I have never grown with LED's, but I am researching them now as I am considering using them in a future project. The reason most people say L.E.D. grows suck is because most L.E.D. grows do not use nearly enough light. For that mattrer most grows in general do not use enough light. L.E.D. lights do not put out very many lumens, though they create a lot more usable light per watt than HID lights. They also create a LOT more usable light than HID lights and generate a lot less heat. LED's also last a lot longer, most growers change their HPS bulbs after 2 or 3 grows but an LED can go for 50,000-80,000 hours and degrade much less over time than an HPS...that is about 10 years.
The light spectrum the plant can use and the light LED lights generate literally blows HID lighting away. Plants use mostly blue spectrum light for veg, and red spectrum light for flowering. If you look at the two light spectrum charts below you can see what I mean.
The chart for the 600HPS bulb shows that a CLEAR majority of the light being given off falls in the green to yellow spectrum, not very much blue at all, and not very much red at all. This means the lamp is giving off a LOT of light the plant can not use.
If you do a search on Ebay for LED lights, then sort by price high to low, you will some 600watt LED lights for anywhere from $1,500-$2,500.
The other chart is one for a $2,500 600 watt LED called the "Illuminator Superpro".
If you decide to go with an LED, make sure it has TRI-BAND technology. This will deliver a light spectrum similar to the one in the chart below, as you can see, almost all of the light is falling in the blue and red spectrum, where the plants use it. This is why LED's appear blue and red, but HPS lights appear orange. This series LED claims that over 95% of the light emitted is usable by the plant.
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" the 600W Pro Series emits the same amount of absorbable light as a (2) 1,000W HID's, and it is this ability to only emit key absorbable light that your plants are able to use that makes it possible to achieve the parity results with an HID at just a fraction of the wattage. Lumens output is not a key factor in determining plant growth, it is the ability of the plants to absorb and tranform the light energy into photosynthesis and which wavelengths are to be used to achieve those key abosrption points. Lumens are a common measure of output that is used to measure the intensity of HID Lighting, but really has no direct bearing on determining plant growth. Remember that over 85% of the light emitted from an HID Light is wasited in the form of non-absorbable light waves as well as heat energy."
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Most of the ads I read for 600 watt LED lights say they put out as much usable light as TWO TO TWO AND A HALF 1,000 watt HPS lights and can cover a 100 square foot area, with 48 square feet getting what they call "core saturation" which can be translated to "enough light to grow good MJ". A 1,000 watt HPS putting out 145000 lumens can cover about 25 square feet with 5,000 lumens per square foot, so I would understand where they get off saying this 600 watt LED covers as much growing space as two 1,000 HPS lights. LED lights also use no ballast, and you can simply hang the entire unit. There is no light to vent, reflector to adjust, etc.
If you have the money to invest, LED's are the lights of the future. If these lights were $700 instead of $1,500-$2,500, many more people would already be using them. In 5-10 years when the mass production costs have lowered the cost to produce the bulbs and the technology has had more time to come along, everyone will be using LED's. That is just what happens with technology as it develops. Plasma TV's 5 years ago were 500% the cost of now.
Anyway, hope this all helps.
