cost of running 1000w led grow lights

[Chris in Hamilton]

I think if the bulbs were hot enough it would. By the time I moved the plant to the other side of the fixture the spike was even with the hood. When it bloomed it was a few inches higher. With the number of other fixtures in the room there is a lot of reflected light so I guess it was ahppy with that.

[Regelian]

Suddenly lots of response to the subject! Hmm. Well, it is a bit limiting to say red and blue, as the spectrum is fluid. What we do know is that chlorophyll requires light from the blue end (high energy, small wavelengths) and the red end (low energy, longer wavelengths). This is all relative, as we are talking about the elctromagnetic spectrum which ranges from gamma to infrared to radio-waves. The PAR part of the spectrum is light visible to humans. This relates to our view of the world. Many animals see beyond these wavelengths (380nm to about 700nm is human vision), with birds seeing well into the untraviotet, as well as insects, fish, crustations, and so on. Over about 750nm we call is simply heat!

In the attached diagram you can see that the green to orange range is pretty much inactive for photosynthesis. Land plants have chlorophyll a and b. Carotenoids vary from plant to plant. Now, in order to enjoy the myriad colours of our plants we require the entire spectrum in the lighting source, remember, human vision is based on red-green-blue sensitivity and our brains do the rest.

Another factor to consider is the light output of specific LEDs. Blues produce much more light energy than red consuming the same current. Most arrays for plants are 60% red to only 40% blue to compensate for this. Also, red light triggers the blooming sequence in most plants and needs to be properly administered to steer the blooming (think of seasonal pot plants).

As the aesthetic is, for myself, a deciding factor, lamps I've designed contain white LEDs to compensate for the otherwise missing spectrum.

I hope this is not getting to complicated.

[Dorsetman]

The attractive thing about LED lights when they first appeared were the very low wattage, and hence low running cost. But the ones I tried, including a 275 watt job whichI had almost touching the leaves failed in one important respect - the growth rate was poor. Then I read , somewhere on one of our forums, that the best LEDs achieve 4 lumens per watt, whereas my 600 watt metal ballast "twin spectrum" lamps are way, way beyond that ( and are the basis of the results I am showing with my cattleyas) and moreover cover a much wider area of bench too. I tried half a dozen different LED jobs, and they all ended up at the local recycling facility aka rubbish tip .

[Regelian]

Actually, the efficience of LEDs is well over twice that of the best halides. However, lumens are for humans, not for plants. Lumens are a measurement of the visible light spectrum. Plants use relatively little of this spectrum, which is why an efficient plant LED may produce less visible light than a halide, In other words, the halide is producing mainly non-usefull light for photosynthesis. Plus an amazing amount of heat, which is a further waste of energy. Interestingly, this extra heat may be very beneficial to plants, as we often grow them too cold in the Winter due to our house heating.

There are many cheap and ineffective LED units on the market for this very reason: the customer doesn't understand what he/she is buying. We cannot use the previous parameters to choose an appropriate LED, as they simply are not the same kind of light-producing mechanism. LEDs are very wavelength specific, previous commercial light sources are/were not. The technology did not allow for this, thus they were marketed in a way that made them attractive for the buyer. Not to take away from what they CAN do, but one needs to understand what their qualities are and how this may be applicable to any specific usage.

For photosynthesis we require deep red and deep blue light. All the rest of the spectrum is a waste of energy. Devices developed to measure light of previous light sources (typical light meter) are heavily weighted to the yellow spectrum. They barely register the red or blue spectrum, thus will always give a false reading for 'grow' lights. Of course, the adverts do not mention this, as we do believe what our eyes see. The reference you want is PAR (photsynthetic-active-radiation) and specifically with high output responses at 450nm (deep blue) and 660nm (deep red). Ignore Lumens/Lux, they mean absolutely nothing for LEDs.

When choosing an LED lamp one needs to know the consumption (Wattage) and the drive level (Amps x Volts). A top quality LED, ------ runs with a low amperage (.25-.5 A) at a voltage that brings 2.4 to 3 Watts. If you've forgotten, Watts= Volts x Amps. Therefore, i.E., 3W = 6V x .5A. This drive level may be varied by the lamp builder and often is to get an apparent better efficiency. I say apparent, as the higher you drive an LED, the less efficient it becomes and the shorter its lifespan. In theory, and there are lamps doing just this, you can run them a 1 Ampere with 5 Volts, giving 5W comsumption, but you have halved the lifspan and reduced the efficiency by about 30%. This is the fine print we do not/cannot read and which leads to disappointment.

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Hope this helps..

Jamie

[raybark]

Metal halide lamps put out about 125 lumens per watt, and HPS is about 140. CFLs typically run about 75 (losing some to the inside of the spiral), while T5 fluorescents are more like 100.

LEDs can be 100 lumens per watt, or more, and I am having good success growing my remaining plants under them.

[Regelian]

Ray, the 'white' LEDs I've been using are around 160 LW. There are more efficinet ones on the market, as my lamps are between 4-10 years old. Been doing this for a while. Again, the PAR spectrum is what one needs to consider, not the white light mixture, per se.

Jamie

[sciencegal]

It can come down to how well your plants do under what you've got. I bought a relatively cheap LED shop light. The box says it is 40 watts, 4500 lumens. My tall latouria dens are under it. The leaves on one of them that were too close to the light turned purple so I moved it away a bit. They all seem to be doing well, producing buds and reblooming. I have my large Ansellia africana sitting on the floor with an LED light bulb (not sure without looking what watts but it was as high as could find) in a reflector about 3 feet above it. It also get some indirect light from the windows. That has been the set-up all winter. It produced two many-branched spikes which are now blooming. I have the same bulb in a reflector over a pelargonium that spends the winter indoors. It has been in constant bloom all winter under that light.

[raybark]

Jamie, the ones I am using are rated above 100L/W as well. Some are Philips Greenpower production units, white with deep red, and some small, custom-made lamps I used to sell, that are white with added red diodes.

If you do enough reading, it seems apparent that the level of photosynthetic photon flux (PPF) is probably more important than the actual spectrum, within reason. I used to have a "seedling incubator" outfitted with Philips Red/Blue production units, then switched them out to the White/Deep Red - same wattage and PPF - and the plants just kept on just fine. You certainly wouldn't want to use just red or just blue, as that will have some effect on the plant morphology.

I have seen some Cree outdoor floodlights at a "big box store" that are bright as hell, and I'd bet they'd be just fine as plant lights.

[Regelian]

Ray,
yea, the whites are based on the royal blue with a phosphor, which gives lots of blue light in the spectrum, but literally no red. Your red supplement is right on. I wouldn't worry about morphology with red/blue, rather the fact that it is pott-ugly to the human eye! We really need the green-yellow to balance the spectrum in our brains.

All this said, I try to use the sun as much as possible, but it is nice to have an alternative or supplement.

Jamie

[raybark]

In my custom-made lamps, I had the factory use cold white and warm white chips, and while both phosphors did fluoresce some red, I wanted to add more.

There is nothing that says that the right phosphor cannot put out the right spectrum - it's done with fluorescent plants lights. It's just that the market hasn't evolved to that just yet, and it's easy to just different colored chips.