View Full Version : LED Grow Light
Greenmtnboy
10-17-2012, 12:50 PM
Hello everyone,
New guy here from Vermont. I purchased a banana plant (I think it is a red abyssinian) at my local greenhouse this summer and had it living on my deck until the temperatures started dropping. Its now living in the corner of my living room next to a huge window and sliding glass door. It looks like the red color is fading and it for sure has slowed its growth way down. I cut back on fertilizing it but I'm worried it is not getting enough light. I'd like to purchase a grow light to hang from the ceiling over it...which brings me to my question.
What is the difference, if any, between the blue, red, white, or mixed color LED grow lights I am seeing advertised online? Do bananas have a color preference?
Also, my house is kept a bit on the cooler side...should I be providing some sort of supplemental heat to the bottom of the pot?
Thanks in advance,
Lucas
LilRaverBoi
10-17-2012, 03:25 PM
I wouldn't recommend LED grow lights period. As far as I'm concerned, they're crap.
Abnshrek
10-17-2012, 04:24 PM
Is the window and sliding glass doors on the south side?
I think LED's stink too. :^)
sunfish
10-17-2012, 04:31 PM
LED's are the best someone told me
sunfish
10-17-2012, 04:34 PM
LED Grow Lights | Grow Lights by Hydro Grow (http://www.hydrogrowled.com/)
sunfish
10-17-2012, 04:40 PM
Can you grow marijuana with LED grow lights? | Grow Weed Easy (http://growweedeasy.com/LED-grow-lights-marijuana)
And the plants look kewl under the colored lights
sunfish
10-17-2012, 04:46 PM
The Lowdown on LED Lighting (http://www.led4growth.com/The-Lowdown-on-LED-Grow-Lighting.htm)
sunfish
10-17-2012, 05:09 PM
LED Grow Lights for Dummies (http://www.squidoo.com/led-grow-lights-for-dummies)
Greenmtnboy
10-17-2012, 05:15 PM
Thanks everyone!
So there seem to be two camps here. For those who don't like LED's could you make a suggestion of something that you do recommend?
raygrogan
10-17-2012, 06:03 PM
For cheapsters - I like regular old CFL light bulbs in various fixtures inc clamp lamps. The sweet thing is they are so cool, the plants (taro) can grow right up to them. No power usage to speak of. And I have about 6 of them, 60W = 13W actual, on a simple timer and 16/2 cord. But it is not much light from a plant's point of view, with this plus a window facing SW they mostly just fester waiting til spring.
brothertom2020
10-17-2012, 06:46 PM
Howdy: after looking this post over and reading the info made available, methinks they are over priced and over hyped. I'd put my nanner near the brightest window you have available and watch it for few weeks.
It will tell you real quick if it is happy or not! Tom
austinl01
10-17-2012, 09:30 PM
Pretty darn neat, Sunfish!
LilRaverBoi
10-17-2012, 10:26 PM
For the cheaper option, try fluorescent bulbs. Look for full spectrum bulbs, or those rated at a color-temp around 6500K. Some types of bulbs are specifically marketed for use with plants. If you want to get really serious, buy a high pressure sodium (HPS) or metal halide (MH) set-up.
You might just wanna wait at this point and see how things do without lights.
Oh and pretty sure Tony is being facetious about supporting the LED's.....take the literature provided for what it's worth (and with a grain of salt).
Abnshrek
10-17-2012, 11:14 PM
I'd do T-5's before I shelled out that kinda $$ for LED's. They have 6500 bulbs. :^)
Greenmtnboy
10-18-2012, 01:28 AM
Okay...so here is my next question. What is the difference between T-5, T-8, T-10, and T-12 bulbs? Is one better for growing bananas?
I looked at HPS fixtures online but my concern is that they get too hot and use too much electricity!
jmoore
10-18-2012, 01:43 AM
I think I'm having de ja vu...isn't this where Richard gives his sage like advice...
MUST USE SEARCH
seriously this has been discussed ad nauseum on canna sites
every single possible facet has been rehashed including iggits who use $200 CMH for the improved UVA UVB output only to place it in a glass cool tube therefore filtering the improved chromaticity right out of existence
:lurk:
t5-8-12 are diameters
T12 is dinosaur nuff said
t5 is only HO with high ambient temps generated by an enclosure THIS MEANS NOT BETTER
T8 is the most common and cheapest for bulbs, ballasts, etc
T832W is the bulb part # prefix
CFL is cheap and available but harder to reflectorize
HPS is most efficient and a burst and fire hazard if not enclosed
MH is a waste of time with all the cons of HPS and none of the pros
electricity use is defined in watts
a 150w HPS uses the same amount as 150W of fluorescent
the HPS will give slightly more LUMENS PER WATT (this is how you get a real answer)
everything is nearly half price if you go to a local electrical store, not a box store
LED=hype
Yuri Barros
10-18-2012, 04:22 AM
Check it out.................Kessil Leds..............
Kessil Lighting- The Spectral Revolution (http://www.kessil.com/products/h150w_led_grow_light.php)
It´s a Dense Matrix stuff...................looks very nice product.............
And they have may spectral choices.................
Greenmtnboy
10-18-2012, 04:28 PM
Thanks for all the suggestions and wonderful links...but taking into account electricity usage, heat output, and initial investment I think I'll be using a T-5 fixture for now!
Did anyone weigh in on bottom heat?
EDIT
I really butchered this final draft.
The post was supposed to be a lot less vitriol.
I've been trying to cram the most info with the least words. Sometimes it doesn't sound right.
I'm going to take the winter off from bananas and write some tutorials on a couple subjects on which I can speak authoritatively. Some of the info here is lacking or scattered.
Hope this post didn't turn anyone off.
I think I'm having de ja vu...isn't this where Richard gives his sage like advice...
at the risk of sounding like a jerk
maybe Richard got tired of teaching + and - in his calculus class
This will be my final post on lights until I find a way to distill this complex subject. Maybe I'll make a ULTIMATE GUIDE post and just permalink.
it has become clear that people understand neither lumens per watt nor watts consumed
this is really simple math
if both lights A and B consume the same watts,
if light A makes 95 LPW and light B makes 105 LPW then light B is clearly more efficient and light A probably making more heat
simple
go to the local electrical store and buy
150HPS ballast $23
150HPS universal mounting bulb MEDIUM base $5-10
medium base socket $3
can you get a T5 for $35? NO
be sure to put those T5 light within a foot of the leaves.
this may be too complicated Inverse-square law - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Inverse-square_law)
this is better
Rules for Perfect Lighting: Understanding The Inverse-Square Law (http://photo.tutsplus.com/articles/lighting-articles/rules-for-perfect-lighting-understanding-the-inverse-square-law/)
here is the meat
According to the law, the power of the light will be inversely proportional to the square of the distance. So if we take a distance of 2 and square it, we get 4, the inverse of which would be 1/4 or rather, a quarter of the original power – not half.
LIGHT INTENSITY AT 2FT IS 1/4 LIGHT INTENSITY AT 1FT
you must have these flouros nearly touching or you are wasting time and money PERIOD
HPS is more forgiving as a point source inside a cone reflector (but does not circumvent this law)
good luck with your lights
Inverse square is only for a point source (or similarly compact source of any shape). If you're moving a linear source (like a fluorescent tube) away from an object to be illuminated, then the light intensity is inverse linear as long as the length of the source is much greater than the distance to the object. If you're providing lighting to an entire room, distance is irrelevant: an array of supplemental lights five feet above an expanse of tables in a greenhouse will provide the same amount of light as it would if it were eight feet above the tables.
hogwash
I provide links to scientific laws and mathematical equations and you make some mushmouth post with weasel words like the light intensity is inverse linear as long as the length of the source is much greater than the distance to the object.
yeah so if a train leaves a station going MUCH faster...
next
an array of supplemental lights five feet above an expanse of tables in a greenhouse will provide the same amount of light as it would if it were eight feet above the tables.
Since the most common flouro lengths are 4ft and 8ft you may want to rethink this statement.
Unless five is MUCH less than four, or eight is MUCH more than eight.
flouro tubes ARE a point source so long as they are horizontal in relation to a horizontal canopy
We (when I say WE I refer to everyone in the world using actual math) are measuring distance from plants to lights.
So long as the canopy and tubes are parallel then the distance will be identical to a point source with the exception of reduced intensity light from for example the opposite end of the tube.
If you apply inverse square then you will see this is very little.
Hell if you apply inverse linear it's plain as well.
If you're providing lighting to an entire room, distance is irrelevant: an array of supplemental lights five feet above an expanse of tables in a greenhouse will provide the same amount of light as it would if it were eight feet above the tables.
Similar to saying that sprinklers will fill a bucket as fast as a hose put directly in the bucket.
No one is trying to find their shoes across the room here so once again your statement holds no water.
We are NOT providing light to the entire room, we are lighting the leaves of a plant which is presumably under the light.
Anyone who has ever seen a reflectorized light can see that your statement cannot apply.
Too reiterate my previous points.
HPS currently rules the indoor plant world with the benefit of radiant heating if you are overwintering in an outbuilding.
The cost of running a 600W will be less than replacing your bananas come spring and they might never realize it's winter.
Flouro lights are OK.
CFLs can be refelctorized and hung individually over each plant or t8 tubes provide good output with low initial investment and easily sourced parts.
BE SURE TO GET THE LIGHTS AS CLOSE AS POSSIBLE WITHOUT SCORCHING.
8ft away is a joke.
I apologize the the forum members if this post seems undeservedly vitriol.
I would be lying if I said I wasn't mad to receive a email telling me that someone with 7 posts came to dilute my comment with mush mouth psuedo science gobbeltygook.
I tried to make the best, most scientifically and empirically supported post in hopes of benefiting everyone here. I've been working on some stuff to post in the wiki come spring, mostly trying to remove all the cannabis related material as I find it inappropriate.
This is proving much harder than my Link-O-Rama idea.
If DSWS would like to post links, research and other information then I would be VERY happy to have been educated, even at the expense of looking like a arse for this post.
Knowledge is far more important than my ego.
It only takes high-school math to derive the inverse square law.
When you talk about a four-foot-long fluorescent light having to be within inches of a plant, it's inverse linear.
jmoore
12-07-2012, 01:05 PM
Like I said..."de ja vu!"
It only takes high-school math to derive the inverse square law.
I'd consider this an ad hominem attack if we were standing in the same room and I'll treat it as such here. http://i448.photobucket.com/albums/qq209/Tejrinde/Emoticons/Slap/smiley-slap.gif
This from a guy who says things like....
Ash is full of potassium. Perhaps an influx of potassium helps. Has anyone had good results with potting media that have lots of potassium ...?
:ha: :ha: :ha:
The seeds seem too large to survive chewing, so I don't think passage through the gut of an animal is the normal trigger for germination.
I encourage you to try chewing some.
Be sure to post a pic of your teeth when done.
:lurk:
I'll not have my busy day held hostage by someones refusal to post more than a single sentence reply or attack my intelligence so I'm done with this thread.
I'm even a little sorry I ever tried to help.
Be forewarned folks that if dsws cannot explain, articulate, and post links evidence to back his points then his statements should be disregarded.
See you ladies in the spring.
sunfish
12-07-2012, 03:52 PM
I learn something new everyday
Inverse Square Law for Light (http://hyperphysics.phy-astr.gsu.edu/hbase/vision/isql.html)
jmoore
12-08-2012, 05:57 AM
It works for protons and neutrons, so should also work for light.
I just noticed the edit to #22. If I had seen it before posting #23, I wouldn't have been so short. I expect to get something posted on Monday, either a link or a more detailed explanation of the transition from inverse-linear to inverse-square with increasing distance to a linear source of finite length.
I'll write this so it will (I hope) be intelligible even if the picture doesn't show. My apologies for the redundancy, if it does.
http://www.bananas.org/gallery/watermark.php?file=51639
To find the intensity of light from a linear source, first draw a perpendicular to the source going through the point where you want the intensity. (In the diagram it's on the source, but that's not necessary. If not, you just subtract the term that's off the end instead of adding.) Call the distance from the observer to the source along the perpendicular D, and the lengths of the parts of the source on either side of it L1 and L2. Call the angles from the perpendicular to the ends of the source A1 and A2.
Intensity is proportional to angular area of the source. (Apparent brightness is constant with distance, because both the apparent size and the amount of light from each infinitesimal bit of area decrease as the square of distance.)
The tangent of A1 is L1/D, and the tangent of A2 is L2/D. So A1 is arctangent of L1/D, and A2 is arctangent of L2/D. Width is negligible, so angular width is proportional to 1/D. Intensity is arctan(L1/D)/D + arctan(L2/D)D.
This video shows essentially the same formula, arrived at by taking the inverse square law as given and just doing the calculus: From inverse square to inverse linear - YouTube (http://youtu.be/eBl4x_7DMto)
So for example, consider a point at six, twelve, and eighteen inches below a 48-inch fluorescent tube, one-fourth of the way along. I'll put the lengths in multiples of 6", and calculate relative intensities compared to 6" below. The relative amounts of light are
6": (arctan(2) + arctan(6))/(arctan(2) + arctan(6)) = 1
12": (arctan(2/2) + arctan(6/2))/2(arctan(2) + arctan(6)) = 0.405
18": (arctan(2/3) + arctan(6/3))/3(arctan(2) + arctan(6)) = 0.225
By inverse-square, it would be 1, 1/4, 1/9.
Note that by going from 18" up to 12" below the light, the brightness increases by a factor of 1.8, whereas inverse square would give 1.75. So it hardly makes a difference when comparing those distances. But when you go from 18" to 6", inverse square would give you a nine-fold increase in brightness, whereas it actually increases only by a factor of 4.4. Inverse square is off by a factor of two.
Anyone who has ever seen a reflectorized light can see that your statement cannot apply.
The kind of situation I was describing, as the limiting case where the height of the lighting doesn't matter at all, is like the picture on this page:
Food Production (http://www.charismac.com/instrument/index.php?option=com_content&view=article&id=57&Itemid=66)
Note that the reflectors only extend level with the lights, to intercept light that would go up and be wasted. They don't block light to distant parts of the greenhouse floor. The array of lights in that greenhouse is high enough to accommodate all the equipment they use, and the full height they want to grow their palm trees to.
If it made an appreciable difference in energy cost, they could have set it up to be able to lower the lights when the plants are small. But it doesn't. The cost of supplemental lighting for a square mile of agricultural greenhouse is the efficiency of your lights times the price of electricity. Losing light upward lowers the efficiency. Reflecting light straight down, with a reflector that absorbs part of the light, when it could have gone sideways and hit a different plant, also lowers the efficiency. Having the light go through a few extra feet of air doesn't.
No one who's setting up a large-scale operation like that would get their engineering off an internet forum, so it's presumably not a situation that anyone here is facing. But limiting cases are often useful for understanding.
jmoore
12-10-2012, 02:51 PM
Very nice, now let's move on from grow lights and talk about germinating banana seeds.
Lights is a very contentious issue and has been the source of many a disagreement (goodness knows why). For some reason some people get very hot under the collar about it (again, goodness knows why) so let's put it to bed and why don't you tell us a bit about yourself. Where are you from? What are you growing?
I'm growing, um, a spider plant and a pothos. I bought a bunch of seeds, including some bananas, and I found this site when trying to find out how to get them to germinate.
Unfortunately, I know diddly about germinating banana seeds. I discuss it at length in http://www.bananas.org/f16/insights-seed-germination-86-post210932.html#post210932, but as I say there, it's idle speculation.
The most striking thing to me about the banana seeds is that they're so large. Not peach-pit large, but still, pretty big. I wouldn't expect something that size to survive in the soil for a long time without something finding a way to eat it, or to make it through most animals' digestion. But it looks as though it makes for very vigorous seedlings when they do germinate.
I've been a stay-at-home dad for several years -- long enough that I should call myself unemployed now instead. My degree is in math, but I've learned a fair amount of biology, since that's what my wife works in. I'm in Boston, in a dinky apartment: the plants are stuck indoors without so much as the prospect of a balcony in the spring.
jmoore
12-11-2012, 02:33 AM
There is lots of information on germinating banana seeds, all very helpful, but you have to look for it. Good luck with the seeds.
Thank you dsws for your excellent write up.
This is the best explanation I have seen on that topic and it would make a wonderful addition to the wiki.
I'm coming back with a large edit but nothing critical, just need to soak this in so I can make a coherent response.
Edit:
Ignore this. I plugged in some smaller values for the distance, and got negative answers. Odds are, I won't figure out what went wrong until after the holidays.
Original post:
The case of a two-dimensional (rectangular) light source is harder. It's more formula than I can type into a calculator without making mistakes. I think I've got it working right on a spreadsheet. I'm going to be away over the holidays, and probably won't get back to playing with this before I go, so I'll post what I've got.
I put labels in the top row, then in the second row I have the length of the source, width of the source, and distance to the source in cells A2, B2, and C2. Then here's the formula for cell D2:
acos(((-B2^2-C2^2)*A2*B2+A2*C2^2*B2+A2*B2*(-A2^2-C2^2))/sqrt(((-B2^2-C2^2)^2+A2^2*C2^2+A2^2*B2^2)*(A2^2*B2^2+C2^2*B2^2+(A2^2+C2^2)^2) ))-PI()/2
That's for a point under one corner of the rectangle. For a point in the interior of the rectangle, just divide the big rectangle into four little rectangles with their corners over the point. I haven't done that yet.
I've only figured out the formula with some geometric reasoning and looking up a theorem or two: I haven't checked it by doing the calculus. I won't absolutely trust it unless I do so, but at least I've checked on the spreadsheet that it approaches inverse square when the distance is big, and constant when the distance is small compared to both dimensions of the light source. And it varies correctly with the area of the light source when the distance is large. So it should be right.
jmoore
12-21-2012, 02:25 AM
Did I miss something? I thought you said it was inverse linear, not inverse square.
Inverse square is when the light comes from a single point. Inverse linear is when the light source is a line, extending forever in both directions.
When a light source of any shape is very far away (compared to its size), it's effectively a point source. So whatever formula I come up with for a rectangle or a line segment or whatever, one of the things to check is that it gets close to inverse square when the distance gets big. That was the factor of 1.75 versus 1.8 in the 48"-fluorescent example: at only 12" to 18" away, it's already almost inverse square. Farther away than that, you can forget about the complicated stuff.
Inverse square for a point source is also used to figure out the other cases. You can get the amount of light from any source by adding up the amount of light from all the points of the source. But adding up infinitely many things can be very difficult sometimes.
In the case with the diagram, the light source is just part of a line. When you're really close to the line it's almost as though the line went on forever. So it's almost inverse linear in that case. When you're really far away from the line, it's almost as though the line was just a point. So then it's almost inverse square.
I think the mathematical formula is right, but the spreadsheet coding was wrong. Here's another attempt:
=ACOS(-(B2^3*A2+C2^2*A2*B2+A2^3*B2)/SQRT(((B2^2+C2^2)^2+A2^2*C2^2+A2^2*B2^2)*(A2^2*B2^2+C2^2*B2^2+(A 2^2+C2^2)^2)))-PI()/2
I still haven't checked it with calculus, though.
coronelcarina07
06-03-2013, 02:47 AM
You can try LED Grow Lights | Apollo LED Grow Lights (http://growblu.com/)
Howard007
08-02-2013, 01:43 PM
<<< t5-8-12 are diameters
T12 is dinosaur nuff said
t5 is only HO with high ambient temps generated by an enclosure THIS MEANS NOT BETTER
T8 is the most common and cheapest for bulbs, ballasts, etc
T832W is the bulb part # prefix
CFL is cheap and available but harder to reflectorize
HPS is most efficient and a burst and fire hazard if not enclosed
MH is a waste of time with all the cons of HPS and none of the pros
electricity use is defined in watts
a 150w HPS uses the same amount as 150W of fluorescent
the HPS will give slightly more LUMENS PER WATT (this is how you get a real answer)
everything is nearly half price if you go to a local electrical store, not a box store
LED=hype >>>
Unfortunately much of the above info posted here is highly opinionated and not factual. And the closing "LED=hype" remark is just silly and not even close to reality.
coronelcarina07
09-27-2013, 01:53 AM
You can check out LED Grow Lights | Apollo LED Grow Panels | UFO Grow Lights (http://growblu.com/)
Nathan1023
02-16-2014, 02:49 PM
Generally, I've heard that blue (>6000K or metal halide) light is best for vegetative growth, and red (<3000K or high pressure sodium) light is best for flowering/fruiting. LED's usually have blue and/or red lights. Reading Amazon reviews, it seems like you get what you pay for. Some are less that $30, but the reviews say that they're completely worthless, while some are over $1000, but the reviews are phenomenal. I've talked a lot about this with the owner of my local hydroponics store (Home (http://www.luckyroots.com)). He said he bought a Kessil, but after testing it under a light meter, decided not to sell it. He said that some brands he tested put out lots of Photosynthetically Active Radiation (PAR) at one specific distance, but much less at other distances. Others were more stable across different distances. In practical terms, this means that the top of your plant might do really well, but the rest of it won't, unless you get an LED whose PAR remains stable across distances. PAR is really what plants use. Lumens are just what humans see. More lumens usually means more PAR, but not always.
Moffaka
03-13-2018, 10:49 AM
Can you grow marijuana with LED grow lights? | Grow Weed Easy (http://growweedeasy.com/LED-grow-lights-marijuana)
And the plants (http://napasechnik.com) look kewl under the colored lights
What color spectrum should prevail?
Nathan1023
04-14-2018, 06:41 PM
It depends on what stage of growth your plants are in. More blue for veg; more red for flowering.
subsonicdrone
04-15-2018, 06:17 AM
just thought i would put this here as i watched it only a couple days ago
finally heard a good review although i have not seen a good led set up in person i have heard of real results... very specific units only.. dont know the brand/model sorry
until i see more proof my opinion of them is the same as some of the first replies
https://www.youtube.com/watch?v=mOQ2SmaDLOY
UVLAN is an issue no matter the source i guess
i do have a bit of light leakage and i sleep next to the plants
Livermore's Centennial Light Bulb (http://www.centennialbulb.org/)
aruzinsky
04-15-2018, 11:17 AM
http://www.general-cathexis.com/images/SDiggingShovel.jpg
https://www.youtube.com/watch?v=ifGdAcDryXk
Good scientists and engineers have terse speaking and writing skills because those skills are needed to author papers in peer reviewed journals where publication space is in high demand and low supply.
aruzinsky
04-15-2018, 12:02 PM
The main health concern about LED household lighting is that too much blue interferes with people's circadian rhythm. Some manufacturers have addressed this by replacing some of the blue and red wavelengths with violet wavelengths near 400nm. I consider this a sales gimmick like "made with sea salt" and "gluten free." Plants prefer red (660nm) and blue (450nm) to violet (400nm) therefore the "healthy" bulbs are not so good for plants.
http://www.ledsmagazine.com/articles/print/volume-14/issue-5/features/blue-free-light/blue-free-white-light-breaks-the-paradigm-of-circadian-lighting.html
speakeasy
04-17-2018, 05:24 AM
The main health concern about LED household lighting is that too much blue interferes with people's circadian rhythm. Some manufacturers have addressed this by replacing some of the blue and red wavelengths with violet wavelengths near 400nm. I consider this a sales gimmick like "made with sea salt" and "gluten free." Plants prefer red (660nm) and blue (450nm) to violet (400nm) therefore the "healthy" bulbs are not so good for plants.
http://www.ledsmagazine.com/articles/print/volume-14/issue-5/features/blue-free-light/blue-free-white-light-breaks-the-paradigm-of-circadian-lighting.html
I use software on my computer to gradually change the color temperature on my screen for this reason. https://justgetflux.com/
I grow in the vegetative phase with 4000K lights which are pretty neutral (I also have some 2700K lights). But I make sure they're off at 7pm. And I agree with you, the problem with violet at 400nm is that's where chlorophyll absorption rates start to drop off.
aruzinsky
04-17-2018, 10:26 AM
I use software on my computer to gradually change the color temperature on my screen for this reason. https://justgetflux.com/
I grow in the vegetative phase with 4000K lights which are pretty neutral (I also have some 2700K lights). But I make sure they're off at 7pm. And I agree with you, the problem with violet at 400nm is that's where chlorophyll absorption rates start to drop off.
The backlighting in LCD monitors and TVs (and, maybe, smartphones?) is currently the same as the light emitted from typical household lighting bulbs, either fluorescent or LED. Possibly, the manufacturers of those monitors will switch to the violet rich LED lighting and then you can keep the color temperature on your screen high.
I aesthetically prefer 8000K household lighting and use Sylvania Sky White fluorescent, when I can. Blue is my favorite color.
https://www.youtube.com/watch?v=gKrlRCH_M00
Another reason that I like Sylvania Sky White is that they emit no yellow wavelengths near 590nm, which improves the appearance of Caucasian skin by deaccentuating yellow blotches. Maybe, that explains the popularity of GE Reveal Incandescent bulbs which also emit no light near 590nm.
There is some evidence that wavelengths near 590nm are bad for plants.
https://www.ncbi.nlm.nih.gov/pubmed/16660793
https://jxb.oxfordjournals.org/content/58/12/3099.full.pdf
In this paper, all light between 500 nm and 600 nm, is called "green" and some of the bad effects attributed to "green" are actually attributable to yellow near 590nm. Note:
"Dougher and Bugbee (2001). The study compared the growth of lettuce (Lactuca sativa) seedlings under metal halide and high pressure sodium lamps. When conditions were compared, appreciable differences in dry mass, leaf area, and chlorophyll content were noted. However, the light conditions were identical in terms of calculated phytochrome photoequilibrium, blue light, red light, far-red light, and relative ratios between them. The only difference was a significant component between 580–600 nm. The authors conclude that this band of wavelengths generates negative effects on plant growth, in agreement with the green light data presented in Went (1957) and Klein et al. (1965). These reports present a common theme of a negative role for 500–600 nm light in plant growth."
DenaKessler
06-21-2018, 03:45 AM
What color spectrum should prevail for grow (https://bestmjseedbank.com/wtb/)?
Red for flowering.
cincinnana
06-24-2018, 05:21 PM
I had stopped by the hydro store.
I picked up some pearlite and some other stuff.
A nice variable 6x6 setup retail was 1600.00 out the door.
I was impressed with the knowledge of the store personnel.
ChristopherAndrews
05-21-2019, 04:46 AM
Light Emitting Diode (LED) grow lights are a sort of vitality productive lights that is a possibility for indoor cultivators. In contrast to different kinds of develop lights, LEDs don't consume a fiber, yet rather go light through semiconductors to make their range. Driven grow lights (https://www.slyng.com/users/eleanorveronica) can be utilized as the sole methods for lighting in a developing activity, as an enhancement to common light, or matched with different kinds of develop lights.
In contrast to different sorts of develop lights, light transmitted by LEDs can be centered, so none is scattered or lost between the knob and the shelter of the plants. LEDs have long administration lives, with knobs enduring from 50,000 to 100,000 hours of constant use.
subsonicdrone
05-22-2019, 10:24 AM
This led thread really attracts spam
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