LED distance Guide

Wattage and Distance: How Far Should Your LED Grow Lights Be From Your Plants?

• 200 Watts – 12-20 inches during the vegetative phase, 8-16 inches during bloom phase
• 400 Watts – 20-27 inches during the vegetative phase, 13-21 inches during bloom phase
• 600 Watts – 30-38 inches during the vegetative phase, 18-30 inches during bloom phase
• 800 Watts – 32-42 inches during the vegetative phase, 19-34 inches during bloom phase
• 1000 Watts – 36-46 inches during the vegetative phase, 21-36 inches during bloom phase

This is not very accurate, hanging height depends on form factor, optics and the area you want ro cover.

Rocket Soul said:

This is not very accurate, hanging height depends on form factor, optics and the area you want ro cover.

Click to expand...

True but for someone just starting out (noobs) it’s a great starting point.

like telling a new driver where the gas pedal, brake pedal etc is.

how hard to press the gas and brake etc vary by car and come with experience.

I think you are missing what @Rocket Soul is trying to say.
Size of the fixture, and the footprint have more to do with hanging height than wattage

Boatguy said:

I think you are missing what @Rocket Soul is trying to say.
Size of the fixture, and the footprint have more to do with hanging height than wattage

Click to expand...

I do understand exactly.

I’ve checked the LED lighting section and to be honest there is absolutely nothing there.

send me a rollitup.org thread that explains your above points and gives guidance to a noob or someone who wants to switch from MH/HPS to LED...

most don’t have a PAR meter or won’t go out and buy one. Ask someone new what’s their form factor or optics on their LED and you’ll get a deer starring into headlights.

Everything I have read basically says pick a distance usually 24” and see if bleaching starts then adjust. That’s not really good advice.
There’s gotta be something out here that has some general guidelines

The basic guideline is 50w per square foot for hid, 35w per square for led. Obviously a single cob run at 150w would need to be kept farther away than a qb, or strip fixture.

BurntByFire said:

how hard to press the gas and brake etc vary by car and come with experience.

Click to expand...

problem is you try to tell the people how hard to press the gas n brake without knowing their car.

Boatguy said:

The basic guideline is 50w per square foot for hid, 35w per square for led. Obviously a single cob run at 150w would need to be kept farther away than a qb, or strip fixture.

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Yes so for my 5x9 gorilla tent = 45 sqft = 1575watts

so I go out and buy two LED lights with these specs (as an example)

720 watts per light
Medical Plant Light 10 strips, 640W, 3500K add 660nm, plus 2X 40W ( UV +IR) , 47X42X4.5inch,120V, Dimming for single fixture, RJ14 adaptor, total 720W, 2.6 μmol/J.
1872umol/s

***During veg period***

Run at 100% for 48”
Or
60% for 24”
Or
Just run 24” at 100% power

use the UVIR option?
Turn it off

Your advice helps me decide which light to buy but not how to effectively use it or a starting point to work from.

A lot of noobs go for the lower priced LEDs off of Amazon. These distances suggested by Mars Hydro are pretty standard among the other 'top tier lower budget' LED sellers.

Just Be said:

A lot of noobs go for the lower priced LEDs off of Amazon. These distances suggested by Mars Hydro are pretty standard among the other 'top tier lower budget' LED sellers.
View attachment 4654311

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Yeah you see it’s not exact science but a great starting point for reference!

....my light is 1872umol/s

i fear this confuse noobs more then it helps with the wide variety of led lights out there.

BurntByFire said:

I do understand exactly.

I’ve checked the LED lighting section and to be honest there is absolutely nothing there.

send me a rollitup.org thread that explains your above points and gives guidance to a noob or someone who wants to switch from MH/HPS to LED...

Click to expand...

There absolutely is very good info here! This is just a tiny sample.

cobshopgrow said:

i fear this confuse noobs more then it helps with the wide variety of led lights out there.

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On a super strong light with 1872 umol/s rated at 720 watts

best to go 48” full power
Or
50% at 24”

for initial transplant into DWC

thats pretty vague information still, not much help for many.

question should be more like
ppfd (per watt), spread of leds, used area, what should be the distance to the plant?

Much also depends on light design, heat sink or passive, ventilation, etc.......everyone's circumstances are different. AND whether or not you are adding CO2.

Rocket Soul said:

This is not very accurate, hanging height depends on form factor, optics and the area you want ro cover.

Click to expand...

Boatguy said:

I think you are missing what @Rocket Soul is trying to say.
Size of the fixture, and the footprint have more to do with hanging height than wattage

Click to expand...

cobshopgrow said:

thats pretty vague information still, not much help for many.

question should be more like
ppfd (per watt), spread of leds, used area, what should be the distance to the plant?

Click to expand...

hanging height depends on ...ppfd (per watt) ....form factor (Size of the fixture, and the footprint), optics (spread of leds) and the area you want ro cover (used area)... i will add ....and the reflective walls (incluyendo suelo y techo) y temperaturas de la canopia (plant canopy temps) y del used area (temps ambient ...zone ventilation or ... climatization used..,,,,and....)...

por tu like bro C anulo la e function... y edito añadiendo algo mas...

SI Wilson...creo que el bro RS y otros bros le querian decir a el que hay muchas cosas a valorar para poder generalizar...a el por lo que veo le cuesta dar al like...

paz

Saludos

BurntByFire said:

Wattage and Distance: How Far Should Your LED Grow Lights Be From Your Plants?

• 200 Watts – 12-20 inches during the vegetative phase, 8-16 inches during bloom phase
• 400 Watts – 20-27 inches during the vegetative phase, 13-21 inches during bloom phase
• 600 Watts – 30-38 inches during the vegetative phase, 18-30 inches during bloom phase
• 800 Watts – 32-42 inches during the vegetative phase, 19-34 inches during bloom phase
• 1000 Watts – 36-46 inches during the vegetative phase, 21-36 inches during bloom phase

Click to expand...

Is this the actually wattage the led uses or the hps lighting equivilant??

Meast21 said:

Is this the actually wattage the led uses or the hps lighting equivilant??

Click to expand...

It's not really usefull info. 600w from a light where the total area that emits light is 3x2 feet ( for example) can be hung much closer than a cob light of 600w which has an emitting area of a few square inches.

In the same sense: does 2 x600w HPS need to be hung at the same distance as one 1200de HPS? No, cause they spread the light in a different way. Check the links above and mfer recommendations or link your light for help.
By the way in 99.999% cases of modern posting here it's actual power draw, non of this equivalency bogus, or potenial max output of diodes. Just wall draw.