Survival UK Forums

Light science

its probably got a proper name but if it has i dont know it. (probably photonics or something weird)
it is covered under the section of science known as physics.
we dont need to go into it too far or this will just get silly.
were not going to bother going into the complications of particles and photons and all the stuff most will never need.

most of you think of light as just something we see by.
it comes from the sun, or an electric light.
some will know it has UV particles etc that bombard our skin, but were not going to cover that either its not necessary
we all know we should wear sun cream by now.(maybe we should look into a simple homemade alternative though)

Light is made up of all colours and it affects all living things.
we think of it as white but it is not, all colours are present we see this as it splits when passing through a prism.
some of you will know that certain colours of light affect out night vision differently etc.

why is this important ?

light regulates all living things. from plants to animals.
light is how we know the seasons other than through the obvious means of cold wet windy snow etc.
some people suffer with winter blues if they dont get enough light, but thats not the only way that it affects us and the world around us.

Learning to manipulate light can bring many benefits.

if we extend the amount of hours a plant gets we can extend its vegetitive state and give us a longer growing period.
by lowering it we can make it flower (depending on the plant) giving us vegetables out of season.

but just altering the amount of light isnt enough. you need to alter the colour too.

this can be done with simple filters.

summer light has a different colour to it than autumn light and so does winter and spring.
the three colours that affect plants the most are red blue and orange. (HPS sodium bulbs are good for orange and red , metal halides are very strong in the blues))
flurescents are best avoided unless for cuttings or seedlings.

if your gonna extend a plants hours of light you need to know what colour the light is meant to be or the affect wont be desirable.
it could keep it in a prolonged growth period , but the growth would be too slow and pointless giving no benefit or the plant would become weak etc.

ive only touched the surface of this subject basically because im far from qualified to teach people about light.
I havent even touched light intensity which is just as important to plants.
My intention here is only to make you aware of a subject that isnt as straight forward as a lot of us think.
Light is a subject that is a lot easier to study whilst you have internet access.
than to try learning about after the SHTF when theres only 1 or 2 books on the subject dotted around the world.

Hydroponics can be a fascinating hobby , give it a try , its the hobby that rewards you with food.
and its always good to have food that shouldnt be capable of growing in england especially in the middle of november.

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to get a good understanding of both light and water there is an excellent book called Golden harvest
and its sister book called green harvest by G. Mayfield .
Its all relating to the illegal indoor growing of an illegal plant ( we all know which one)
but the information in there regarding light and water is the same for all plants.
only the parameters change.

Its only the basics, but its enough for what most people would ever require . its certainly the best book ever written on the subject of light and water from a gardeners point of view.
It even touches on organic hydroponics.
just don't go planting anything illegal.

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its all just science to me .

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bet you didn't know that insufficient light and wrong ph can turn some plants hermaphrodite.
wonder if its the same with humans lol

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and strong uv light will kill every single micro organism in water if its passed through. its why its sometimes in pond filters.

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not all, but all the ones that matter. and the rest of your filter didn't remove.

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the books I mentioned are pretty much classed worldwide as the illegal growers bible . it even shows you stealth methods of growing outdoors.
if its not in those two books then you don't really need to know it. learning more is just 4 fun.

Organic hydro? Tempting, im stuck with this stinky gmo stuff

its not as hard is it sounds. those books show you how to make the basic feeds using cheap components.
the rest you would work out yourself by the time you've finished the book.

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basically if you get the NPK right and the TDS but the ph is wrong you use a little vinegar to alter it and away you go. but you need to understand water chemistry first .
its best for most to just use traditional cheap stuff. ammonium nitrate , phosphor , iron etc
most people don't really want to go too deeply into water chemistry.

growing organic hydroponics comes with a lot of small complications.
plants need different nutrients when flowering , more phosphor and less nitrogen.
and when growing they usually opposite , you always need to know the plants requirements.
getting organic feeds to hold their ph stable is difficult if you don't understand kh

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and a feed at the wrong ph wont do the plant any good even if the nutrients are right, because it cant absorb them and process them properly.

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in liquid feeds the tds and Kh is important as you cant hold a stable ph without a high kh.
but if you add organics (nutrients) to the feed its tds gos up and its kh will come down making the ph remain stable.
what really happened was the organics were acidic and tried to lower the ph , but the Kh acts as a buffer and brings the ph back up but lowers itself.
you need to keep your feed at a ph that is suitable for the plant.
this can be difficult to do in some softer water areas so you would need to then add calcium carbonate . this would raise the ph back up if it has dropped too far.

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its really all about knowing your water if you want to grow successfully with organic hydroponics.

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mr G Mayfield can explain it in better terms.
ive probably just made it sound a lot more complicated than it is.

yay i can chuck some info in here too! also you might wanna define some terms before using them so other people know what you mean, things like NPK is the nitrogen, phosphorous and potassium etc. i recognise most abbreviations you mention, although things like kh and tds?

Ok crash course on light physics time

Light comes in lots of different wavelengths, anything from a billionth of a metre to thousands of metres (just imagine it as how high the wave is!) the smaller the wave, the quicker it goes up and down (oscillates) and also vice versa.

Light is just electromagnetic radiation, this includes everything from UV, infrared, microwaves, visible light and even gamma radiation!...they are all just photons (bits of light) vibrating at different speeds and sizes. (for instance red light is bigger than blue light is)

when you see the colour of something, what you are actually seeing is the reflected light, so if something is green it is reflecting green light, but absorbing the other colours of light, if a plant was absorbing all the available light they would appear black, and if they were reflecting it all they would be white.


PH time.

PH is the activity of hydrogen ions, what this means is the amount of hydrogen atoms that are missing an electron, as the electron is the negative bit of the atom a hydrogen ion would be positive. the hydrogen ion wants to be a normal atom, so it wants to steal some electrons from something else, which is why it is reactive!....what an acid does is it "donates" a hydrogen ion that ion then steals itself an electron, and bonds either to another molecule or to another hydrogen atom, making Hydrogen gas (which is highly flammable) and some other stuff, the stronger the acid, the more hydrogen ions it has to donate.

an alkali will accept a hydrogen ion which is why when reacting an alkali with an acid you get water and a few traces of other molecules. The stronger the alkali the more hydrogen ion's it will accept.


so when your balancing pH your just tweaking these things to a point of equilibrium wherever you need it. (for reference aforementioned illegal plant likes a ph of roughly 5.6-6.2 pH, though this varies strain to strain).....so if pH is at 7 (pure water) and you want it to be slightly lower, say 5, add something acidic to the water and it'll get lower, likewise if you need a pH higher than 7 you need to add some alkali (its technically called a base though, an alkali is a base dissolved in water)....and if you ever overshoot your needed pH, just add the opposite to bring it back

Hope none of that was too technical, i'm gonna stop now before i really go on a proper lengthy discussion on it all xD

lol dude I tried not to go into too much depth , just enough to explain the importance of understanding it.

its good to see im not the only Geek in the village

loved the bit on ph, was considering that myself in my post on water science. but decided against it as it would have put off the techno phobes.

thanks loads for your input Hrusai, greatly appreciated.
its good to know atleast one person didn't read it and just get confused.

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Kh is just carbonate hardness (dissolved salts)
tds is total dissolved solids ( it includes the dissolved salts and dissolved organics)

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carbonate hardness is a buffer that trys to keep the ph stable. the higher the kh the more stable the ph
if you add acid to high kh water it will lower the ph but the ph will just rise again, and the kh will lower.

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until the kh becomes too low to act as a buffer and then the ph will start to remain where you altered it too.
this can require a hell of a lot of acid if the waters kh was very high.

lol woops xD hey ho, if it teaches 1 person 1 thing im happy

aye, i think understanding pH its necessary to go into a bit more detail, its all very well and good to know how something works, but understanding it will make it alot easier to work with and allow more flexibility in knowledge etc.

heh, im a massive geek dude and proud of it! read new scientist every week and lots of other stuff on the internet besides


thanks for clarifying those terms for me mate! never come across them before, though i've never researched water specifically in any depth before.

presumably then as tds is all dissolved solids this would be the main measurement to determine water hardness? giving rise to the so called soft and hard water you get in different areas of the country....actually that would make alot of sense as having more dissolved solids would make the water feel different and cause harder water to be more abrasive and therefore better for cleaning, and the by-product of having more minerals and such like making it simultaneously more healthy to drink then.

ok thinking out loud now lol

nah kh or gh is water hardness , mainly the kh that's the one to watch
organic solids lower ph and hardness. (rotting plant matter is acidic)

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gh just means general hardness but its not too important. kh is the important one really

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and yup im a bit of a geek myself. im a sucker for a science paper.
its like an addiction. as long as im filling my head with something I don't care if its nutrinos.
quasars . or bromiliads.

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bromeliad is only a flower so don't bother googling it. and I know you know what the other two were lol

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although it is an amazing flower, a tiny frog lives in it at the top of the tree canopy. but that's a whole different story.

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the flower supllies the frog food water and shelter. the frog provides the flower its waste (fertiliser)
its a symbiotic relationship.

only a flower, only a flower! flowers are bloody interesting xD....waaa a mini frog flower, ok thats today's topic of choice xD....aha its a symbiote, i love symbiotes xD its the most literal metaphor for the phrase "ones man trash is another man's treasure"....also i think that humans must learn to be proper symbiotes too, gotta give back to nature after all!

oh ok so gh would be kh plus something else then?...im learning loads today

heh neutrino's are cool, from the sun alone every single person on earth is permeated by something ridiculous like 650 trillion neutrino's a second xD

if I add acid to hard water the kh (Buffer) will lower and the ph will stay the same.
this will also alter the gh but by a different amount.
you don't really need the gh its a measurement that your unlikely to need.
once iv added a lot of acid the kh buffer will have gone resulting in soft water.
but it isn't really its still there its because the acids have dissolved solids too so the TDS gos up
its now more of a chemical soup than water.

sadly water chemistry although it should be simple and smaller than all the other science it isn't.
out of curiosity goodle water chemistry and find some scientific papers youl see what I mean
Its shocking just how much there is to water.
but it does cover most of the planet and were mostly water too. of course it had to be amazing lol

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as for the bromeliad its a very amazing flower. I said just a flower because most people don't see the science in nature. to them its all just trees and flowers.

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too me the whole world is just science.

some call it god , I call it science.
some call it nature , I call it science.
some call it science, I call it god lmao

oh ok i think i understand it now thanks for taking the time to clarify everything for me properly

water sure is amazing, i've read a fair few interesting snippets here and there, but i think i'll start looking into it properly now, after all its the lifeblood of our, and (almost) all other, species.

a man after my own heart! im very much the same, the universe and everything in it is the greatest miracle of all, and science is the key to that miracle, which is why i love science so much plus i just got one of those minds that likes understanding how stuff works and why