View Full Version : LED Growlights… experience, anyone?
JuniPerez
10-30-2011, 01:32 PM
Hello all! :)
I am considering getting some LED growlights. I know a few years ago they hadn't advanced enough to be a benefit over bulbs in both price and strength. Now I see many people are putting them to use and prices aren't as bad as they used to be.
Does anyone here have experience with these with nanners?? Pros? Cons? Any advise would be greatly appreciated. The only available space in my apartment is my bathroom; about an 8'x10' area and it's not bright enough in there, so lights have to be added.
The last couple of winthers, I have used a 50 watt UFO (blue and red LED's) in my basement, where I have bananas, palms, agave, yucca, bamboo, chili, tomato and many more species, are they are just growing great with the LED grow lamp. It don't use much power and don't generate heat. I use the LED 14 hours every day.
I have just ordered a new grow lamp:
ProPlant6 - Hi. Power PlanteVækst diodepære 17W - 120° - Plante/Akvarie Lys - ProPlant6 - Hi. Power PlanteVækst diodepære 17W - 120° (http://www.prolys.dk/proplant6-hi-power-plantev-kst-diodep-re-12w.html)
More powerfull, and use less power.
Brian
JuniPerez
10-30-2011, 04:03 PM
Thanks... I'll look into that... gotta find a US site...
raygrogan
10-30-2011, 05:20 PM
I've had good luck with the el cheapo CFL's, just get a clamp lamp of some sort. Light weight, no heat to speak of.
fmu65
10-30-2011, 07:13 PM
I got a fluorescent on discount at the local grow shop, but I also use a fluorescent fixture with "deluxe" daylight bulbs that puts off little to no heat and was really cheap. They come in a variety of sizes, even some with reflectors. Cheaper than led and my plants seem happy.
Richard
10-30-2011, 08:20 PM
Here is the scoop on lighting.
Lumens are a measurement of luminous flux – the amount of light perceived by the human eye. Since light bulbs were originally manufactured for human vision alone it became the standard of measure for bulbs. It is still very important in architectural design and in civil building codes. Most governments require that the lumen output of a bulb be included on the label.
Watts are a measurement of the rate of energy transfer per second, which in science and engineering we refer to as power. Watts / square meter or Watts per square foot in the context of lighting refers to radiant flux; i.e., the amount of energy being transferred per second to a surface area.
Example. A popular 23 Watt compact-fluorescent bulb states on the label that it has the equivalent output of a 100 Watt incandescent bulb. This means that the compact fluorescent produces the same lumen output as the incandescent. It doesn’t do this by magically creating energy out of nothing! Instead, that particular bulb is more efficient at producing radiation in wavelengths that stimulate the human eye.
Plants absorb light from the human visible spectrum, but (depending on the plant) in ratios of about 1/3 of the blue sub-spectrum, about 1/3 of the red sub-spectrum, and about 1/3 of the rest combined. Chlorophyll – whose central atom is Magnesium, is key in this process. For most plants, it is an error to grow them with only a single wavelength of blue and a single wavelength of red. It can work, but plant vitality is reduced. It is also an error to overdose your plants the longer wavelengths of red – the so-called infrared. Plants only utilize the infrared for heat content and too much will cause stress if not overheating.
Effective output refers to the output power of a lamp in the target spectrum. For plants, incandescent bulbs have the least effective output. An HPS or MH bulb has a nominal effective plant light output of 78%, with the lower wattage bulbs (e.g., 400W) achieving less and the highest wattage bulbs achieving near 82%. The remainder goes mostly to long-wave and heat. So for example, a 900W incandescent bulb has an effective plant light output of about 725 Watts. In contrast, fluorescent full-spectrum bulbs in the 5000 Kelvin to 6500 Kelvin range have over 90% effective plant light output, with the T5 HO 6500K bulbs near 92%. LED systems have a low effective output of 65% to 75% since they completely miss the background spectrum needed by plants.
Diffuse light is preferred by plants as opposed to coherent light. Fluorescent bulbs output diffuse light, where as lasers are extreme examples of coherent light. Incandescent bulbs, spectrum shifters, and polarizers produce a mixture of the two.
The equivalent of outdoor sunlight is between 50 Watts per square foot and 75 Watts per square foot of effective output – projected at a distance of 1 meter. If your bulbs are closer then less is needed, if you are farther than more is needed. The distance relationship is not linear. For example, if you half the distance you still need about 70% of the output.
Projected area is the entire surface area illuminated by a bulb or series of bulbs. If your bulbs are uncovered (no hood) in a room 15’ x 15’ x 9’ high then the projected area is 990 square feet. If instead you have a robust mirrored hood that focuses upward and side output to the floor, then your projected area is about 225 square feet plus about 5% of the remaining 765 square feet for efficiency loss in the reflectance – a total of about 260 square feet.
Calculate the wattage you need by multiplying the number of square feet your bulbs will project onto by the target number of Watts / square feet, and then dividing by the effective efficiency of the bulb. For example, to achieve 75 Watts / square foot in the 15’ x 15’ x 9’ example room using a reflective hood over T5 HO lamps, we’ll need: 260 s.f. x 75 W/s.f. / 92% which is about 21 kW.
fmu65
10-31-2011, 06:27 AM
Amazing post! Thanks for breaking it down in such an easy to understand format!
Richard, it is obvious you know a lot about light, but it's not quite up to date with the newest LED growlight. First, most of the LED lamps don't only have red an blue LED's, but also white LED's. And when we are talking LED lamps, we are not using lumens anymore, but PAR (Photosynthetically Active Radiation). One of the really good thing about LED's, are that it's alot easyer to control that the plant gets the correct wavelength they needs.
I have read alot about LED growlamps, and there are _no doubt_, that the LED's outperforms both HPS and fluorescent lamps. LED lamps are very popular here in Denmark, and I know alot of people that have replaced there HPS and fluorescent light with LED's, and they have better results with the LED's.
And another very important thing with LED's are that they use alot less of energy, and it is very important to think of climate as we are in a climate crisis.
I have today just recieved my new 17w PAR 38 LED lamp to replace my "old" 50 watt UFO. It's impressive that a much smaller lamp can be that much powerfull, it's because it's use CREE LED's (USA made), CREE LED's are the best LED at the moment.
Brian
raygrogan
10-31-2011, 05:35 PM
Wow, great expertise. Now, in my case I don't want the plants (taro) to grow, just stay alive and stay relatively small during the winter. (Then in the summer, outside, is when I get my growth.) The only two tricks I know are keeping the pots relatively small, so plants are root bound, and keeping the light relatively low. So what kind of lights would be not "grow lights", but "fester lights"?
timmko
10-31-2011, 06:14 PM
I have both a T-6 unit and 400W MH bulbs. The MH bulbs are hotter and use more power but seem to do a little better. My T-6 unit has to be closer to the plants to be real effective but overall they are both great...Heres my link Hydrofarm T5 4FT Designer Fluorescent Grow Lights - Plantlighting Hydroponics & Grow Lights (http://www.plantlightinghydroponics.com/hydrofarm-t5-4ft-grow-lights-c-321_738.html)
nannerfunboi
10-31-2011, 08:14 PM
much thanks to all on experiences .. i am looking into the
LED grow lights too i know the europeans are way ahead of us
here in the states in lighting tech..ive checked out whats on ebay..
and there alot of low priced lights ..then the much higher end..
for me..i too just want to have the minimum lighting on overwintering
my tropicals..
i am interested in knowing the sucess of using LED's on seedlings..???
anyone???
great to have some dialog on this here!!!
thanks all
:goteam:
sunfish
10-31-2011, 08:55 PM
http://www.google.com/url?sa=t&rct=j&q=led%20for%20seedlings&source=web&cd=3&ved=0CDQQtwIwAg&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DdQcV9uya-2Q&ei=-lCvTqDQH6fliALhm-jgDw&usg=AFQjCNGyLJruUZAFP7SGAhSuOtkrH_pGNA&cad=rja
The Hollyberry Lady
10-31-2011, 09:18 PM
Whatever lighting you choose, make sure it suits your personal needs...and beware of people who appear as "experts", as these are often the people who know the least.
Do your research and you'll find something that's right for you. I use a metal halide HID system myself and have had success with everything from strawberries to cucumbers.
Good luck!
: )
Richard
10-31-2011, 11:53 PM
... First, most of the LED lamps don't only have red an blue LED's, but also white LED's. And when we are talking LED lamps, we are not using lumens anymore, but PAR (Photosynthetically Active Radiation). One of the really good thing about LED's, are that it's alot easyer to control that the plant gets the correct wavelength they needs. ...
I'm aware of all this. If you want to do a comparison, compute the power spectral density of any commercial LED system in the response spectra of plants and compare it to a 6500 Kelvin fluorescent.
And another very important thing with LED's are that they use alot less of energy, and it is very important to think of climate as we are in a climate crisis.
Less power in means less power out.
But to be fair, first compute how much wattage you need in effective output and then go out and find a system to meet it. Globally, the cost of choices varies.
Wow, great expertise. Now, in my case I don't want the plants (taro) to grow, just stay alive and stay relatively small during the winter. (Then in the summer, outside, is when I get my growth.) The only two tricks I know are keeping the pots relatively small, so plants are root bound, and keeping the light relatively low. So what kind of lights would be not "grow lights", but "fester lights"?
10 Watts per square foot of projected area.
Now, in my case I don't want the plants (taro) to grow, just stay alive and stay relatively small during the winter.
You can just buy a smaller LED lamp, a 12w lamp are today pretty cheap, and then increase the distant between the lamp and your plants.
i am interested in knowing the sucess of using LED's on seedlings..???
Yes, i make almost all my tropical plants from seeds, and at winter the only "sun" my seedlings gets, are from the LED growlamp. At february/march I also makes chili, peper and tomato seedlings.
Richard
11-01-2011, 12:18 AM
You can just buy a smaller LED lamp, a 12w lamp are today pretty cheap, and then increase the distant between the lamp and your plants.
Plants absorb light from the human visible spectrum, but (depending on the plant) in ratios of about 1/3 of the blue sub-spectrum, about 1/3 of the red sub-spectrum, and about 1/3 of the rest combined.
LED does not provide this. The LED's used in "plant" light fixtures are manufactured for telecommunication fibers. The bandwidth of each color is purposely very narrow.
the flying dutchman
11-01-2011, 08:21 AM
I guess Richard is right. I used the unscientific approach and checked
wich growlights are sold in Cannabis growshops in Holland. They all sell
400 and 600 watt bulbs, no LED lights. In my opinion they would be the
first to use led lights because they have enormous problems with all the
heath that the bulbs produce. The heath is easily detected by the police
who use infrared cameras in helicopters and if it snows the snow melts
from the roofs where they grow the Cannabis so that is suspicious too.
I do know however that some commercial crop growers are experimenting
with the LED lights, maybe they use a combination of Bulbs and LED's, if that makes sense?
Ron
stevelau1911
11-01-2011, 09:26 AM
I've tried getting the 90 watt UFO light, but it was very noisy with it's fan and eventually half the leds burnt out within a few days so I had to return it. I did find that the vegetative growth during that time on my plants seemed pretty solid especially for comparatively weak light. If you do get one, I would suggest going with the generation v type Blue Red 225 SMD LED Grow Light Panel 30w Indoor Garden Hydroponic Plant Lamp | eBay (http://www.ebay.com/itm/Blue-Red-225-SMD-LED-Grow-Light-Panel-30w-Indoor-Garden-Hydroponic-Plant-Lamp-/140626586779?pt=LH_DefaultDomain_0&hash=item20bdff6c9b)
It would suck to have a fan burn out or the lights stop working all of a sudden due to overheating, but from a week of using leds, I believe that a 90 watt led is by far more useful than a 70watt consuming cfl. Of course it's performance may be inferior to that of a true 400 watt metal halide, hps or any other commercial greenhouse light but I believe leds are pretty useful as long as you don't get the 9 watt consuming cheap stuff which is hardly sufficient for a night light.
JuniPerez
11-01-2011, 10:09 AM
I've had good luck with the el cheapo CFL's, just get a clamp lamp of some sort. Light weight, no heat to speak of.
Thanks Ray... I've got some spare CFL's from my old reeftank as well as some daylight & actinic bulbs... was just thinking of going LED instead.
JuniPerez
11-01-2011, 10:10 AM
Here is the scoop on lighting.
Thanks Richard... that's a lot of info.
JuniPerez
11-01-2011, 10:14 AM
Richard, it is obvious you know a lot about light, but it's not quite up to date with the newest LED growlight. First, most of the LED lamps don't only have red an blue LED's, but also white LED's. And when we are talking LED lamps, we are not using lumens anymore, but PAR (Photosynthetically Active Radiation). One of the really good thing about LED's, are that it's alot easyer to control that the plant gets the correct wavelength they needs.
Brian
Agree, the older LED lamp sets I used to see were red and blue... nowadays I see white included in there.
I didn't know about the PAR part of it though... I'll have to take that into consideration. Most places I look at use a lumens equivalent, I assume so that we can compare to the more familiar bulbs we're used to.
Thanks Brian... your info along with Richard's will definitely come well in handy, not just for myself, but for many folks here.
JuniPerez
11-01-2011, 10:20 AM
...The heath is easily detected by the police who use infrared cameras in helicopters and if it snows the snow melts
from the roofs where they grow...
Ron
Well, the cops around here like to take pictures posing with my banana plants and walk all over my cannas & elephant ears, so I definitely want to keep my growing operations on the downlow... don't want them up in here. XD
JuniPerez
11-01-2011, 10:26 AM
It would suck to have a fan burn out or the lights stop working all of a sudden due to overheating...
Yes, and I'm not home much, so a fan burning out isn't good... especially if I'm out of town
sunfish
11-01-2011, 11:51 AM
From what I have read led's will work fine to keep your plants alive through winter.Now if your growing mary jane you might not get a big crop.
JuniPerez
11-01-2011, 11:56 AM
From what I have read led's will work fine to keep your plants alive through winter.Now if your growing mary jane you might not get a big crop.
Lol... no Mary here... but I do have a Helen's growing... XD
Less power in means less power out.
No, it's not that simple. The reason that an HPS creates so much heat is because it wastes a lot of energy. The trick is of course to get as much out of energy as possible. LED's are constantly being improved, it is such therefore my new 17W LED cover a larger area than my old 50w LED. The old has 50 LED's, the new, only 12, yet the light of the new is much sharper.
LED does not provide this. The LED's used in "plant" light fixtures are manufactured for telecommunication fibers. The bandwidth of each color is purposely very narrow.
Some people just will not recognize new teknology. :) There are many different LED's, and you can get diffenret LED lamps with different LED's, you can not just say that telecommunication and LED lamps use the same LED's, thats to easy.
Why should I lie when I says LED lamps actually works? I'm not a LED lamps salesman or something like that. It's my third season using a LED lamp, I have around 150 small tropical plant in my basement and the temperature are around 20 celcuis. Some of them are musa velutina's, different species of musa sikkimensins and trachycarpus palms, they came from a cooler climate, so the will normaly not doing well 5-6 months in a hot basement during the winter without the energy from the sun also. Here they not just survive the long winter, but also grows very well.
If you have som sparetime, take a look at this danish LED lamp threat that started for 2 years ago, yes sory it's danish, but use Google translate to translate it. :)
Havenyt.dk - LED-plantelys (http://www.havenyt.dk/forum/drivhuset/6917.html)
To begin with, there were many skeptics, like here, but no more ...
I guess Richard is right. I used the unscientific approach and checked
wich growlights are sold in Cannabis growshops in Holland. They all sell
400 and 600 watt bulbs, no LED lights. Ron
Ron, have you tried searcing the words 'LED lamp' on Youtube? Then you will se alot of plants, and it's NOT banana plants. :)
I've tried getting the 90 watt UFO light, but it was very noisy with it's fan and eventually half the leds burnt out within a few days so I had to return it.
Like many other things, there are booth good and bad quality out there. It's OK that the lamp unit are made in China, but don't buy it if the LED's are made in China. Go for the CREE LED's (american made), it's the newest and best LED's for now. New LED lamps don't even had a fan, they don't need it.
Thanks Brian... your info along with Richard's will definitely come well in handy, not just for myself, but for many folks here.
You are welcome. :) It was not my opinion that this should eventually become so long an endless thread, if I knew it, I would never have written here. I just wanted to share my own personal experience with LED lamps.
Richard
11-01-2011, 06:41 PM
Some people just will not recognize new teknology. :) ...
Your criticism is misplaced. I am a paid consultant for both indoor and outdoor agriculture here in southern California. My indoor and greenhouse clients are expecting sound advice before spending $5k to $500k on hardware and materials. These people are very serious about results and expect detailed analysis and reports.
Here is what outdoor daylight looks like:
http://www.gelighting.com/na/business_lighting/education_resources/learn_about_light/imgs/distribution/outdoor_daylight.jpg
For many crops whether indoor or outdoor, it is an established fact that their utilized radiative energy input comes 1/3 from the blue sub-spectrum, 1/3 from the visible red spectrum, 1/3 of a fairly even mix of the wavelengths in between; and is optimal when delivered at a total radiant flux of 50W to 75W per sq.ft.
The manufacturers of LED plant lights have basically two types of systems: one for indoor ornamental plants with modest light requirements, and the other for indoor growers of a popular cash crop. LED manufacturers are good at reporting technical capabilities as required by law, but not forthcoming about the radiant flux produced by their systems. Instead, they prefer to represent performance in one number when in reality the situation has multiple criteria.
To make sure we have covered all the possibilities for our clients, we obtain LED systems from manufacturers reps in southern California and disassemble them. If you look at an individual diode, there is a number stamped into it which you can trace back to the manufacturer. The same by the way is true for other bulbs.
Two weeks ago I had a booth I had a booth at the Maximum Yield Indoor Gardening Expo held in Long Beach, California -- where it is legal to grow that funny indoor cash crop with an easily obtained license. All of the indoor plant light manufacturers and distributors were represented. In terms of LED system design or components I did not see anything new. One thing that is apparent at these conferences: the number of visitors to LED booths is small, and mostly composed of novice growers.
Now contrast that with the Worldwide Ag Expo held in Tulare every year. You won't find a single LED plant system on display even though the indoor factory cultivation of cucurbits (melons and squashes), tomatoes, herbs, lettuces, etc. is a huge and growing business. They are mostly focused on fluorescents except in northern or winter cultivation where the excess heat from HID lamps is a bonus.
Your criticism is misplaced. I am a paid consultant for both indoor and outdoor agriculture here in southern California. My indoor and greenhouse clients are expecting sound advice before spending $5k to $500k on hardware and materials. These people are very serious about results and expect detailed analysis and reports.
I don't think is misplaced at all, because how can you say it don't work, when you even have tried that technology by yourselv. It's not a new fantasy product, it's a product that have been on the market for som years now. But you continue to make your "technical facts", and just closing your eyes for the greath results others have with these lamps.
You don't need to commment on this, because i'm feeling I completely wasting my time here, so i'm out of this thread again.
The Hollyberry Lady
11-02-2011, 09:45 AM
Well the wonders never cease. Another growlight thread ruined again!
: (
Richard
11-02-2011, 11:26 AM
I don't think is misplaced at all, because how can you say it don't work, when you even have tried that technology by yourselv. It's not a new fantasy product, it's a product that have been on the market for som years now. But you continue to make your "technical facts", and just closing your eyes for the greath results others have with these lamps.
You don't need to commment on this, because i'm feeling I completely wasting my time here, so i'm out of this thread again.
:ha: Haven't tried it? In conjunction with the San Diego Growers consortium we've tested every indoor lighting configuration and fertilizer program available to date.
Some people like to keep it simple and garden by word-of-mouth recommendations and information that comes across in popular culture. Go for it! Have fun! Experiment! On the other-hand: if you are going to use here-say statements to publicly reject technical results, then expect a protracted rebuttal.
JuniPerez
01-15-2012, 09:19 PM
Okay, I've had over a couple months to grow my plants under both, the old 96w CF lighting hood from my old fish tank AND my new growspot LED lights (3 bulbs @ 12w each, daylight, blue, and mixed spectrum). Each table setup is across the same room from each other. I see no difference between the plants under each type. As far as the bulbs go, the LED lights require no fan and don't get hot... the CFs have a fan running to keep 'em cool. I don't know if a couple months is not enough time to see differences in results, but so far I'm sold on the LEDs. I've got seedlings from bananas, passion vines, and a few trachycarpus species. The bulbs went on sale after I bought them, so I should've bought a couple more... I'll catch them next sale.
stevelau1911
01-15-2012, 10:30 PM
Are 3 (12 watt) led lights really strong enough to prevent a large houseplant from etoliation?
I did buy a 7 watt led light which was basically a regular light head with red and blue christmas light a few years ago, and it wasn't even sufficient for a night light let alone help plants grow. The 90watt UFO led light is strong enough, but the fan is noisy, and if the fan fails, the light is toast, but mine stopped working after a couple days.
I find that cfls, even up to 85 watts give out a decent amount of light, perhaps around 5000 lumens per 85watt bulb and don't get that hot or require a ballast, but I'm only using a 23 watt cfl now because I'm just starting blueberry & sarracenia seeds that haven't sprouted yet with it. CFLs seem to work fine for me so unless I find a led light that works better, I'm sticking to cfls.
Richard
01-15-2012, 10:56 PM
Are 3 (12 watt) led lights really strong enough to prevent a large houseplant from etoliation?
I would agree that the performance of any lamp with seedlings is no indication of results with mature plants.
... I find that cfls, even up to 85 watts give out a decent amount of light, perhaps around 5000 lumens per 85watt bulb ...
Lumens are a measure of human perception of brightness and not energy supplied to plants. A more useful value is the input/output watt efficiency. Both the LED's and CFL's are in the low 90% which is excellent. In terms of cost of output watts in appropriate wavelengths per square foot at 1 meter -- the LED's are not competitive.
JuniPerez
01-16-2012, 10:01 AM
Are 3 (12 watt) led lights really strong enough to prevent a large houseplant from etoliation?
I have no idea, but I am only using them for seedlings. As far as I can see, the three 12w bulbs are brighter to my eyes than the CF fixture. I have a crappy light meter somewhere around the house, but up to now haven't even thought about measuring. The larger plants, like my dwarf orinoco, dwarf PR plantain, SDC, etc, are all in another room with large southern windows, so no need for the lights.
harveyc
01-17-2012, 01:03 AM
Let me make it clear that I claim to have no expertise in grow lights! :)
I was looking into indoor grow lights for my home as well as a small grow area in my shop a few months ago. I haven't bought anything yet but will likely buy some indoor LED lights just for a few spots that are a pain to change since they will likely last longer. I like to read reviews of products on Amazon as there are often some very useful information, especially since folks can comment on a product's feedback if they don't agree, etc. Okay, less anyone think I'm posting here to try to sell Amazon stock.... I came across the review of one LED light where I came across a review by someone who managed the building operations of a large gambling casino. I don't recall the precise details, but he mentioned that LED output dropped significantly after something like a year. This casino went back to CFL. I was surprised to read that LED output drops off even though these lights have ratings of very long lifespans.
I'm not particularly pleased with the performance of CFL lights in my house either. Many bulbs fail in less than a year though most last many years. At least their initial cost is very low in comparison to LED.
I'm not anti-LED. I've got a LED flashlight with 2200 lumens and am very pleased with it. I other small ones as well.
Okay, for my own example, I'd like to light an area of 3' x 6' with lights suspended 3' above the growing area with cheapo aluminum reflectors. What number and kind of CFL bulbs can I get by with. I'm growing a miracle fruit plant and tomato starts. Links to product sources would be appreciated. Links to products on Amazon would also be appreciated! ;)
Thanks.
JuniPerez
01-17-2012, 07:33 AM
I don't recall the precise details, but he mentioned that LED output dropped significantly after something like a year.
I had read that they lose half their brightness after about 5 years of constant 24hr/day use. CFL's supposedly lose 20-40% by the end of their lifespan. Maybe this will improve?
Richard
01-17-2012, 11:23 AM
I had read that they lose half their brightness after about 5 years of constant 24hr/day use. CFL's supposedly lose 20-40% by the end of their lifespan. Maybe this will improve?
I prefer the 4' fluorescent tubes (6500K, high output) to the compact fluorescent (CFL) bulbs for indoor plant growth. However, the CFL's would be great for a batch of seedlings.
Richard
01-17-2012, 02:20 PM
(Following up on a PM question from Harvey)
Regardless of the kind of light you choose, keep the following in mind:
Lumens is a measure of the perceived coherency of light on a surface. It does not depend directly upon energy imparted to the surface.
Photosynthesis depends directly upon the energy (watts x seconds) of light in the "plant spectrum" (6500K black body) imparted to the surface. It does not depend upon lumens.
sunfish
01-17-2012, 02:57 PM
(Following up on a PM question from Harvey)
Regardless of the kind of light you choose, keep the following in mind:
Lumens is a measure of the perceived coherency of light on a surface. It does not depend directly upon energy imparted to the surface.
Photosynthesis depends directly upon the energy (watts x seconds) of light in the "plant spectrum" (6500K black body) imparted to the surface. It does not depend upon lumens.
Watt ?:ha:
sunfish
01-17-2012, 03:23 PM
Lumens=a measure of the total "amount" of visible light emitted by a source.
harveyc
01-17-2012, 11:36 PM
Watt? My only reference to lumens was in reference to my flashlight. I only use my flashlight to emit light which I can see so that I can find my way around my fields, etc. I have not tried growing plants using flashlights and don't anticipate doing so.
I'm still looking for a reference/link to a source of some light I can use to cover a 2' x 4' area.
harveyc
01-23-2012, 03:08 PM
I'm still looking for a reference/link to a source of some light I can use to cover a 2' x 4' area.
Watt the heck, I settled on http://www.amazon.com/HydroFarm-FLT48-Commercial-System-Fixture/dp/B002TJKS8Y/ref=pd_sbs_ol_1 which should get here on Wednesday. Seems good enough.
sunfish
01-23-2012, 03:15 PM
Watt the heck, I settled on http://www.amazon.com/HydroFarm-FLT48-Commercial-System-Fixture/dp/B002TJKS8Y/ref=pd_sbs_ol_1 which should get here on Wednesday. Seems good enough.
I would think that would work PRETTY GOOD. Wish I had one.:woohoonaner:
venturabananas
01-23-2012, 09:12 PM
Watt the heck, I settled on Amazon.com: HydroFarm FLT48 Commercial System Grow Light Fixture: Home & Garden (http://www.amazon.com/HydroFarm-FLT48-Commercial-System-Fixture/dp/B002TJKS8Y/ref=pd_sbs_ol_1) which should get here on Wednesday. Seems good enough.
For my more modest needs, I got this one last year. It seemed fine, the plants grew and seemed happy enough, though without any reference for comparison, I have no idea how good it is.
Amazon.com: Hydrofarm JSV4 4-Foot Jump Start T5 Grow Light System: Home & Garden (http://www.amazon.com/Hydrofarm-4-Foot-Start-Light-System/dp/B0001XLSGQ/ref=sr_1_2?s=home-garden&ie=UTF8&qid=1327370699&sr=1-2)
David Harritz
06-01-2012, 01:38 PM
I am using the led grow lights at present and are working very well for me. It is giving great results to me and the plants are growing very well. If the led light do not suit you than there are other options like the fluorescent lights.
coronelcarina07
09-27-2013, 02:00 AM
You can have more options at Grow Blu (http://growblu.com/)
Abnshrek
09-27-2013, 04:21 AM
You can have more options at Grow Blu (http://growblu.com/)
You can probably burn your place down too.. :^)
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