Does pH change over time?

qwizoking

Well-Known Member
"The last place to listen for advice is on this forum most of the time."
Probly thanks to ppl like you

So what's your definition of a stable soil? And what's your water like? Your soil mix and water probly work nicely together....to put it on the internet that, that will be the case for everyone leads to issues

Yea I've been growing over 10 years too so what.. I know ph is important even though I don't test the ph I still alter it or yea you will get deficiencies..I have to lower my ph slightly or I will get banding on my leaves etc... and I grow landrace sativas, you think you can't swing the ph in 8months? Lol what about a perlite hempy what do you do then? Lol..it has effect when the water hits the dirt
 

Jeffdogg

Well-Known Member
Talk to any experienced grower and they will tell you that one of the most important features of their grow is the ability to control pH. pH (which, as most people are unaware, stands for "potential Hydrogen") is of paramount importance to any hydroponic/soil grow operation because it affects the way that nutrients are absorbed into your plants. Many growers have long had an adversarial relationship with their nutrient solution's pH, but recent advances in nutrient technologies have made pH much more easily balanced within the nutrient reservoir, without the need of buffer solutions like pH up (an alkaline solution) or pH down (an acidic solution). Here is the lowdown on pH, how it affects your plants, and how you can keep it in that "sweet spot" that plants love.
Why pH Matters:
All green-leaved plants can survive just fine with a pH between 4.0 and 7.0. Basically, because the plants are made of relatively weak acids, they enjoy an environment that is also on the acidic side. However, when you are growing hydroponically, the nutrient solution that you provide to them is their life force, and nutrients will not be absorbed properly without the solution composed of the correct pH.

While the optimum pH for plant uptake may vary from one mineral to another, experts have determined that the optimum range for most of them is between 5.5 and 5.8 (DWC) and between 6.5 and 7.0 for soil, though many growers will argue that anything up to the 6.2 range is perfectly fine for hydroponics.
Minerals like Manganese (Mn), Copper (Cu), Zinc (Zn), and the especially critical Iron (Fe) have reduced absorption rates at a higher pH, while Phosphorus (P), Potassium (K), Calcium (Ca), and Magnesium (Mg) have issues being absorbed at a lower rate. This doesn't mean that no nutrients are absorbed at higher or lower pH levels, but why waste valuable nutrients because your roots essentially don't know that they are there?
Controlling pH
There are a variety of tricks to keep your pH balanced. Firstly, for God's sake, make sure you have a meter, and a good one. My advice to growers is that nutrients, meters, and lights are not the places to save money. Spend some dough on a great tri-meter (pH, ppm, and temperature), and you will have the best chance of knowing what is happening in your reservoir.
Also, invest in some simple aerators to keep the nutrient solution in your reservoir constantly circulating; this will add oxygen to your solution (which makes roots happy) and make sure that all of your nutrients are evenly distributed. Aerators are inexpensive and can be purchased anywhere from hydro stores to pet stores, and even Target or Wal-Mart.
To keep pH within that optimum range, growers have traditionally had to rely on buffer solutions, like pH up and down. While relatively inexpensive and incredibly effective, these buffers add unnecessary particulates to your reservoir, often causing your ppm meter to register a higher number than it would if it were only measuring your nutes (like it should). They are also extremely caustic and burn like hell when they come in contact with skin, especially both at once.

One trick of the trade that is lesser known and less commonly used (though can be effective if you know what you are doing) is to add excess levels of Phosphorus (P) to your reservoir. Because of the way that it interacts with the other nutes, it will work to keep your pH at an optimum level (for a while). The downside of this technique is that as you use the nutrient solution in your reservoir to water your plants, and it recycles back into the reservoir in a never-ending cycle, your plants will uptake not only the nutrients that you mixed for them, they will absorb that extra Phosphorus as well. So, when using this technique, the efficiency drops as you water your plants – nothing will be as accurate as a brand-new, freshly mixed reservoir.
Changing the Game
While the info here will allow you to have a successful grow and harvest (providing you do everything else correctly), it takes time, effort, and constant monitoring to keep pH at an acceptable level to your plants. Your little green buddies will absorb nutrients at different levels during different parts of their lifespan (veg vs. flowering), so your pH will be constantly changing, and not always in the same direction. It takes a dedicated grower (or an automated system) to stay on top of this.
 

plaguedog

Active Member
Here is why I asked you guys if you knew what Alkalinity is. And why it is so important to know

What Is Alkalinity?


Alkalinity is a total measure of the substances in water that have “acid-neutralizing” ability. You can think of alkalinity as the buffering capacity of water and such as how much lime is in the water. Alkalinity is attributed mostly to the amount of calcium and magnesium carbonates and bicarbonates, which are major components of limestone that is dissolved in that solution. Alkalinity should not be confused with pH. While this pH of a solution is the concentration of hydrogen ions in it and measures the strength of an acid or a base, the alkalinity reflects the power of the solution to react with acid and keep the solution pH from changing. The alkalinity, then, indicates how well a solution is buffered. While alkalinity sounds very much like alkaline, keep in mind that they are not the same thing; alkaline is a term applied to solutions with a pH higher than 7.0.
The alkalinity level has far-reaching implications because high alkalinity has a strong effect on the substrate pH. Of two water sources, one with a pH of 9.0 and alkalinity of 50, and the other with a pH of 7.0 and alkalinity of 300, the former will raise substrate pH very little, while the latter will cause a much higher raise in the substrate pH. In general, water alkalinity is more important in determining effects on substrate pH than the actual pH of water.
Because bicarbonates and carbonates and are the major components of water alkalinity, most laboratories equate Total Carbonates [TC = carbonates (CO[SUB]3[/SUB][SUP]2-[/SUP]) plus bicarbonates (HCO[SUB]3[/SUB]‾)] with alkalinity. Other laboratories assume that bicarbonates are the sole contributors to alkalinity.
Alkalinity may be expressed as parts per million (ppm), milligrams per liter (mg/L), or milliequivalents per liter (meq/L) of equivalent calcium bicarbonate or carbonate alone. Various sources prefer to use one or other of these units, and unless you are familiar with the conversion factors, it could be rather confusing. The following is the conversion from one unit of measurement into another:
50 ppm CaCO[SUB]3[/SUB] = 50 mg/L CaCO[SUB]3[/SUB] = 1 meq/L CaCO[SUB]3[/SUB] = 61 ppm HCO[SUB]3[/SUB]- = 61 mg/L HCO[SUB]3[/SUB]- = 1 meq/L HCO[SUB]3[/SUB]-
In the aquifer, water comes in contact with the rocks and dissolves some of the component minerals. The longer the duration of contact, the more minerals are dissolved (this is why after prolonged periods of drought the alkalinity of a well may rise and the opposite may occur during rainy periods). When the calcium and magnesium carbonates and the calcium and magnesium bicarbonates are dissolved, they dissociate into calcium (Ca), magnesium (Mg), carbonate, and bicarbonate ions:
Ca[SUP]2+[/SUP] + Mg[SUP]2+[/SUP] + HCO[SUB]3[/SUB]‾ + CO[SUB]3[/SUB][SUP]2-[/SUP]
The substrate pH rises because the carbonate and bicarbonate ions react with the substrate acidity (H[SUP]+[/SUP]) to form carbonic acid, which in turn converts to water and carbon dioxide.
HCO[SUP]3[/SUP]‾ + H[SUP]+[/SUP] → H[SUB]2[/SUB]CO[SUB]3[/SUB] →_H[SUB]2[/SUB]O + CO[SUB]2[/SUB], and CO[SUB]3[/SUB][SUP]2[/SUP]- + 2H[SUP]+[/SUP] →
H[SUB]2[/SUB]CO[SUB]3[/SUB] → H[SUB]2[/SUB]O + CO[SUB]2[/SUB]
In these reactions, the acidity (H[SUP]+[/SUP]) and the carbonates and bicarbonates are consumed. The loss of hydrogen ions in the substrate results in a higher pH level. This is the mechanism through which alkalinity in the water increases substrate pH.

source: Argo, W.R., and P.R. Fischer. 2002. Understanding pH Management for container-grown crops. Meister Publishing. pp. 64.


Why do I bring this up? Because almost all MUNICIPAL TAP water sources are not even close to having a high alkalinity reading, NO MATTER WHAT THE pH of thre water is.
 

FuckJeffGoldbloom

Well-Known Member
[h=2]Definition of definition (n)[/h]Bing Dictionary

  • def·i·ni·tion
  • [ dèffə nísh'n ]


  • meaning of word: a brief precise statement of what a word or expression means, e.g. in a dictionary
  • act of defining word: the act or process of defining what a word or expression means, e.g. in writing a dictionary
  • clarification: the act of describing or stating something clearly and unambiguously
Synonyms: meaning · description · explanation · classification · characterization




OHHH lets stop, Peace love happiness
 

plaguedog

Active Member
When it comes to managing the pH of a substrate, the alkalinity concentration has a much greater effect than does water pH. Alkalinity (calcium bicarbonate, magnesium bicarbonate, and sodium bicarbonate) and limestone (calcium and magnesium carbonate) react very similarly when added to a substrate. And just like too much limestone, the use of irrigation water containing high levels of alkalinity can cause the pH of the substrate to increase above acceptable levels for healthy plant growth.

[..]

Alkalinity is a measure of how much acid it takes to lower the pH below a certain level, also called \ acid-buffering capacity. Alkalinity is usually measured with a test kit where dilute acid is added until a color change occurs at a specific pH. Alkalinity is not a specific ion, but rather includes the concentration of several ions that affect acid-buffering capacity. Under most conditions, the ions that have the greatest effect on alkalinity are bicarbonates like calcium, magnesium, or sodium bicarbonate and, to a lesser extent, carbonates like calcium or sodium. Several other ions including hydroxides, phosphates, ammonium, silicates, sulfides, borates, and arsenate also can contribute to alkalinity, but their concentration is usually so low that they can be ignored.

SOURCE:Bill Argo, Ph.D. Blackmore Company, Tel: 800-874-8660, Int’l 734-483-8661, E-mail: [email protected]
Originally printed in 2003 in the Journal of the International Phalaenopsis Alliance, Vol. 13 (1).


I really like your pictures though. They apply to the mentality of RIU.
 

Adjorr

Well-Known Member
honestly man im not reading ur whole posts at this point. bottom line people should be aware of the ph of their growing medium wheter they check it everytime or not you need to know what your growing with
 

plaguedog

Active Member
honestly man im not reading ur whole posts at this point. bottom line people should be aware of the ph of their growing medium wheter they check it everytime or not you need to know what your growing with
Of course you're not, why would you actually want to learn anything? Bottomline, by not knowing the ALKALINITY of your watering source is more detrimental to your plants then anything you think you know.

By the way, you're the one that asked for sources, and now since they don't follow pot parroting forum myths you don;t want to read them? Your loss, noob.

Bottom line is this:Between 40 and 120 ppm of Total Alkalinity is generally recommended to maintain a stable medium pH over time. Lower TA tends to lead to low pH problems and high TA leads can lead to high pH problems.
 

Jeffdogg

Well-Known Member
Including your mentality, you just dont get it. Your keep forcing what you believe in to other people who have a totally different belief set. Your not gonna sway a shaolin monk into Christianity. Just give it up man its not worth it at the end of the day...


Life's too damn short to fight battles that are pointless, listen to this and call it a day with this thread like im hoping some of the others do as well.. :)
[video=youtube;XIycEe59Auc]http://www.youtube.com/watch?v=XIycEe59Auc[/video]
 

Adjorr

Well-Known Member
Of course you're not, why would you actually want to learn anything? Bottomline, by not knowing the ALKALINITY of your watering source is more detrimental to your plants then anything you think you know.

By the way, you're the one that asked for sources, and now since they don't follow pot parroting forum myths you don;t want to read them? Your loss, noob.
heres the thing everything ur posting is just backing up our points about how important having the right ph is, we already know this so why relearn it. the issue u keep arguing is that people shouldn't check there ph, and then u post information about how important ph is and how important it is to know the ph of ur medium and water

so why are u so against people ph'ing there water!
 

plaguedog

Active Member
heres the thing everything ur posting is just backing up our points about how important having the right ph is, we already know this so why relearn it. the issue u keep arguing is that people shouldn't check there ph, and then u post information about how important ph is and how important it is to know the ph of ur medium and water

so why are u so against people ph'ing there water!
You don't GET IT. The ALKALINITY of your water source has more of a direct impact on your growing medium then the just the pH of the water alone. Most tap water falls between the numbers I have provided REGARDLESS OF THE pH of the water.

For the record, the water I use has a pH of 7.74
Alkalinity (CaCO3, mg/l):105

When I mix my fertilizer it falls all the way down to a pH of 5.2 (Different forms of Nitrogen effect the pH levels of water, but they hardly interfere with the plants ability to uptake the micros) I never use pH up and have never had a pH substrate/medium problem because the alkalinity of my water doesn't effect my substrate AT ALL over the time is takes to grow cannabis.

I said I don't pH my water, but I did in the past, until I leaned that it didn't even matter. What I do have is a grow journal that I have made notes in over the past 10+ years though so I could pull the numbers when I needed to.

More plant problems come from the basics, heat or moisture stress then anything else I have seen.

And I am NOT against anything here, just trying to explain to you that pH'ing your nutrient solution while growing in a soil/soiless medium like a peat based mix has little to no effect on the substrate that you are using! Unless your waters alkalinity is off the charts of acceptable municipal water supplies. That is why I asked you what your source was. (Tap?? Well??)
 

Nullis

Moderator
Fortunately we don't have to get quite that complicated here.

My answer speaking from the perspective of a living organic soil grower is that sure, pH "matters"; but it doesn't really matter to me. It matters to the plant and the organisms living in the soil and they are going to influence pH to have it their way. In soil there is no homogenous pH you can stick a little probe into and 'measure', or at least there shouldn't be. Whatever number you get may or may not be somewhere within a range of which you don't exactly know the boundary.

Anybody who knows a little bit about how plants absorb nutrients knows that plants are influencing the pH of the soil solution within the rhizosphere, where the root meets the soil, and plants are directly influencing soil pH just by taking in nutrients. They exchange H+ for other cations and bicarbonate (HCO3-) for other anions, for example. They may exude compounds to liberate ions locked up in compounds in the soil. Organisms will produce bio-slime films around them to protect themselves and their colonies, for example bacteria generally produce an alkaline bio-slime. And if you want to get real fucking technical, the type of N you use can lead to pH changes over time. Ammonium nitrogen will acidify soil over time. Humic\fulvic and organic acids chelate metals the plant might otherwise have difficulty absorbing.

If you use sphagnum-based soil or potting mix and know a little bit about cation exchange capacity then you might understand why the pH can plummet at some point and if you're not watching it you're going to have problems. Sphagnum peat by itself has a low pH (4-5), which is why they lime it. Usually they don't add enough lime to support Cannabis long term, however. The reserve acidity of the peat reacts with the calcium carbonate or calcium magnesium carbonate mixed into the lime; forming water, carbon dioxide gas and liberating Ca\Mg cations, which are adsorbed by the [negatively charged] particles on the peat. Over time, the plant takes in the Ca++ or Mg++ and H+ cations again saturate the peat: so it reverts to acidity.

This is why many "soil" growers or people who use potting mix add garden\dolomitic limestone to the mix before transplanting into it, especially for the final transplant before bloom. Another consideration, though, is what you are using as a water source. If you are using hard tap\well water then lime may well be the cause, and hence you have a water which has a higher than typical pH because you've actually already got lime (or calcium bicarbonate in this case) dissolved in the water.

so riddle me this then, theres been 3 times I ddint ph my water throughout the last year based on advice from people like u not to check my waters ph since im using soil. everytime its resulted in a nutrient issue that ive had to fix and has set my plants back.
so tell me again not to ph my water please, I just love reading about it. and please post all these scientific facts and refrences you keep talking about because in my real world experience not checking ur ph leads directly to problems
Riddle yourself on this one. I wouldn't recommend to anybody who has been using pH Up and hasn't prepared a mix with adequate lime to just stop doing what they are doing, although maybe they could cut back on the Up because they are using more than they really need. IMO you're kind of battling against the soil\plant because it really is trying to do its own thing... the pH Up drops are just a temporary fix to something which may not even pose a problem.

I used to use Earth Juice for many years, and still do some times. The Grow, for example, makes for notoriously acidic fertigation solution... pH 4-5. Many people online recommend aerating solutions before application, which after some time will cause the pH to raise. I didn't\don't typically do this, just made sure to put a heaping tablespoon of lime per gallon of mix before planting into it.
 

Po boy

Well-Known Member
a good peat based soil with dolomite added is all you need. ever see professional growers checking their ph all the time? i believe i read one of Uncle Ben's posts when he writes that he has never checked the ph of the soil. i been around pro growers for 40 years and never hear them talking ph. on riu people think that wrong ph is the center of all plant problems. what a waste!
 

plaguedog

Active Member
Talk to any experienced grower and they will tell you that one of the most important features of their grow is the ability to control pH. pH (which, as most people are unaware, stands for "potential Hydrogen") is of paramount importance to any hydroponic/soil grow operation because it affects the way that nutrients are absorbed into your plants. Many growers have long had an adversarial relationship with their nutrient solution's pH, but recent advances in nutrient technologies have made pH much more easily balanced within the nutrient reservoir, without the need of buffer solutions like pH up (an alkaline solution) or pH down (an acidic solution). Here is the lowdown on pH, how it affects your plants, and how you can keep it in that "sweet spot" that plants love.
Why pH Matters:
All green-leaved plants can survive just fine with a pH between 4.0 and 7.0. Basically, because the plants are made of relatively weak acids, they enjoy an environment that is also on the acidic side. However, when you are growing hydroponically, the nutrient solution that you provide to them is their life force, and nutrients will not be absorbed properly without the solution composed of the correct pH.

While the optimum pH for plant uptake may vary from one mineral to another, experts have determined that the optimum range for most of them is between 5.5 and 5.8 (DWC) and between 6.5 and 7.0 for soil, though many growers will argue that anything up to the 6.2 range is perfectly fine for hydroponics.
Minerals like Manganese (Mn), Copper (Cu), Zinc (Zn), and the especially critical Iron (Fe) have reduced absorption rates at a higher pH, while Phosphorus (P), Potassium (K), Calcium (Ca), and Magnesium (Mg) have issues being absorbed at a lower rate. This doesn't mean that no nutrients are absorbed at higher or lower pH levels, but why waste valuable nutrients because your roots essentially don't know that they are there?
Controlling pH
There are a variety of tricks to keep your pH balanced. Firstly, for God's sake, make sure you have a meter, and a good one. My advice to growers is that nutrients, meters, and lights are not the places to save money. Spend some dough on a great tri-meter (pH, ppm, and temperature), and you will have the best chance of knowing what is happening in your reservoir.
Also, invest in some simple aerators to keep the nutrient solution in your reservoir constantly circulating; this will add oxygen to your solution (which makes roots happy) and make sure that all of your nutrients are evenly distributed. Aerators are inexpensive and can be purchased anywhere from hydro stores to pet stores, and even Target or Wal-Mart.
To keep pH within that optimum range, growers have traditionally had to rely on buffer solutions, like pH up and down. While relatively inexpensive and incredibly effective, these buffers add unnecessary particulates to your reservoir, often causing your ppm meter to register a higher number than it would if it were only measuring your nutes (like it should). They are also extremely caustic and burn like hell when they come in contact with skin, especially both at once.

One trick of the trade that is lesser known and less commonly used (though can be effective if you know what you are doing) is to add excess levels of Phosphorus (P) to your reservoir. Because of the way that it interacts with the other nutes, it will work to keep your pH at an optimum level (for a while). The downside of this technique is that as you use the nutrient solution in your reservoir to water your plants, and it recycles back into the reservoir in a never-ending cycle, your plants will uptake not only the nutrients that you mixed for them, they will absorb that extra Phosphorus as well. So, when using this technique, the efficiency drops as you water your plants – nothing will be as accurate as a brand-new, freshly mixed reservoir.
Changing the Game
While the info here will allow you to have a successful grow and harvest (providing you do everything else correctly), it takes time, effort, and constant monitoring to keep pH at an acceptable level to your plants. Your little green buddies will absorb nutrients at different levels during different parts of their lifespan (veg vs. flowering), so your pH will be constantly changing, and not always in the same direction. It takes a dedicated grower (or an automated system) to stay on top of this.
I have said repeatedly to CHECK you water pH when growing hydroponically. Another pot forum myth is chlorine or chloramine in your water causing detrimental effects on plants in organic soil. http://waterquality.cce.cornell.edu/publications/CCEWQ-17-ChloramineDisinfectant.pd

I think I trust university studies over most anything posted here.
 

Jeffdogg

Well-Known Member
Dude it wasn't to prove or disprove, this is a forum where we can post based on what we want regarding whats being said. It seems like your going about trying to instigate, I believe that's the real problem at hand..
 

plaguedog

Active Member
What am I instigating here? I am just trying to educate people on the effects of pH'ing your water on the substrate you use, and back it up with FACTS with sources included. I've said what I had to say and provided the evidence that backs my claims.

People get all bent out of shape because they think they know what they are talking about, but in reality they don't.
 

Jeffdogg

Well-Known Member
Thats funny every time you make a closing comment like that your talking about yourself lol...
 

plaguedog

Active Member

Here is how accurate a soil pH probe is btw

SOURCE:Sam Angima, Oregon State University Small Farms ProgramPublish Date:
Fall 2010


VolNo:
Vol. V No. 4

 
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