LED Light distances

[Kneeko]

Led Light distances



How do you judge ?

1. Manufacturers suggestions
2. Burn and then back off

Or is there a way to determine the max absorbable intensity before it becomes counter-productively too intense and just wastes electricity ?

Also how wide is that zone between burn and could use more light ?

 

[One Drop]

36” above seedlings 24” above vegging plants 18” above flowering plants simple as mate

 

[R3za92]

Personally? Take a guess based on the manufactures specs and see how the plants react

The correct way? Decent Quantum par meter/quantum sensor like an apogee mq-500 and adjust to 1000ppfd average across the canopy. But fuck dropping $500+ until I’m running a warehouse

 

[puggle6]

I'm off to measure mine

*edit,

Righto, it's 500 LEDs @ 26 seppos from germ

 

[afghan bob]

They reckon 6in is the average mate

 

[Indy]

Only a noob with this LED stuff, but i'm using the Photone app (Apple, Android). Do a bit of research for recommended values for different stages of growth, and adjust to what feels right to you. I'm about 3 weeks from wrapping things up and i'm running about 900 PPFD in the middle which has it at about 650PPFD in the corners, the light is a bit over a foot (35cm) above the canopy.

But after reading a bit lately, it seems Day Light Integral (DLI) might be a better suited practice. But dunno for sure (noob status). Just some stuff i've been getting my head around lately as well..

Good luck with it, Kneeko.

 

[veritas629]

Indy is on to it. I use 100-300PPFD for seedlings, 500-700 veg, and 700-900 flower. Some strains need more, some less, so watch how the plants behave. Much more than 900PPFD and you're starting to waste electricity unless you're using CO2 supplementation. I use a Spot On PAR sensor. Yeah it cost a bit, but I found out I was able to turn my lights down a bit. I bet I saved enough electricity money to cover the PAR sensor on my first grow using it.

 

[Kneeko]

Ok... So If my SE3000 Spider farmer 300w LED is technically putting out 900ppfd at 12” for flowering... why would a 600w HPS give better results..?

Yes the intensity is greater but

Isn’t there a point of diminished returns ?

 

[R3za92]

Ok... So If my SE3000 Spider farmer 300w LED is technically putting out 900ppfd at 12” for flowering... why would a 600w HPS give better results..?

Yes the intensity is greater but

Isn’t there a point of diminished returns ?

Leaf temps probably. The hps has ir which raises leaf temps causing transpiration and Also means humidity control is less of an issue

 

[veritas629]

Ok... So If my SE3000 Spider farmer 300w LED is technically putting out 900ppfd at 12” for flowering... why would a 600w HPS give better results..?

Yes the intensity is greater but

Isn’t there a point of diminished returns ?

This is exactly my understanding of the situation. More than about 900ppfd and you need CO2 supplementation to reap the benefits of even more light.

I also suspect that R3za92 is right about the IR, higher leaf surface temps, and more transpiration. However, I think, without any hard evidence, that more transpiration would make humidity control a bit harder. More transpiration = higher humidity = more circulation and/or dehumidification required to avoid mold etc. And you also need to consider the VPD aspect too.

My personal experience of only two grows with a PAR sensor is that above 1000ppfd and my plants looked light stressed. Your results may vary...

 

[R3za92]

This is exactly my understanding of the situation. More than about 900ppfd and you need CO2 supplementation to reap the benefits of even more light.

I also suspect that R3za92 is right about the IR, higher leaf surface temps, and more transpiration. However, I think, without any hard evidence, that more transpiration would make humidity control a bit harder. More transpiration = higher humidity = more circulation and/or dehumidification required to avoid mold etc. And you also need to consider the VPD aspect too.

My personal experience of only two grows with a PAR sensor is that above 1000ppfd and my plants looked light stressed. Your results may vary...

The ir stimulates transpiration by raising leaf temps above ambient. This also effects humidity around the leaf surface. Also higher temps lead to a wider range of humidity that plants can transpire at

 

[Kneeko]

I want to try HPS... cus Ive only used the SF3000 LED.
Would 600 be overkill in a 1m x 1m tent
Or should I go 400 ?

Humidity is not an issue cus I have a kickass dehum...

 

[Madmick]

600 should do the trick , fits with that size nicely

 

[elsooto]

Up to you kneeko, you could always get a 600 that has the setting to run at 400 if 600 became an issue.I use a 400 in the same size tent and it does the job. I normally only run 1 plant at a time tho so it's a decent veg period. Think my pb was 14.5 oz off the 1 plant, and could better that I reckon

 

[Indy]

Yep, like soot mentioned, a variable setting digital ballast would be a good fit..

Lumatek 600W digital ballast

That way you got the option of 250w, 400w, 600w and 660w light. A straight 600w in a 1m x 1m space might be a bit much in the heat dept, if you don't have a cooltube extracting shitloads of air.

 

[Indy]

Here's a cheaper option, but I can't say I've heard of the brand before. The old buyer beware deal.
These threads shit me. They usually send me down the path of another shopping spree.

 

[elsooto]

Here's a cheaper option, but I can't say I've heard of the brand before. The old buyer beware deal.
These threads shit me. They usually send me down the path of another shopping spree.

@Gazza might be able to give some feedback on this one. Pretty sure he's used one

 

[Kneeko]

Im liking the looks of the Lumatek gear... Trying a cheap $200 HPS setup has grown to over $500 now..
Thats the problem when ya get bitten and start shoppin....

 

[Indy]

If you're looking at getting a reflector as well, you may want to consider whether you want to have the bulb set up horizontally or vertically. A lot of old school growers prefer the Chinaman hat style reflector (bulb is vertical) because its meant to produce a better spread of light. But there's others like me prefer to hold the bulb horizontally with either a Adjust-a-Wing or cooltube reflector.

Anyway, check out the spec sheet for a Philips 600w HPS Bulb (Photometric Data) and give it some thought yourself if interested.

 

[Gazza]

@Gazza might be able to give some feedback on this one. Pretty sure he's used one

One I got off soots is a digilumen and the other is a havemax

Anything’s better than a mag ballast, at least the digital have a built in 10 amp fuse for piece of mind.