Jonus
Well-Known Member
Absolutely. I wouldn't waste your time on those light rails. My LED light currently has 1904 5mm LEDs on it, at 112 watts, and it does not measure up to a 400 HPS. Not because there isnt an abundance of light of the blue and red spectrums that plants eat, its about the way LEDs emit light and its about lumens per square foot.
Because LED lights are directional, the whole mylar/vizscren plastic idea for bouncing light to the lower branches is pretty much annulled by the directional light.
You end up with a lack of light onto the lower fan leaves, causing growth to slow underneath. If you let the plant get over 12 inches it then begins to stretch and become top heavy.
So as a vegging light say up to a foot, LEDs are fine.
The next issue is lumens per square foot. Almost none of the LED suppliers will go into this detail. Most because they do not understand the amount of light intensity plants need to speed grow, and perhaps some of them do, so they leave it out for more sinister reasons.
As I understand it, plants will veg at a fairly fast pace if you are providing them with more than 2500 lumens per square foot at the top leaves. I tested my LED setup with a light meter which says its outputting around 4000 lumens per square foot of light. It does that consistantly from about 2 inches from the LEDs to about 12 inches below the LEDs. After that it diminishes rapidly.
So my results in the grow area match the math, there is plenty of light for vegging and I can veg up a foot of bushy tight noded growth in about 2 and a half weeks from clones. I place my lamp about 2-3 inches above the top leaves and light will penetrate down to the bottom branches on anything 12 inches in depth below.
However it takes more than 10000 lumens per square foot of correct spectrum light at the top of the plants to successfully grow 'big bud'. So LEDs have a ways to go yet before being able to emulate an HPS.
The other issue with the directional light emitted from LEDs, is that you need a lot of coverage of LEDs. i.e. a 400 mH and shade can easily 'veg' (not bud) an area of 4 foot square. With LEDs if you really wanted to match the metal halide, you would need a 3 foot square of LED lights to match.
My current lamp is 60cm x 40cm and the light from that covers about 3 foot x 2 foot of grow area at just over a foot from the top of the pots (pots are about a foot high, so 2 feet from the floor). When I say 'covers', I mean, covers it as good as a metal halide would for vegging.
1:3 ratio is fine if all you are doing is vegging. But the thing with LEDs is that a 600 watt LED lamp is huge. Its just the same thing as I have but more of them. The overall lumens per foot output is no different so it still wont bud like an HPS or CFLs will. It will however veg a large area since the area of those 600 watt LED lamps being advertised is substantial.
Ive just purchased another couple of thousand LEDs and am making up a new light. Unlike my current light which has the 4000mcd (megacandela) blue LEDs and 8000mcd red, these are 10000 and 20000mcd LEDs. The new light will have around 3800 LEDs and covering twice the area as my current light.
So I am keen to get it finished and tested under the light meter.
Because LED lights are directional, the whole mylar/vizscren plastic idea for bouncing light to the lower branches is pretty much annulled by the directional light.
You end up with a lack of light onto the lower fan leaves, causing growth to slow underneath. If you let the plant get over 12 inches it then begins to stretch and become top heavy.
So as a vegging light say up to a foot, LEDs are fine.
The next issue is lumens per square foot. Almost none of the LED suppliers will go into this detail. Most because they do not understand the amount of light intensity plants need to speed grow, and perhaps some of them do, so they leave it out for more sinister reasons.
As I understand it, plants will veg at a fairly fast pace if you are providing them with more than 2500 lumens per square foot at the top leaves. I tested my LED setup with a light meter which says its outputting around 4000 lumens per square foot of light. It does that consistantly from about 2 inches from the LEDs to about 12 inches below the LEDs. After that it diminishes rapidly.
So my results in the grow area match the math, there is plenty of light for vegging and I can veg up a foot of bushy tight noded growth in about 2 and a half weeks from clones. I place my lamp about 2-3 inches above the top leaves and light will penetrate down to the bottom branches on anything 12 inches in depth below.
However it takes more than 10000 lumens per square foot of correct spectrum light at the top of the plants to successfully grow 'big bud'. So LEDs have a ways to go yet before being able to emulate an HPS.
The other issue with the directional light emitted from LEDs, is that you need a lot of coverage of LEDs. i.e. a 400 mH and shade can easily 'veg' (not bud) an area of 4 foot square. With LEDs if you really wanted to match the metal halide, you would need a 3 foot square of LED lights to match.
My current lamp is 60cm x 40cm and the light from that covers about 3 foot x 2 foot of grow area at just over a foot from the top of the pots (pots are about a foot high, so 2 feet from the floor). When I say 'covers', I mean, covers it as good as a metal halide would for vegging.
heh yeah you see a lot of that, even much more inflated than that. Some even claim the 90 watt UFO matches a 600 HPS...600 watts would be equivilant to aprox. 1500 watts according to ppl who sell the products
1:3 ratio is fine if all you are doing is vegging. But the thing with LEDs is that a 600 watt LED lamp is huge. Its just the same thing as I have but more of them. The overall lumens per foot output is no different so it still wont bud like an HPS or CFLs will. It will however veg a large area since the area of those 600 watt LED lamps being advertised is substantial.
Ive just purchased another couple of thousand LEDs and am making up a new light. Unlike my current light which has the 4000mcd (megacandela) blue LEDs and 8000mcd red, these are 10000 and 20000mcd LEDs. The new light will have around 3800 LEDs and covering twice the area as my current light.
So I am keen to get it finished and tested under the light meter.