square footage VS cubic feet?

[rick3066]

ok I can figure sg. footage easy enough.. but my minds eye sees cubic feet when evaluating an area.
anyone care to clear up my fog?

 

[Hosebomber]

Re: square footage VS cubic feet?..

What exactly is the question here? Square footage is a 2D calculation of area length times width. Cubic feet is the 3D calculation length x width x height.

 

[rick3066]

Re: square footage VS cubic feet?..

perhaps its...why do we calculate sg ft ..doesnt a plant grow in 3d? if using inches..lenghth x width / 144...my little 4 ft high plant is getting 205 watts of cfl...trying to see if that is ok ? she looks good...but hey thanks bomber

 

[WhatDoYouDo]

Re: square footage VS cubic feet?..

They use square footage because the leaves on the top layer absorb/block most of the light and the ones below see little of anything. If your light is above the plant, it will hit the top leaves first and stop, so square footage is the most useful way to describe lighting coverage.

Do not get confused tho, they use square footage but they also tell you to hang the light a certain distance above the plant. That means you are actually working in cubic feet.

The reason they dont use cubic feet is because the height needs to be a fixed distance. for example, if the company says an LED light will do an area of 2'x3' at 18 inches, that is 6 sq ft, you ignore the 18 inches because if you used it and did cubic feet, it would be 9 cubic foot. 9 cubic foot could mean anything, that could be 1ft by 1ft area with a light hung 9ft high, which would never work.

Basically, Square footage is the best way to rate lights on the amount of coverage they can do. When you start to talk about cubic feet, you are using a number with worthless value. It may be useful for some applications in growing but for 90% of them, you really dont need it.

Cubic feet is more useful when talking about the volume of air/co2 in the room and less about the light.

 

[Khraevyn]

Re: square footage VS cubic feet?..

They use square footage because the leaves on the top layer absorb/block most of the light and the ones below see little of anything. If your light is above the plant, it will hit the top leaves first and stop, so square footage is the most useful way to describe lighting coverage.

Do not get confused tho, they use square footage but they also tell you to hang the light a certain distance above the plant. That means you are actually working in cubic feet.

The reason they dont use cubic feet is because the height needs to be a fixed distance. for example, if the company says an LED light will do an area of 2'x3' at 18 inches, that is 6 sq ft, you ignore the 18 inches because if you used it and did cubic feet, it would be 9 cubic foot. 9 cubic foot could mean anything, that could be 1ft by 1ft area with a light hung 9ft high, which would never work.

Basically, Square footage is the best way to rate lights on the amount of coverage they can do. When you start to talk about cubic feet, you are using a number with worthless value. It may be useful for some applications in growing but for 90% of them, you really dont need it.

Cubic feet is more useful when talking about the volume of air/co2 in the room and less about the light.

Thank you!! I was wondering this same thing myself and u answered it perfectly!!!