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Old 10-28-2016, 12:06 AM
GpsFrontier GpsFrontier is offline
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Join Date: Mar 2009
Location: Lake Havasu AZ.
Posts: 1,855

Hello Psycrops,

The interior top/bottom/sides/+raft base will also be wrapped in mylar which should hopefully help with maximizing light.
While Warping mylar around the plants will help reflect light, it will also cause air circulation problems. Air circulation is very important not only for plant health, eliminating heat build up, but also for providing CO2 the plants need to grow as well.

The only thing that peaked my interest to the LEDs was being curious if I could get away with using less lumens for my particular situation. Since that particular led could fit the fixture I was looking at, it was the cheapest of the LEDs and the fluorescent was the cheapest of the fluorescent.
First good LED grow lights aren't cheap. The price is coming down, but their still not cheap yet.

Not 100% sure how efficient the brand I'm getting is, as they're from overseas.
Price doesn't guarantee good quality either since many Chinese companies charge high prices for low quality LED's. So you really have to do your research on the company manufacturing the lights in the first place. Don't trust manufactures propaganda. It's time consuming to do so, but I have seen countless people who were so excited they were going to save so much money in electrical costs, only to find out later after they spent all their money that they weren't really going to save much of anything in reality, and/or the plants were growing malformed.

If using wattage per sq ft, LED-25w per sq ft would put it @ 406.25w required. The LEDs only total to 132w (22w/6 bulbs). Which means I would need 274w/12 more bulbs ($121.92) and around $90 more in light fixture money.
When planing to use LED's you really have to do your own testing. Like I said LED's aren't all created equal, and good ones aren't cheap. With cheap quality LED grow lights ones flooding market, you have to really research the manufacture, and even then do your own testing. The 25 watt to 35 watt per Sq foot recommendation isn't an absolute because it's going to depend on the quality of the LED's themselves. When I say Quality, I mean how they were designed and manufacture. It doesn't mater how many watts a light is putting out if it's not putting out enough PAR light (wavelengths plants use).

Here is a video that tested florescent lights with common LED grow lights.
Low Watt LEDs vs T5 Grow Lights: Seed Starting / Lettuce Test

While looking up the video to post for you, I found this new one he has put out as well.
T5 Fluorescent vs Transcend LED Grow Lights -Hydroponic Lettuce Test

He had good results using those LED's, so I ran the numbers, here's how it breaks down.

T5 florescent
4 foot twin bulb florescent light fixture with bulbs $40
$40x2= $80
216 total watts

T5 LED's
4 foot twin bulb florescent light fixture with bulbs $40 (you don't need the bulbs because you will be using the LED tubes instead, but they come with the fixture)
$40x2= $80
LED T5 bulbs $70 each
$70x4= $280
120 total watts

That's a $280 equipment cost difference.

Electrical costs calculated using the national average of 10 cents per kilowatt hr

Florescent 216 watts running 18 hours a day
Daily $0.39
Monthly $11.70

T5 LED 120 watts running 18 hours a day
Daily $0.22
Monthly $6.60
That's a $5.10 difference in electrical cost per month

$280 divided by $5.10= 54.9. So it will take 54.9 months to break even in electrical costs from the higher equipment costs. 54 months is 4.5 years. It will take nearly 5 years just to break even before you can actually start saving any money.

Even if you are willing to wait 4.5 years before you start saving any money, I find it ironic that the company has a 5 year warranty which tells me that's probably about the lifespan of the bulbs themselves. So just when you are about to start saving money, you will probably have to buy new bulbs and wait another 4.5 years to break even again. If the bulbs wear out before the 5 years, they wont replace them with new bulbs, they will just prorate them and you wont get hardly any money back or towards new bulbs anyway.

The only thing it seems LED has over fluorescent is lumens per wattage and bulb life (quality control issues don't factor in), which my above options put it to around 104 lumen per watt for the LED and 95 lumen per watt for the fluorescent.
Again you cant really compare lumens from one type of bulb to another type of bulb. Florescent lights and LED lights are two very different bulbs. You can compare lumens from one florescent bulb to another florescent bulb, or compare lumens from one HID bulb to another HID bulb. But not a florescent bulb to a HID bulb or to a LED light. I don't think you can really compare lumens from one LED light to another LED light since LED's are so vastly different.

For my particular setup size. I couldn't get away w/ using a MH in my setup as I only will have 20-25"T of room per raft. I should had mentioned this earlier, but the rafts stack on top of each other. The whole setup will be around 59"L x 48"W x 80-90"T and will house 3 rafts.

MH is the best bet, but I wish they made longer bulbs as I have some ground to cover. Plus they're only around $8 which is absolutely nuts.
I'm not sure if your planning to grow them on a shelving system, or side by side with the lettuce raised higher to be the same height as the kale. If your growing them on a shelving system I would go with using florescent lighting. But you don't need long MH bulbs/tubes to be able to use HID lighting. That's why I gave you the example of comparing lower wattage MH lights. You can get the same effect as using long tubes when you use lower wattage MH bulbs spaced out, and without using any more electricity. A typical 400 watt HID light will normally be able to cover a 8-10 foot wide space (80-100 Sq feet) depending on the plants and shading. I attached a drawing showing what I mean. If I read your figures correctly you plan to have 3 systems each just under 20 Sq feet, for a total of about 60-70 Sq feet give or take depending on how far apart each system is spaced, which should easily fit within the sq footage of the example in the drawing I made. 100 watt HID lights aren't easy to find, you really have to look around and make some calls to find them. But they do make them and here is a link to one I found. Mini Sunburst MH w/Lamp, 100W
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