Time to run some tests Rev! 1st start collecting data on what you currently are doing and write it down somewhere!

A few reference charts in one handy topic! All from wiki. Visible light is 400 to 700 nm.


Name...............................Abbreviation...............Wavelength range in nanometers...............Energy per photon

Ultraviolet A, black light..........UVA...............................400 nm–320 nm.................................3.10–3.94 eV

Near.................................... NUV...............................400 nm–300 nm..................................3.10–4.13 eV

Ultraviolet B,medium wave.....UVB................................320 nm–280 nm.................................3.94–4.43 eV

Middle...................................MUV...............................300 nm–200 nm.................................4.13–6.20 eV

Ultraviolet C, short wave,
or germicidal........................UVC................................280 nm–100 nm.................................4.43–12.4 eV

Far.......................................FUV.................................200 nm–122 nm.................................6.20–10.2 eV

Vacuum................................VUV.................................200 nm–10 nm...................................6.20–124 eV

Extreme................................EUV.................................121 nm–10 nm...................................10.2–124 eV

Hello all.

This is an interesting thread as i am now running a MH throughout flowering to see what happens. I've always heard that MH gives 'better buds' but fewer of them.

I run a 250w Lumitek ballast - the one thing with 250w is that there is very little penetration into the canopy. All the good stuff happens in the first few inches. So, if you can promote shorter stockier growth then you will benefit with, basically, bigger buds. Instead of the buds stretching out along a branch, with the potency dropping away the further from the top it is; having shorter nodes with that bud on them is a much better option.

This consideration is a lot less with the bigger lamps, 400 or 600w, as they go right through the canopy and you can usually be assured that a bud from under a 600w will be 'thick' all the way down.

From the little reference I have, the MH has made the plant start flowering a lot quicker than normal. This is the first time i've grown this cut but talking to the donator has led me to believe that this is definatly the case. He sees flowering start at week 3ish. I'm on week 3 now and i reckon the buds are set and starting to compact and build. Not only that, but the stems are a lot thicker also. Thicker than the donators plants on a 400w HPS.

Keye

mrswoo here you guys are well advanced in this subject wherse the kindergarden?

I would start in the lighting forum and read the stuck topics. You want to start with reading all the safe issue topics. You can also click the knowledge base button on the top right of your screen and do searches in there for basic stuff.

I found this thread to be really helpful. Thanks to everyone that contributed information. It is a great source.

I grew with MH only for quite a while, just under a year running a perpetual crop, I definitely noticed a difference in potency nothing major but in the end the drop in yield was just far too much to swallow, around 30-40 percent!!!!!!!!!!!!!!!!!!!

The HPS lamp is more efficient and the lumens really count

This may bit old, but I felt compelled to share what I've concluded after about 5 years of researching and plant sensors.. I'll keep it short and to the point.... please bear with me as this might clear up a lot of misconceptions... especially with penetration.

First off.. i'd like to talk about wavelength and penetration. Chlorophyll absorbs absorbs reds and blues the best. Wavelengths in the yellow spectrum pass through more easily than red(660nm) and blue. Far-red(730nm) also passes pretty easily. Its extremely important to differentiate reds and far-red as they cause polar opposite phytochrome effects.

Think about this one concept clearly.... The colors that are absorbed the most will logically penetrate the least!!! PENETRATION IS NOT STRENGTH!! penetration means LOW absorbance!!! This doesn't mean you can just have blue and red light though... The reds (630-660nm) and blues get filtered by the first layer, but the yellows penetrate further down. This allows the lower branches to see more yellow and far-red (730nm) than it sees red (660nm) and thus stretches more.

Get me? the better quality light gets absorbed by the top branches while the lower quality light tells the bottom branches to stretch out like an xmas tree until they get the same shade of light as the top branches.

PENETRATION IS THE OPPOSITE OF THE CHLORAPHYL ABSORBANCE CURVE. THE INVERSE OF ABSORBANCE IS TRANSMITTANCE(penetration)!

Phytochromes are the most important sensor governing the shape (localized stretching) of the plant. I have attached an aborbance chart for Pr and Pfr in this post. The different of absorbance of the two at a given wavelength determines %Pfr the branch will converge at. Using that chart, you can approximate the %Pfr each given wavelength will induce. %pfr is essentially color vision for plants. Here are a few examples:

wavelength ----- %Pfr
730nm ----- 0% (only place where Pfr absorbs but Pr doesn't at all! get it? this is key!!)
660nm ----- 85%
630nm ----- 77%
600nm ----- 69%
520nm ----- 50% (Pfr and Pr absorb equally here so %Pfr converges at 50%! get it now?????)

Differences below 500nm are minor and could likely be dismissed. I eyeballed this chart btw.. don't hold me on the percentages. I'm just eyeballing the differences between Pr and Pfr absorbance at those wavelengths because thats what's important.

Now.... Heres where this becomes important.... The stretch rate of a given branch is logarithmically proportional to its local %Pfr!!! I have included a graph here to show how stretch rate is logarithmically proportional. This is important information in determining why certain types of lights cause certain shaped plants!

From my previous post, remember that the best quality light gets absorbed in the first few layers. Those top layers see a high %Pfr. The lower layers lack the higher quality 660nm light but still receive the somewhat useful yellow light. These branches will converge at a lower %Pfr than the top branches thus causing them to stretch out until they find a direct source of 660nm. The stretch graph shows this.

HPS is very high in yellow and this is why it penetrates so well. The reds get absorbed by the top layer while all of its yellow bombards the lower levels more evenly. Its the reason for the xmas tree shape! (i said it again). Yes yellow light causes stretching, but without the contrast of yellow and red, all the branche will think the light is perfect everywhere and thus won't perform shade avoidance on the lower branches. Unless you can truly get high levels of red (630-660nm) to every part of the plant, yellow is essential.

Here's an analogy. Walk into a room only lit with one wavelength (try 660nm) and you'll be color blind! You won't be able to make correct judgments and know how to perform in your environment.

I just made this with paint. This picture demonstrates the first 3 layers of a plant absorbing a full spectrum light source. Its only an approximation so bear with me.

This again shows penetration vs quality. Notice that the more layers the light goes through, the lower %Pfr will converge at. This assumes you start with a full spectrum!!! if you only have a 660nm light source, the entire plant will converge at 85% eventually which i'd say is like lowering interest rates to attract a housing bubble you're telling the lower branches their light source is perfect, when in reality hardly gets any light at all. Having the yellow there gives a contrast of %Pfr between higher and lower layers of the plant. this is one reason I think led grows tend to fail and HPS do so well. Also, the yellow itself allows bottom layers to get some light.

Great stuff! Thanks for that theguyman!

I'll be doing a 3rd diary in the next month or so. It will have some very interesting lighting experiments going on.

I made one more diagram to continue my story. This picture demonstrates the common LED grows we've seen and my analysis.

2nd best read all day!!

im using 2x400HPS and 400MH.

the thickness of my stems is astounding to me. al though the lower branches havent stretched up to the light. so the buds are all tight to the stem.

Awesome, but not ideal. but these were vegged under fluros

it would seem that the idea of vegging in mh is best.

forcing flowering using hps for about 3-4 wks

then either MH til finish for potency or a combination of hps and mh for bulk and potency.

Im goin with the combination of all three and despite the tightness of the growth, It Does Feel Right!!

ef

Cheers

E2A - now im gonna read up on the UVB(reptile lights)

Good read here! always been interested with the different light wavelengths an how they affect plant growth, I've just finished my led veg cabnet, might have to invest in some UV leds Also read up on NextGen ballasts Hortilux bulbs - they look amazing, shame there's no supplier in england, but did a quick search on ebay and theres a US seller who ships to england does the stright 400w NextGen ballast for £161.34 inc postage or the switchable (400W or 600W) ballast for £205 all in and the Hortilux bulbs are between £50-£60 all in, the postage is a fair bit but seems worth it considering the quality of the equipment. The 400W Hortilux Eye Blue produces 80,000 lumens, thats crazy! my 400W MH only produces 55,000, and remember the key to ebay is comunication especially with international sellers. Hope this helps peeps looking for cutting edge grow tech, I'm gonna gets me first indoor grow down before I invest in this sort of kit tho. Out of interest could I use the Hortilux bulbs with my 400W lumatech digi ?

Dont forget a 240vac to 110vac transformer then if it's a U.S. product

NextGen ballasts (I own one) can handle 90V to 260V, although you may need a plug adapter. They are designed to work with generators which usually have fluctuating voltage output.

Just so you know what you're describing is called "photomorphogenesis" in the main and is the science of how light affects plant growth.

In higher plants the main parts of the spectrum that influence growth is as we all know red and blue. The plant has 2 different receptor molecules for it - red is picked up by phytochrome and blue is picked up by cryptochrome.

UV-B is ultimately damaging to plants and the increase in resin production is probably at cost to yield as a stress response, most plants have adaptations to get around excess UVB which tends to be pumping more pigmentation into the epidermis, it's thought that compounds called Brassinosteroids are the receptors for this.

Phytochrome

Comes in 2 flavours which are sensitive to red and far red light, the differing ratios of red to far red are taken by the plant as indicators of total irradiance, the more far red the plant receives in relation to red the more the plant is being shaded and as such far red light influences plant growth in stem elongation as it searches out for more red light - in short the more far red there is it stimulates a shade avoidance growth habit by the plant. Red light is also taken by higher plants as a major stimulus for flowering and bulb formation.

Cryptochrome

Responsible for circadian rhythm in a lot of plants and animals [like a biological clock] cryptochrome being stimulated in cannabis signals to the plant that it is in full sunslight and inhibits it's shade avoidance growth mechanism. Cryptochrome also influences guard cell turgidity and thus stomatal openings which controls gaseous exchange but on this area i'm less knowledgable.

Thanks for that!

(reproduced from Canna UK's site - it's behind a password so I can't provide a (broken) link.

The Influence of Colours on Plants

Light is essential for every plant. Chlorophyll allows plants to convert energy from light into sugars. Does light impact plants in ways other than just supplying them with energy? Do the colours even influence a plant’s growth and development? This article reviews these and other questions.
D. Kroeze, CannaResearch

The primary colours

Researchers have traditionally distinguished seven colours, the colours of the rainbow, red, orange, yellow, green, blue, indigo and violet. We may call these the primary colours. Put together, the primary colours create white light and are visible when a ray of sunshine is split by a prism.

Objects can absorb the colours in light, let them pass through or reflect them. Science tells us that objects themselves possess the colours they do not absorb. Because plants do not absorb green they must themselves be green. There are those who claim that light measurements show that plants themselves emit light particles in the dark and hence actively help create their own colour.

Just as we do, plants sense the light and colours surrounding them – but in a different way!

Red light

Plants are sensitive to red in the light spectrum, a sensitivity that arises from the plant having what is called a red light photoreceptor. The receptor is a blue-green pigment termed a phytochrome present in the cells of a plant. You might think of phytochrome as an eye that only senses red light.

Red light impacts a plant in many ways. Plants that are grown in plenty of red light are often large, but in general are also tall with plenty of branches. If the photoreceptor picks up a large quantity of natural red light, for example in the summer when there’s plenty of natural red light, production of a plant hormone (meta-topolin) is increased. This hormone prevents the chlorophyll in the plant being broken down, so that it stays green in the spring and summer. And that is only beneficial, for it is precisely at this time that the plant needs its chlorophyll to convert energy coming from the sun into sugars.

Red light also influences a plant’s flowering and seed production.

Using the quantity of red compared to the amount of far-red in the light the plant decides whether to start flowering. The flowering period can be extended by exposing the plant during the darker period to red-containing light. It will then take longer before you can harvest which of course you don’t want! This explains why it is unwise to enter the growing area when it’s dark.

The red colour in light also influences flavour because it increases the concentration of special oils in plants. The leaves may have a more bitter taste.

If you want to get seeds from your plants, and you’re looking for possible “female” seed then you need to avoid exposing your plants to excessive red light, because this will cause many seeds to grow, “if applicable”, into male plants. Unless you want it the other way round of course.

Blue light

Plants see blue light as well as red light, using a photoreceptor that is called a cryptochrome. If there is plenty of blue light, as in nature during the autumn and winter, this receptor dampens the operation of a plant hormone called auxin. This hormone is responsible for the plant’s stem growth. Auxin is also responsible for what is referred to as ‘apical dominance’, the phenomenon whereby growth points ensure that buds do not get entwined and create subsidiary branches. This causes the plant to create more side stems when exposed to bluish light and the plant stays a little shorter. This helps us to understand why plants enjoying an early growth phase with bluish light are often squat in appearance with a more robust structure. Experiments with blue light resulted in plants that are wider than usual. This can be explained by reference to the fact that more flowering buds (more branches) could form by reason of diminished apical dominance at the growth point.

Plants use the quantity of blue light to determine how far to open their stomas. The more blue light, the wider they open their stomas, so accelerating their metabolism. High levels of blue light will therefore promote increased metabolism, and by extension accelerate plant growth and development.

Blue light is also responsible for directing leaves and growth points toward the light. Blue light also avoids the multiplication of leaves around the fruits and fertilised plants give more seeds (if applicable to the crop – more female seeds). A shortage of blue light in the spectrum will quickly cause you to lose 20% of your harvest. The optimum red-blue light ratio is 5:1.

Green light and the other colours

Plants are hardly sensitive to green light. As far as we know, they lack receptors for this colour. This is probably the case because in practice plants do not absorb this colour. Plants grown exclusively in green light will be exceedingly weak and rarely grow old.

The clear inference is that plants only sense those colours for which they have specific receptors. Plants are therefore not blind but, to a degree, are colour blind when it comes to other colours. Plants react to orange and yellow light more or less as if it were red and to indigo and violet light as if it were blue.

‘Invisible’ light

The plant on the left is taller because it received
less red light in relation to far-red light. The plant
on the right was exposed to the usual red/far-red
light relationship.

Source: hxxp://www.le.ac.uk


Click to view attachment


Although plants are a trifle colour blind, they can sense colours that are entirely invisible to us. For example, plants can perceive far-red light. Plants often exploit the red/ far-red relationship. A seed uses this relationship to determine germination. Plants also use that relationship to determine the number of other plants in the immediate vicinity. Because plants absorb large amounts of red light whilst reflecting far-red light, there will be less red light in a plant’s immediate vicinity if other plants are in the area too. Seeds will hold off germinating and the plants that are already in place will grow faster in order to emerge above the other plants, so acquiring sufficient light for their photosynthesis.

The fact that far-red light has precisely the contrary effect to that of red light makes it unsuitable as a light for growing. The traditional light bulb is a rich source of far-red light.

Ultra violet light (UV) also influences plants. As with blue light, plants perceive this colour using the cryptochrome photoreceptor. It is unclear whether other photoreceptors can perceive UV light.

If the quantity of UV light is increased, the concentration of a purplish substance called anthocyan goes up. Anthocyans protect plants against UV radiation, but also against micro-organisms trying to get in. Anthocyan build-up can often be seen where there are flaws, such as a lack of oxygen. UV light doesn’t only damage the plant’s DNA and membranes, but immediately disrupts the process of photosynthesis. Therefore an excess of UV light is unhealthy for plants.

Click to view attachment

Light is seeing

As we have seen, light is not just essential for plants when it comes to supplying energy for photosynthesis. By revealing just a small part of the story we have seen how plants use colours to regulate many of their processes. Plants are capable of perceiving those colours that matter to them. Those colours give the plant an indication of its general environment and thus its chances of survival and reproduction. If your plants are to develop, grow and flower well, the composition of the light is at least as important as its quantity. Do not forget that a plant perceives the composition of both direct and indirect light. Indirect light here refers to the light that is reflected onto a plant by other objects such as walls or other plants.

Hi,
I`m only a 3 time grower but I have read a lot.
My first grow was LED whit good yield but airbuds, second was 600w hps better yield.
I did also hear that plants uses mostly red light for the flowering so this time i`m using my hps combined with 90w LED (red and blue light) thaught it might be a good idea ...?
The clones I`m using is from the same mother as my first two grow so it will be fun to watch them, their 2 weeks into flowering and looking goood,its popping out everywere

Freinds of mine have been growing with led s, not bad results.The results of crop size comparisons are not yet confirmed as amount of lights and their hight ., heating and ventilation ., are a new area for experimentation,The benefits of leds are no detectable heat source, cheaper electric bills,Crop size comparisons I think favor led s in cost production comparison Quality seems ok happy growing eric

http://www.ledgrowlightinfo.co.uk/How%20to%20position.html

http://www.ledgrow.eu/diy.html

Lots of info on leds here

I still have yet to see a LED grow as good as an HID grow. And the LEDs are still waaaay expensive.

Forgive me for not checking those links (don't have the time) but the only LEDs that seemed good enough for cannabis seemed to be needing extensive cooling capabilities. Like a running water jacket. Hardly worthy of consideration if that is the case.

Hi there Rand!
Great topic as usual.
Maybe you can help me out.
I intent to use UV lights on my next grow in order to try to replicate the lovelly portuguese sun, i dont stand a chance but you cant blame a man for trying
Anyway i´ve found some cheap UV lamps on the web but i´ve never heard about those...Wood´s lamp???Made out of Wood´s Glass?!
Do you know these ones?Are they any good?
They run at 365nanometers, whatever that means...
Here´s the only mention to it that i could find...

http://en.wikipedia.org/wiki/Wood%27s_lamp

Many thanks

Hi PauloX,

Thanks for the compliments. I'm not a UV expert but I can share what I know. The 365 nanometers is the wavelength of radiation being emitted by those lamps. If you go back and skim these pages, you'll find a graph with the wavelengths of various radiations we are interested in, including visible light.

There are a few different types of UV available (UVA, UVB, etc) but not all of them are of interest to the cannabis grower. Indeed, I would say that UV light is one of the last things you should be concerned about. Getting other things like your environment air, medium and grow room security sorted first, is much more important.

If you are still interested you can check out this link (click here). It's probably the best topic here on how to use UV safely and effectively. UV can cause problems like skin cancer and clouding of the eye lens. The topic link above goes over these concerns and how to mitigate them. It also covers how much UV exposure to give your plants and how to find out what the UV exposure for different locations in the world is. So you can replicate the Portuguese sun. Somewhat.

Good Luck!

Hi Rand!
Thx for the fast reply.
After reading some dozens of threads and articles about the effect of UV lights while growing cannabis indoors i only know that i need to try it myself.
The relation between the trichomes maturation and UV rays.The impact of UV on plants left for seed.
The value of UV rays as fungicide and bactericide, ?is this a word? . The relation between the height of the plant and the UV light available.It all makes sense to me and i guess there´s no better way than the old experimental method

At the moment i got some available running set-ups, mine and from a couple of friends both in england and portugal, and our dream is to discover and maximize the potencial of each individual strain. It´s a long term project but we got all our blessed lifes
In order to maximize our efforts, each one focus in one specific direction, after doing two Sulphur burners and teaching my mates how to do it,i´m now looking into UV lights, what will come next?!?!

Thx again for your help

Ok leaves are green because they reflex green light I know from your diarys rand that you have green flours for night work cause the plants dont in effect see the light. I like the idea of them....but if your growing a purple strain that deveolps purple leaves would this render them ineffectual as purple leaves would absorb some of the green light. ?

Not sure how I missed this thread man. Looks quite enlightening. Pun intended.

I have a quick question though before I read more. I just read that green light has no effect on the plant and that the plant is blind to this spectrum. Yet it said that a plant grown solely in green light will be weak and small. If this is the case, surely it does use that light. Otherwise how would it grow at all, even if it's growth is weak. To me this means that the plant must use green light if it responds to it in any way. Or am I missing something? I'm not saying it's any good for growing with. I'm just wondering if it's true that green light has no effect.

Anything is possible it seems. I did mention at the beginning of this topic (and on a few green light as work light topics) that some plant reactions to certain wavelengths would most likely be strain specific.

So far, every strain I've grown (6-8 but spread over 7 years or so of growing) has not reacted in any noticeable way to green light left on for 12 hours at night

I forgot to mention the obvious. A green light may be giving off more than just green light.

finally read this whole thread (and al the related threads linked to it upto page 3is) last nite but couldnt really think of much to add to it but now I have. having been lookin for a 600w halide bulb but not seen a whole lot til I saw the sunpulse digi halide bulbs and the fact you can choose the colour of the light (degrees kelvin).

If i was adding a 600w halide lamp for a flowering room (for quality of cannabis not luminous efficiency), surely the 6400k would be of most use for that purpose? I think I remember reading plants only absorb light from 3000k-6500k (different sources disclose slightly diferent figures but pretty much the same from what I was reading) and that 6500k is rather blueish. Anybody wish to confirm this? Then about my suspicions about 6500k bein about as far up the kelvin scale I should be wanting to go for quality of crop?

I think im right but thats no guarantee. just lookin at other bulbs an it sais they do a 10,000k, 14,000k and a 20,000k bulb but im unsure of their usefulness if they (plants) dont absorb light from this range(of colour of light...)?

This would be i'd hav to buy a digital ballast but i'd be willing to step forth (and PAY PAY PAY...) and try but only if sure I was buying a quality bit of kit. I remember people slating some, with others rating a particular model (think it was next gen. but not sure) but i'd rather look into it further once the above is confirmed.

edit to say: just looked at lumatek and saw a price of £160 for a 600w one of their digi ballasts from a 'local' shop. is this brand reasonable? can anybody beat the price tho? I dont mind too much if it does what it sais on the tin i.e. 20-30% improved lumin efficiency over standard magnetic coil whatever theyrecalleds (standard halide / hps ballasts) + no heat from ballast etc

Hey weedfiend,

First off, I'm absolute crap when it comes to sussing out kelvin temperatures. Given how competitive the indoor grow shop market is where I live, I just trust (more or less) the sales folk to steer me in the right direction. I've shopped a few indoor grow shops and they are pretty consistent in what they sell. Maybe some day I'll be more bold but for now I like the results with the lamps I'm getting (mostly Hortilux Eye series).

I use Lumateks and Nextgen and both work well, 2 of my Lumateks are well over two years old and working well still. And I push them hard. However this is not the topic for ballasts. If you want that then click here.

Great thread Randalizer a mine of information and experiance.

Here's a OT1 Haze at around 30 inches a month into flower under mh
Click to view attachment

It was a real eye opener as the plant it came from was around 5ft and over 3 months into flowering under hps before any buds appeared.

Finally sussed how to grow sats indoors thanks everyone.

Hi there Rand.
Here´s a little input related with my experiences with the Woods Glass CFLs and the UV rays

These 4 beauties, White Widow from a mum germed from a Nirvava seed in 2007 still going, are in 3,5lts pots with JohnInes3 and tap water My mate swears that the plants become crustier and darker under those black lamps. We are all excited with the smoke quality because my friend reckons that quantity wise it´s gonna be great

I hope the pic works...sorry for the lousy quality

Click to view attachment

Peace and Light in many waves

Nice! I'll have to look those lamps up. Who makes them? Do be sure to give us a smoke report, eh?

Hi Rand.
Here´s some pics of the tanned WhiteWidows

Click to view attachment
Click to view attachment

The smoke test is coming soon

Click to view attachment
Just one more tanned babz

From all reports I have seen, dual spectrum lamps are not as good as single spectrum lamps.

I think now would a good time to mention that I'm not an expert on lighting by any measure. I set up this topic as a way to make it easy for folks to share information on lighting.

Hello people, this looks like a thread that will suit my questions.

Got a 400w ballast. Got a 400w MH and a 400HPS but have been looking at the Grolux Dual Spectrum 400w.

I'd always just done the veg under MH and flowering under HPS.

Q1: This thread makes me think I should do the first two and last one/two weeks of flower under MH. What do people think is the time to swap the bulbs?

Q2: How does a grolux bulb compare? Would it give good results if used from veg right through to harvest?

I've also got a 2x55w sunmate if that helps... what would people do with one sunmate and one 400w ballast? (Bulbs are cheap in the grand scheme of things)

(Sometimes from seed, sometimes clone.)

Cheers people. Look forward to any replies!


EDIT - Ah, quick re-read of the thread and single spectrums are prerfered to the lazy grolux option. Wicked.
So when to change bulbs, and would the sunmate help at any stages?

i think the green light thing is similar to the way outdoor plants don't hermie even when theres street lights and the moon. intensity i reckon a plant receiving the suns strong rays isn't affected by the weak light levels given by a street lamp down the road. plants arent using a lot of green light so its not strong enough to give any bad effects but just like the street lamp over there it may be enough to sustain a plant if its all the plant has ever seen (nothing more intense)

all imo

Two points: I've read that street lights have been known to cause a plant to stop flowering (Jorge Cervantes) and my green cfls are far brighter than any moonlight. and as I have said numerous times, they've been left on over night many many times in the past 3 years.

led's on heaters have been known (well claimed) to hermie plants in flower but its never affected mine , nor have a combination of street lighting/ moon / light coming from the house with my outdoors.

just because your green light is really bright to you doesnt mean it is to the plant , one of the main points to this thread isnt it
maybe im wrong and intensity of the interrupting light has nothing to do with it? maybe the moons light is green ?

ive seen street lights affecting street trees ie localized flowering when there not meant to and in veg when theyre meant to have flowers on!also dont know if its true but i was told once tht plants cant actually see/register green light,dont know if thts true though

im not saying street lights won't affect plants , obviously they will if they are close enough as can a single led.

its the intensity of the light interruption compared to the light the plant receives in its day time period that matters. so after a day of basking in the suns rays the little light from the moon or a street lamp down the road will not be powerfull enough in comparison to bother the plant.

with the green bulb thing .....
maybe that light can be absorbed by leaves but not as easily as the colours we use for growing so in much the same way as the moon thing the little the plant can see is insignificant compared to many watts of hps meaning flowering is not fucked up in any way. that would explain the thing blayzd read about plants growing a little when only given green light?

experiment for rand i reckon!
2 plants (whether from seed or clone) 1 under a green bulb and 1 in total darkness. if canna can't see the green bulb then both plants should sprout and then die around the same time , if green can be seen then that one should live longer.

I have enough experiments thanks. All I know is that extremely bright green lights and several red LED lights (which don't shine directly on the plants, unlike my green lights) have no noticeable effect on my girls.

And I'm so unconcerned about street lights actually.

when lights are on in your flower room how many watts are being used? and what does that equate to in lumens? . how do those green lights and the few led's compare?

im talking about trees that r directly under or next to streetlights ie about a couple of feet away not down the road ,i only notice cause its part of my job to clear these trees for buses etc....ill shut up bout streetlights now

There are three, 1 meter by two meter trays, each has a 600W lamp on a linear over it. Green cfl's are abut 30W. No idea, nor do I care, how many lumens is going on.



Please don't on my account. Just because I don't care, doesn't mean others are not interested.

you don't care about something relevant to a thread you started ?

1800w of hps compared to 30w of light that if is seen by plants its a very small amount , im not supised you've found it has no bad effects.

still the only way to know if green is taken in at all is to try one under green and another in the dark.


KGB, it's cool i know what you meant . it pretty much proves my point about intensity , you seeing it happen on plants close to street light and me seeing it isnt a problem when they are a distance way