Lumens and marijuana growing

The Cannabis Grow Bible

by Greg Green

marijuana lighting

Now for the big question. How many Lumens do I need? Well this depends on three things. (1) How much do you want to spend? (2) How many plants do you have? (3) How big is your grow area.

You do not want to go less than 2500 Lumens, even for one plant. You want to get the best so you need to hit the 45000 mark or more. In general one light that casts 45000 lumens is enough to cover a workspace of about 3 feet by 3 feet. This is quite an average space and you will probably get anything between 6 – 9 plants in that area. Again we must keep in mind the strain that we are growing. One large sativa plant can cover a 9 square foot grow area in no time. Short indica plants are different. You can get maybe 12 plants into a 9 square foot grow area. If you really want to pump up your plants then you may consider a lamp that casts 100,000 Lumens or more. If you want a bigger grow area then you may consider 2 lamps that cast 100,000 Lumens each. All is relative to how much you want to grow and the size of your grow room.

Letmarijuana lights’s say for the record that we would like to grow 4 plants. Then what we should aim for is a light that casts 45000 Lumens. This means we should buy a 600-Watt HID system. Let’s say we want to pump up our available light to around 60,000 Lumens. This means we should buy a 1000-Watt HID system. If our area is bigger we might need 2 or more 1000-watt HID lights to achieve this. It all very respective to the 3 elements we mentioned above.

There is nothing wrong if you want to use a 1000-watt HID light on 2 plants. They will grow bigger and better. The only thing is, do we really want to spend all that money on the light and the electricity bill? HID lights range anywhere between $220/£200 and $700/£670 for a full kit. You may be able to buy the parts and build your own, but this is only recommended if you have some experience with lights first. A 600W HPS kit should cost about $250/£230. This is money well spent if you want great plants with big buds.

Over time you will understand more about grow rooms and how to light them properly. With experience you should be able to tell what light suits your needs. As a general rule, when in doubt buy a 400W HPS or better.

Cannabis Grow Bible

1 comment to Lumens and marijuana growing

  • Jim

    Great article! I have a question, can you tell me if I have 230 plants, how many square feet of a room will I need to support a good grow and veg room? And what sort of lights will work best? I want to experiment with some LED lights too, if possible?

    If you could be of any assistance that would be terrific!

    Thank you,


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