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how many lumens needed to grow cannabis

It basically comes down to this, the more lumens cast over your grow area, the stronger your cannabis plants are going to grow. Each plant will require an absolute minimum of 2,500 lumens. A standard 400W HID lamp will usually emit 45,000 lumens. This should be enough to comfortably grow up to 12 cannabis plants in a 1m2 area – with enough lumens to cause strong growth.

Whilst have 45,000 lumens within a 1m2 grow area will get you good results, having a light with a higher wattage that produces more lumens within the same area will help you achieve even better results. It all comes down to how much you want to grow, what lighting systems you can afford and what you are prepared to spend on electricity bills. The stronger the light, the more it’s going to cost you.

Generally speaking, the higher the wattage of the bulb, the more light it produces. The more light that is produced, the better your plants will grow. An excellent way to measure the amount of light you are getting per square foot is through the use of lumens. Wattage and lumens tend to go hand in hand, but can vary system to system. Even though lumens tend to correlate with wattage, it is the design of the light that can have drastic impacts on the actual amount of lumens emitted.

You will have to take the strain you are growing into account here as well, one large sativa may take up the entire area you would use to grow many smaller indicas. Meaning if you plant to grow a lot of sativas you will need a bigger area and more lights to cover them.

There are three factors to consider when deciding how many lumens you need. These are:

and you know what, it is.
eventually im going to get 3 bulbs all going at 2700, but they last 10000 hours ;P
and ive done 3 plants at a time with no issues.
So ill give you the advice ive been given by experianced CFL growers and not guys who use HID and say CFL wont bud.

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

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And people tend to say 2500+ per foot to veg and 3000 to bud *(3500 for denser) is fine.


And people tend to say 2500+ per foot to veg and 3000 to bud *(3500 for denser) is fine.

How many lumens needed to grow cannabis

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

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

The solution is simple: a 400-watt or 600-watt will serve you and your plants much better. A 400-watt HPS puts out approximately 50,000 lumens. With a 16-square foot footprint in a 4’ x 4’, that’s 3,125 lumens per sq. foot. A 600-watter is roughly 80,000 lumens, giving 5,000 lumens per sq. foot in the same tent.

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]

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.

This 4′ x 8′ grow tent uses two 1,000-watt HPS bulbs, but must air cool the lamps to keep temps down. (Photo by Nico Escondido)

A 1,000-watt bulb produces a staggering amount of heat for a garden, especially a small garden space like a tent. In fact, when you break down photosynthesis even further and analyze the process, we find that photosynthesis has ideal temperatures as well. To be exact, 68°F to 74°F is the “gold zone” when it comes to photosynthesis. At 84°F and above, plant photosynthesis begins to slow down significantly.

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.

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).