Lighting The argument for a higher light

[Drownomatic]

When temperatures allow it I raise my light as high as possible.

You may have heard me and some of the others mention the inverse square law as it applies to the fall off of light.

'Light radiates at the inverse square of distance'

Lets say your light is a foot away, and you get a DLI reading of 40. From the top of your canopy to the bottom is another foot.

The bottom is twice as far, and will only receive a quarter of that amount, 10 DLI

Now lets look at what happens if the light is raised to 3 ft, and turned up to again give 40 DLI.

The top of the canopy is 3 ft, and the bottom is 4ft away.

The bottom receives 22.5 DLI, more than double!

If the light is raised to 4ft above canopy the bottom DLI goes over 25, and from here the return is minimal.

The downsides to this are much higher temperatures inside the tent, and of course more electrical costs.

You also need a fairly powerful light.

 

[WildBill]

When temperatures allow it I raise my light as high as possible.

You may have heard me and some of the others mention the inverse square law as it applies to the fall off of light.

'Light radiates at the inverse square of distance'

Lets say your light is a foot away, and you get a DLI reading of 40. From the top of your canopy to the bottom is another foot.

The bottom is twice as far, and will only receive a quarter of that amount, 10 DLI

Now lets look at what happens if the light is raised to 3 ft, and turned up to again give 40 DLI.

The top of the canopy is 3 ft, and the bottom is 4ft away.

The bottom receives 22.5 DLI, more than double!

If the light is raised to 4ft above canopy the bottom DLI goes over 25, and from here the return is minimal.

The downsides to this are much higher temperatures inside the tent, and of course more electrical costs.

You also need a fairly powerful light.

And there's more reflected light when it's turned up also.
I don't remember who asked this question yesterday. I was just too stoned to go into more depth and actually explain it properly!


edit...................... was it you @NORBY ?

 

[elcoloan]

Migro has something to say about the inverse square law:

 

[FarmerJake]

Migro has something to say about the inverse square law:

He tested the same intensity at different heights, what OP mentioned was setting canopy intensity at the same DLI from different heights and that penetration would be stronger with high light intensity from further away, than lower light intensity from closer. A lot of variables for stoners to ponder but I would say the best penetrating power is the sun and that’s a super intense light from super far so it makes sense that upping intensity and distance would be better than lower and closer

 

[WildBill]

He tested the same intensity at different heights, what OP mentioned was setting canopy intensity at the same DLI from different heights and that penetration would be stronger with high light intensity from further away, than lower light intensity from closer. A lot of variables for stoners to ponder but I would say the best penetrating power is the sun and that’s a super intense light from super far so it makes sense that upping intensity and distance would be better than lower and closer

The question can be quite moot if you have a large and powerful light in your tent.
I haven't been able to run my HLG DIABLO 650R my at full blast yet. In my first grow I tried running at a lower height and lower wattage, but didn't get the coverage I liked. It wasn't as even coverage as I wanted.

I changed from an 8 inch filter in fan setup to a 6 inch filtering fan so that for the exhaust. I only did that to get the clearance so I could raise the light up even higher. This is a gorilla tent so it's taller anyway. Well I can't put the extension on it though.

With hanging a light high and turning it up, you have more photons available. A lot of that light is reflected light that reaches the canopy. Yeah, the photon does lose energy when it's reflected off a surface, but it's at a different angle and can hit different areas in your canopy.
With hanging that light high, larfy bud has declined quite considerably