Water - The Basics

Mad Hamish

Well-Known Member
Hi All!


I decided to put this basic little guide together on water. Our plants are made up of mostly water, so little wonder that it affects them so deeply, get it right and they thrive, get it wrong and it all goes downhill very fast indeed. I recently ran into some unexpected problems, I became complacent about this one single part, and it kicked my ass lol...


WATER IS LIFE


So let's start at the beginning: Not all water is equal. Unfortunately it can vary vastly in many regards, a spring, a tap, rain water, not only are they different from each other, but springs vary vastly, I've seen different readings on tap water only a few blocks apart in the same town, I've tested rain water with a pH as low as 5.8 and as high as 8.5, and that was at only MY HOUSE (depending on the wind it comes in on mostly). So the most important part is to know your own water supply!


Some jargon busting before I continue:


pH - A measure of the acidity or basicity of an aqueous solution -


https://en.wikipedia.org/wiki/PH


EC - Electrolytic Conductivity is a measure of the ability of an electrolyte solution to conduct electricity, measured in Siemens ( 1 EC = 1 mS/cm)


We use it to measure the ionic content of our 'solution' (water). In ganja terms, we use it to tell how much food we've dissolved into our water. EC is directly linked, for our purposes at least, to TDS, up next...


http://en.wikipedia.org/wiki/Conductivity_(electrolytic)


TDS - Total Dissolved Solids is a measure of the combined content of all inorganic and organic substances contained in a liquid in: molecular, ionized or micro-granular


So in short, it's a measure of EVERYTHING. Once again, for our purposes we use it to tell us how much food we have added to the water, basically.


As you can see it is by far more thorough but there's a little catch to it, the most accurate way to measure it is called gravimetry which pretty much means you evaporate all the solvent/liquid (water) and measure the stuff that stays left behind.


So how it is mostly done is, you guessed it, measuring electrolytic conductivity (EC). Lab comparisons show that measuring conductivity can give you an approximation of real TDS, within 10 percent accuracy.


You can see it measured in mg/l or PPM, which is Parts Per Million. PPM is a quantity per quantity notation and as such is PURE NUMBERS with NO ASSOCIATED UNITS OF MEASUREMENT.


If you intend on working with PPM as many, many people do, sharpen your math skills lol...


So with that out he way let's get busy...


You will see references to different kinds of water, especially when it comes to feeding. A quick list of the most commonly used, and going by the US's EPA definitions here:


Purified Water - Distillation, Reverse Osmosis - EC of 0 or close to, under 100 MICRO Siemens.


Filtered Water (CLEAN Carbon Filters) - EC between 100 and 200 MICRO Siemens. (Between .1 and .2 EC) This means that there are some traces of minerals in the water. Not too much, but already enough to affect the balance in nutrient solutions a little.


Hard Water - EC between 200 and 400 MICRO siemens (Between.2 and .4 EC).
Now there is starting to be a real contribution to our water. Mostly Mg and Ca (USUALLY), but not really enough to cause any kind of excess when used with well formulated nutrients. Matter of fact, it helps out coco growers quite a bit seeing as it boosts what the coco holds back.


Tap Water- Average tap water has an EC of between .4 and .6, or 400 to 600 MICRO Simemens.
Right here it gets downright tricky at times. Every grow-guide, every forum you can go looking on, you will find it STRESSED as a matter of PARAMOUNT importance: You need to know what is in there. You NEED to know what is inside the stuff coming out your tap. In some areas having your water tested is a free service, in others it is not. But no matter what the cost, it WILL be worth every cent of your money. ANY SITUATION CAN BE COMPENSATED FOR. On these forums alone there are a LOT of very experienced people that will gladly help you formulate your feeding program in accordance with your water. They can NOT do that if you are unable to show them what is already in there. YOU NEED TO KNOW.


If the water you intend to use has an EC higher than that - - - Time to invest in some good filters or consider RO...


It starts becoming questionable if you want to DRINK it, and in that case your plants won't want to either!


OK, so now you know your water contents, ready to go, right? WRONG.


I have seen this question many many many times: HOW IMPORTANT IS pH?


I will answer that question with another question: How does this example of pH lockout look to you? Essential or not, you tell me! Thumbnail, bottom of page...




To be brief about it: Everything you see around you is some kind of chemical process. Chemistry really is what makes life work. And the pH of your solution will affect the processes happening in the soil, plant, reservoir, it affects EVERYTHING.


To complicate things, there is no universal 'correct' pH. What are you growing in, Coco? Soil? Hydroton? DWC? Whichever one is your choice, I urge you to spend the TINY bit of time it is going to take you to fix it to where it should be.


There is much great info on the topic around. From buffering your medium to making your own pH adjusters, it's all here on RIU. I'm not going to cover that, that's YOUR reading to do lol...


Do I need to buy an expensive meter already?! No, you don't. But I do suggest you save for one if cash is tight, or if you enjoy the hobby of growing reefer. They save a lot of effort, especially when the time comes to make fine adjustments. They last pretty long too. But it's not the only way...


Using Litmus Paper Correctly: Litmus paper is cheap and easily found in chemists/drug stores. I prefer litmus paper to drops of liquid in vials. Matter of fact, I can't live without my litmus paper anymore after my meter gave in on me last week. They saved my ass bigtime.


Many guys complain that they don't get consistent readings and have other problems with the papers. So here's a little step-by-step to keep it as on par as possible:


First, make sure you're holding them with something DRY and CLEAN. I don't recommend pinching them between your fingers, you will affect the results if the moisture runs up the paper and onto your fingers. I like using a set of tweezers.


Second - Don't make them WET. Don't dip the whole thing into your solution and expect happy results, the dye will leave the paper and run all over the place, concentrating here, thinning out there. I use a small 1ml pipette, squeeze out HALF a drop, and touch that to the paper. It will spread out into a nice even colour. So extract a little water into your CLEAN pipette or syringe or whatever, and drop onto the paper.


For testing run-off, lift the pot and you will usually find a little half-drop dangling by one of the holes or off a root, touch the paper to that BRIEFLY and take your measurement.


Never come back and look at the paper later they WILL have gone a lot darker. The best reading is taken in under a minute, but longer than 30 seconds.


If you do end up with dye running around - Take a fresh reading.



OK SO I'VE GOT MY pH SPOT ON AND I KNOW MY WATER, READY TO ROCK 'N ROLL NOW?!


Yeah , I guess so. Ready to start, but still a heap of stuff to watch out for. I'm a touch tired of typing now, so I'll come back later (thins week or MONTH lol) and start covering water MAINTENANCE, and my favourite: THERE'S STUFF ALIVE IN THERE!.. Which, for many of us at some point, there will be lol... The coolest part is adding living stuff ON PURPOSE ;)


Right, I've got some clean water in a bong I need to go pollute with some resin, see you all
 

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Ty very much for the info! Best times to water?
I usually water during the first couple hours that lights come on. It's not the best idea to water towards the end/during the dark cycle as plants dont use any water during the dark hours.
 
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