EDIT:
I split this discussion off from another thread so we don't hijack with a debate over how much light we need to grow top shelf mj...


oh i dont know,,my cheese came out pretty good especially as she was only 13 inches high at the end, bless her (vegged her for three weeks under a mates 250W HPS cos i ran out of room lol then moved her in under my 300W LED)



BudShots

Pretty good compared to what?



Let's not highjack her thread. If you want; we can start a new thread where we can discuss the effects of not enough light vs high end results.

lol bloody hell, now thats what you call a bud, ok, new thread with my mates 4 plasma 600 grows then lol

Fine, I'll move these last few posts to the new thread after...

One of the biggest and worst myths regarding LED lights is that you can replace much bigger HID lights with a small LED light and results just don't back that up.

With HID you want at least 50w/sqft for top shelf results and even more is usually better. There are ridiculous claims that LED can keep up with much less w/sqft and those claims are never backed up with any objective proof. One person tried to claim that 2-5w/sqft was enough and others have claimed 15-30w/sqft can compete with high end HID grows.

I call bullshit...

When you skimp on light you hurt your yield no matter what kind of lighting you use. I'm not just talking about grams although that can be less too, I'm talking about size and density too. Above, Deadlock posted some nice pictures of a decent auto grow but that doesn't tell the whole story.

Below are a few more pictures that I dug up from a yahoo image search that show the differences in not enough light vs a lot of light.

Popcorn buds that didn't get enough light:



Better:




Unfortunately, even with higher w/sqft numbers LED lights cannot keep up with 1000w HPS grows as another journal showed:
beefxer-s-mmj-grow-test-solarstorm-400w-t215.html
(Yield comparison pics on page 5, then he goes onto another grow)

Now, before anybody has a coronary, I'm not saying that LED lights can't flower good buds, we've seen journals where they have. I'm saying that you can't skimp on lighting, despite unbelievable marketing claims, if you want top shelf results. Can you flower with less w/sqft? Yes. You'll still get some kind of result but if you want to maximize the genetics potential you can't skimp on lighting. Period.

Yup i totally agree.
When your talking about MJ,
Hit the nail on the head, you cant skip on light,

LED's for me are the ideal solution to 'keepin a low profile when growing' tho and i think thats what theyre best for
All this comparison to HPS is, rubbish, i agree.

You cant beat the sun and hps/plasma are the closest thing to it.

I also believe that plants rely a hell of a lot on IR, now, you cant have a lot of IR in normal LED growlights, maybe 1 LED, but not at a high
enough spectrum as the heat IR generates at higher NM will cook ya LED's wires. lol

I know that the sun does pump out a lot of IR, UV and loads of other spectrums so to get a LED to match that is gonna be a challenge.

For growers that have the space and can afford the running costs by cash cropping etc... then hps all the way

For people that grow for themselves, LEDs may be expensive and comparison argument causing but they do the job, silently and discreetly.
But main point is, filling up a the same area with HPS Versus same area with LED, HPS will win, hands down

But LED's are getting there and they wont terraform MARS with HPS let alone put them on on the ISS or the CNSA's (Chinas) space station.
Just a bit hot and dangerous, but hey thats another thread innit?
Hat off to the size of those buds aswell! monster buds...

I take it all of that is for medical use? Wished i lived in california, would love to involve my medical experience with this 'miracle' plant.
Our poor MS sufferers go on suffering....stupid politics. Hence LED, quietly does it....lol

The key to keeping a low profile has nothing to due with LED nor HPS, imho. They make low wattage HPS and very high wattage LED lights with a lot of heat and loud fans. The key to keeping a low profile is very good security regardless of what kind of light people choose.

Mother Nature is often a limiting factor. You *can* beat the Sun, except when it comes to price. Plasma lights have potential but I'm not switching to plasma yet.

There is a theory, that we've talked about on the forums, that suggests that the IR spectrum may be why LED lights lack the yield that HID lights can produce. Some have suggested that raising the ambient temps may help LED lights yield better since most of the LED lights lack the IR spectrum.

Noise is certainly one of the security factors that I was talking about. HID cooling doesn't have to be excessively loud and not all noise draws suspicion.

LED lights are better for some crops than others, obviously. I doubt that they're growing mj in space...yet. LED lights may very well take the crown, in the future, but not today.

We were using it as medicine long before it was legalized for medical reasons in California, patients shouldn't let a law keep them from relief. It's still illegal on the federal level here.


The point still stands; you can't expect top-shelf results by skimping on light and not enough w/sqft is skimping. Suggesting that small light (300w) will properly cover a large space (4x4) is skimping (18.75w/sqft) and not based on real world grow results. CLW suggests 40w/sqft for flowering with their 5w diode LED lights and I'd suggest that even that is exaggerating a bit if you want top-shelf results. You'll certainly do better with 40 than 20 or 30 but even with higher numbers HPS is still king...for now. I've yet to see any LED grow that beats top HID grows.

I'd love to be proven wrong though...

Given top American assembled LED: W/ft^2

I've heard 40-50W/ft^2 for HID, but am having trouble getting an answer to a good starting point for optimal power-drawn LED W/ft^2. Let's assume a thin canopy (SCROG) so that penetration issues can be removed from the equation for the moment. I'd like to focus on PAR accuracy and think later about the virtues of blasting one's canopy with a white Cree baseball.

Opinions?

CLW suggests 40w/sqft for flowering with their lights and that's the most honest manufacturer I've seen. We've had LED journals that exceeded that but there isn't a single "right" number. I'd say 40w/sqft is a good "starting number" (I'd want more) but I've often said that PAR is just a marketing measurement so I wouldn't depend on that number having actual "real life" meaning when using it to compare different types of lighting.

SME,

I actually have an ancient LP of Big Bambu. The enormous rolling paper got lifted at a high school party most unfortunately.

The 40W number - would that be ave. power drawn or max wattage?

Thanks, Low Water