point. While lumens are a measurement of light quantity, it is not an appropriate term for horticultural purposes.

Greetings to you, Nico!
I have searched the web and noticed that you are the guy to ask about indoor lighting for cannabis horticulture. My question is rather simple, I think: In terms of lumens, what light output do I need to grow a plant or two successfully in my home? I have a small bedroom and am thinking of using a ’ x 4’ or 4’ x 8’ grow tent? Any suggestions on bulb types and strength would be helpful! Many thanks & good luck to you! — Jonathan V. via the mailbag at [email protected]

So while a 1,000-watt bulb may seem plenty sufficient for a 4’ x 4’, it will be too much light. In a 4’ x 4’ x 8’ tent with no exhaust, a 1,000-watt bulb has the power to raise the temperature nearly 25 degrees in no time. That means 68°F can climb to over 90°F! Even with ample exhaust, you’d be hard pressed to keep temps below 80°F.

LEDs could pose an alternative in the future, but right now, LED companies like this one are going belly-up after coming to market with a $1,400 price tag. (Photo by Nico Escondido)

Lumens would be used to describe the strength of light if you were trying to light a stage or illuminate an object for viewing purposes. However, for photosynthetic purposes, the proper quantification of light uses PAR values, which stands for “photosynthetically active radiation.” This measurement of light provides information on both the quantity and quality of light being emitted by a source in relation to its effectiveness and efficiency for the plant’s photosynthetic processes. It takes into account not only strength, measured by photon count, but also spectrum, measured by color or wavelengths.

Deciding on light setups for any indoor garden can be a daunting task. The horticultural lighting industry almost feels like it is purposefully trying to confuse us sometimes, possibly in the hopes of getting consumers to purchase more items—or more expensive items—than we really need.

Thank you, Jonathan, for reading and writing in with an excellent question!