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lumens for growing weed

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

now before all you HID junkies come at me,

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

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veg phase: 12 hours on 5.5 off, 1 on 5.5 off (that’s 24 hours). this cycle will not harm your plants and will perform better and reduce about 40% of your energy consumption and you will not have the issues that 24/24 gives you.

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.

I have a space about 1 food deep by 2feet wide.


CFL will bud your weed fine at 3000 lumers per each food squared of area.
During budding keep them 3" near plant tops and they will penetrate fine.

CFL can bud weed and grow it at a good pace just fine. IF you have the right spectrum.
Dont try buddin in blue (6500k)
wont happen.

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.

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.

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

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.

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.

400W and 600W light bulbs are the favorite of indoor cannabis growers. Some growers even use light bulbs with 1000W. This is logical, when you consider ‘more light = bigger yield’. But watch out; the more Watts you use in your grow room, the hotter it gets. Especially with 600W and 1000W light bulbs the temperature can become way too high for your cannabis plants in your grow room. So be prepared to do some temperature control when using strong light bulbs.

Lumens for growing weed

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.

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.

Most plant leaves do their best conversion with sunlight between 3,000 and 4,000 lumens per square foot. Let’s assume, on average, that a 1,000-watt high-pressure sodium (HPS) bulb has an output of 100,000 lumens. At a leaf’s peak efficiency of 4,000 lumens per square foot, that leaves an optimal coverage area of 25 square feet—or a 5’ x 5’ footprint—for a 1,000-watt bulb.

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]

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.

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.

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!

However, rather than go too deep into PAR, I will answer your question in the more basic form, as lumens do have a place in this discussion, since you specifically ask about lighting a specific size of space. Using a 4’ x 4’ grow tent as the example of the space we want to light, we must first understand how much light is optimal for plant growth and development. To do this, we examine the process of photosynthesis, where light energy (photons) is converted to plant energy (glucose or sugar).