Biology lesson.

asf2j said:

so i went down to the board this morning and argued 1st amendment style. they cant keep me off RIU but they can keep me from talking about what im doing at school. Tigghhhtttt

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Seamaiden said:

Damn! Somebody's got a little extra scratch, eh? Put up a thread showing that sled, Humbo.

Now that sounds about right. Good on you for sticking up for your rights and working the system.

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First Question:
I purchased a 400-watt metal halide (MH) lamp. The salesman told me that the lamp could be used for both vegetative and flowering. However, a fellow grower told me that the MH would be a waste of time and a high pressure sodium (HPS) lamp should be used instead. What do you think?

Second Question:
In a single-light garden is it better to use an enhanced spectrum HPS lamp such as a Son Agro 430-watt bulb as opposed to a regular HPS to emit more light in the blue spectrum?

Ed’s Response:
MH lamps contain more blue light and less red light than HPS. HPS lamps produce more total light than MH lamps and more light in the red spectrum, which is used more efficiently than blue light, powering a faster rate of photosynthesis. In addition, read light helps in flowering development.

The only reason to use an MH lamp rather than an HPS is to avoid suspicion that a weird-colored light may arouse. Using metal halide lamps in any stage of growing is a waste of time and money. More total light that is useable by the plant is produced by HPS than MH lamps, so plants grow faster using HPS lamps alone.

The plants don’t need the extra blue light offered by the Son Agro. Enhanced blue light doesn’t increase production. Although plants use blue light for photosynthesis, they use more red light. In rooms with mixed lights (MH and HPS), the plants between the two lights, which were receiving a mixture didn’t perform quite as well as the plants directly under the HPS lamps, but yielded slightly more than those under the MH. You could see the “wave effect”.

The solution to the ballast problem is to replace the MH bulb with an MH-to-HPS conversion lamp. This bulb will fit into your system and is powered by the same ballast as an MH but it emits an HPS spectrum.

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Marijuana plants photosynthesize as long as they receive light as well as water, air, nutrients and suitable temperature. Photosynthesis is the process in which plants use the energy from light (primarily in the blue and red spectrums) to combine carbon dioxide (CO2) from the air and water (H2O) to make sugar while releasing oxygen to the air.
Plants use sugars continuously to fuel metabolic processes (living) as well as for tissue building. The plant combines nitrogen (N) with sugar to make amino acids, the building blocks of proteins. They are the substance of plant tissue. When the light is off, the plant’s metabolic processes, respiration and growth continue.
The marijuana plant can photosynthesize continuously, so it produces the most energy and growth when the light is on continuously. Continuous light does not stress the plant, which reacts somewhat mechanistically. Plants can suffer from the heat emitted by lamps, but will not undergo stress due to continuous lighting.
Plants under an 18/6 light/dark regimen are producing sugar only three quarters of the time. They are thus growing at only 75% of their potential. Leaving the light on continuously will result in bigger plants faster, which leads to higher yields.

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asf2j said:

more people are starting to take notice of this thread, this is both a good and a bad thing.i say that because i have until tomorrow, may 9th, to disassociate myself from this thread completely.


for the first question.
the kind of light(hps/mh/cfl/etc) doesnt matter. at effing all. what you should be concentrating on is the kelvin spectrum (sometimes given in nanometer wavelenghts readings) and the lumen out put. you should also consider the relative heat output from each bulb respectively.

if i may, let me back up my statements. this is definitive, there has been study after study after study regarding specific wavelengths of light that plants absorb. (keep in mind wavelength is the same as Kelvin rating). these "useful" wavelengths are different for every plant(plants in the tropics get more direct sun(less red light) than plants near the poles(more red, due to the angle of the sun's rays))
but anyways, there is a very intuitive reason for why plants use blue and red light.

if you look at the visible light spectrum from left to right, you should realize the colors roy. g. biv. red to the left, green in the middle, and blue to the right. unfortunately i dont have a chalkboard i can draw on to show you what the graph looks like on this forum. but if you can imagine a graph in which amount absorbed is the y axis and wavelength(color) is the x axis. you will see that plants take up a fair amount of the red spectrum, hardly any green, and a fair amount of blue spectrum. the reason why we see a leaf as green is due to the fact that green light is reflected, not absorbed, green light bounces back.

so that was pretty long winded and didnt have much to do with anything, but it is interesting, but is a necessary precursor for the following:
studies have shown that different wavelengths of absorbed light are indeed responsible for the expression of separate hormones, obviously, just like when you got your first pube, your hormone expression was changing and putting your body through the morphological changes associated with puberty. the same in plants. blue light is associated with the summer and IN MARIJUANA associated with vegetative growth. many plants have different genetics that allows for blue light to stimulate flowering. in the fall, you may think of this as when you turned 10, the angle of the sun produces less blue light and a cooler, less energetic red light. the red light sets off a series of second messenger gene cascades( youll have to look that one up, its a whole other topic) that are responsible for proteins and hormones involved in flower formation.

this is the important part to keep in mind, even in nature when cannabis is flowering, it is still absorbing blue light, most notably around noon(obviously), both spectrums are used during flowering, just like vegetating. the most notable difference between the effects of blue and red light is that, IN SEEDLINGS and IMMATURE plants, red light stimulate the plant to stretch, no matter how close the plant is to the source, red light is conducive to shade so the plant grows to get out of the shade. (thats just a neat side note)

what really gets a plant going in the flowering cycle, is not necessarily the type of light, but the cycle of the mysterious TOC protein/hormone oscillation. although many studies show that in mature plants, excessive red light, produces larger flowers mainly due to red light striking appropriate red light phototropins that release more of the "flowering" hormone(s)

so basically, it is the cycle 12/12 that will do it, and really the kind of bulb you choose doesnt mean diddly, so long as you know lumens/color or wavelength or kelvin/keeping the heat with in tolerance.

hope that helps for the first question

and on to the second question.
this ed guy may know a bit, but alot of it sounds like hot smoke, or hot garbage... but he does have a good bit down.

let me start off by saying that i dont know jack about the specs on mh or hps as far as spectrum or lumen.
but i do know that if you are using a single light in your grow, it had better be a mixed spectrum. plants use both blue's and red's and they are responsible for different organic compounds being produced(not just carbs or sugars).

the part about 18/6 only giving you 75% growth. BULLSHIT. ive said it a million times. use my steroid analogy in my first post on this thread. if you dont believe me about TOC oscillation, try you grow on 24/0 for a week and then switch it to 18/6 for a week, and then with another plant for control do the same.

then after that, on your next grow do 18/6 for a week, then 24/0 for a week.

if you cant tell that 18/6 gives huge improvements in growth, your blind.
there are completely different classes or groups of metabolic reactions that happen while a plant is under lights than those that happen when a plant is in the dark, both are necessary for healthy growth... dont believe me, go to any university library, and look for the scientific peer review journals on horticulture.

everything i have said has come from learned scientists with reputable backgrounds and laboratory test. unfortunately im not sighting anyone or anything on RIU b/c i could step into some serious doodoo.

hope that helps.

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Seamaiden said:

and honestly, the idea of giving anything a 24hr. photoperiod seems counterintuitive to me. Where in nature would ANY organism receive that type of photoperiod?

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asf2j said:

yeah the poles, didnt think of that one either. well then you have to think, what kind of vegetaion thrives up there. im pretty sure, cannabis doesnt grow wild, and isnt that 24 hour thing just for like a couple of days, it not for a whole season is it?

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asf2j said:

unfortunately, if i say anything about growing, or condoning the use of marijuana after tomorrow(really tonight at midnight GMT 6), im screwed out of my educational institution.

indeed it makes sense that most aquaria would respond to higher energy wavelength from penetration into the water. i know from my fish nut experience(lmao, i keep koi like no ones business. three 35 year olds and seven 12 year olds. my babies.) that if you go to your local petco you can buy a bulb for every kelvin you can imagine.

emulating nature will most always be the best deal. you make a good point, where in the world does ANY organism receive that much time under the sun? no where.

as far as kelvins(or nm), the best way to do it, if money were no option, and if you could find ALL of the proper bulbs, i would try to find bulbs between 1800-3000, i would go with 5 of these, at 1000 lumen apiece. try to get one 1800, a 2000, a 2500, 2700, 3000. (you get the idea.) you really would see major benefit if you could get all of these spectrums together.
in addition to the lower end of the kelvins, you should also try to find 1000 lumen bulbs between 5000-8000, pick 5 bulbs at increments similar to the other ones i just gave as an example.

ideally you should be shooting for 10,000 to 15,000 total lumens from the mixed spectrum, excluding green light which is about 4000k.

on a super sunny summer day, the sun spits out between 10,000 and 25,000 lumens per sq ft depending on ozone, cloud coverage, smog, and a few others things.

more lumens, will make your plants produce more, just as long as the heat is kept in check.

so a recap, mix the spectrums as much as possible, exclude green light~3500k-4500k, shoot for 10,000 lumen or more, if you can. you will still get growth with less lumen, just ultra, ultra slow.

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Seamaiden said:

Jeez.. duh. And I'm not even high! What else can I blame it on?

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asf2j said:

hhahaa, email your awesome

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