testing soil PH
- Thread starter wlambeth
- Start date
The best option is to see if your ag extension does soil testing, because they will give you a lot of useful data. Second best is probably to get a fish test kit that uses drops.
If you are worried about bonsai soil, you probably shouldn't care about ph.
If you are worried about bonsai soil, you probably shouldn't care about ph.
TN_Jim
Omono
Before I moved from the plateau in TN, the water center was housed within the university, but independent of. Either way, where you live in the US you should have a place where you can take a jar of water or a container of dirt and have it analyzed for constituent parts..it is relatively inexpensive, I believe, if you are looking for pH, either way...tell them you want something more than a litmus test.
Knock on an ag professors door or email...you may be surprised...may not
True pH is hard to nail down...
@ysrgrathe, its the plants that require or are most acclimated to a...what do you mean?
TN_Jim
Omono
Yea...I guess I started typing there and realized, don’t know what you mean.
pH does matter...sure, you can grow a tree in a lot of different mediums, but just because you can, doesn’t mean you are maximizing the health and potential of a tree
you could blindfold and drive me out in the country, and I’d have a good shot of telling you the pH of the habitat by seeing plants and trees and not a single rock....
there are many different mediums people use for bonsai soil, and therefore different pH...for example, I’ve been using primarily de which is slightly alkaline....sure I could grow an azalea in straight de, but would that be the best choice for an acid loving tree?
Why should the pH of bonsai soil(s?) be ignored?
Mellow Mullet
Masterpiece
"Ignored" may be the wrong word for it, but pH is focused on too much when it comes to bonsai. It is really not worth all the fuss. First, the pH is very difficult to measure accurately without the proper equipment, i.e., lab type equipment. pH meters from the garden store, pH paper, and color tests at the pool store are not that accurate. So, if you can't actually measure it accurately, how are you gonna adjust it? Or, know if your adjustment was right? Any adjustment would be temporary anyway and would only last as long as it took to wash it out of the pot with watering or the chemical you used to adjust it got used up in the reaction. A good example is lawns, here in the deep South we have a lot of red clay, so the soil tends to be on the acid side. Each spring, we dump lime, along with some triple-8, on our lawns (most do, some don't fuss over it). The grass greens up and grows really well for a month or so, then slowly loses its steam as the rain washes the lime away, or deeper in the soil, and the lime gets consumed and used up.
We water every day (usually) so if you did adjust the pH of the soil in your pot, the adjustment would be washed out in a day or so. Plus, if you are using tap water, you are more than likely gonna have alkaline soil, even if you use a soil that is supposed to be on the acid side. City water is usually kept on the alkaline side because it is easier on the pipes and picks up less metals. Mine is 8.3 (I work in a lab and have access to ph equipment).
The best thing to do is to learn to recognize the signs of acid loving trees not doing so well in alkaline soils, the most common problem is chlorisis. This is easily fixed with a pinch of Ironite every now and then.
I don't fuss over pH. I love and grow many azaleas, in a mix of pumice, DE, lava, and fir bark. When they start to look a little yellow, I add some Ironite and they green right up. They grow like crazy, eventhough I am pretty sure I am not in the "proper" (as books say) pH range. I do the same with my junipers.
TN_Jim
Omono
Awesome!!! Thanks much, that nailed it (*exhale slow sigh of relief).
Leo in N E Illinois
The Professor
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John @Mellow Mullet is right on the mark. The measurement of pH is twisty, hard to nail down correctly. Biggest danger is getting inaccurate results and then adjusting water or soil that in reality did not need adjusting. And erroneous errors, adjusted to another erroneous result can drive the pH wildly out of ideal range.
Second, plants, pretty much all higher vascular plants actively excrete buffers through their root tips (* root hairs too), that buffer the pH of the water film immediately surrounding the root tip into the preferred range for optimal absorbing of nutrients. If the pH is not wildly out, the plant will take care of getting the pH right all by itself, no need to mess with the system. If you don't overwhelm the plant's capacity to buffer its own environment, they will be fine left on their own. This is true for most trees and shrubs.
pH is not even the relevant measurement, it is Total Alkalinity that is relevant. Total alkalinity is a measure of the buffer capacity of the water, a measure of the amount of acid or base needed to change the pH of a standard amount of water. Rain water has a buffer capacity less than 25 or 50 mg/l as calcium carbonate (depending on how much soot and dust is in the air when it rains). Well water can have a total alkalinity in the range of 600 or 800 mg/l as calcium carbonate. This means it would take 20 to 30 times as much acid to lower the pH of well water versus lowing the rain water to the same pH.
On the blueberry farm, we need to keep our soils in the acidic range, much more acidic than what azalea requires. Most of the time we depend on rain to water the blueberries. Rain has low total alkalinity, relatively pure water. We do nothing if it is just rain. When we have to water with water from our pond, during drought, we keep track of how many times we watered with pond water. Pond is 175 mg/l as calcium carbonate. We have a rough guess of how many gallons are pumped each irrigation. This is actually used to calculate a rough estimate of the number of pounds of calcium carbonate that were spread over our soils by the pond water. Then in autumn we spread the appropriate amount of elemental pelletized sulfur to neutralize and acidify that amount of calcium carbonate. The sulfur slowly dissolves over the course of a year or two and returns acidity to the soil. Through this whole process we never test pH, as pH is meaningless for growing blueberries. Total alkalinity is the only thing we check. The test costs roughly $12 per sample at a local private testing lab, done same day. Or about $10 each and wait a month for results from USDA Ag Extension Service.
Azaleas ain't that fussy. If you choose your media to be relatively inert to slightly acidic, try to water 2 or 3 times with rain water to every dose of municipal or well water, you will be golden.
Second, plants, pretty much all higher vascular plants actively excrete buffers through their root tips (* root hairs too), that buffer the pH of the water film immediately surrounding the root tip into the preferred range for optimal absorbing of nutrients. If the pH is not wildly out, the plant will take care of getting the pH right all by itself, no need to mess with the system. If you don't overwhelm the plant's capacity to buffer its own environment, they will be fine left on their own. This is true for most trees and shrubs.
pH is not even the relevant measurement, it is Total Alkalinity that is relevant. Total alkalinity is a measure of the buffer capacity of the water, a measure of the amount of acid or base needed to change the pH of a standard amount of water. Rain water has a buffer capacity less than 25 or 50 mg/l as calcium carbonate (depending on how much soot and dust is in the air when it rains). Well water can have a total alkalinity in the range of 600 or 800 mg/l as calcium carbonate. This means it would take 20 to 30 times as much acid to lower the pH of well water versus lowing the rain water to the same pH.
On the blueberry farm, we need to keep our soils in the acidic range, much more acidic than what azalea requires. Most of the time we depend on rain to water the blueberries. Rain has low total alkalinity, relatively pure water. We do nothing if it is just rain. When we have to water with water from our pond, during drought, we keep track of how many times we watered with pond water. Pond is 175 mg/l as calcium carbonate. We have a rough guess of how many gallons are pumped each irrigation. This is actually used to calculate a rough estimate of the number of pounds of calcium carbonate that were spread over our soils by the pond water. Then in autumn we spread the appropriate amount of elemental pelletized sulfur to neutralize and acidify that amount of calcium carbonate. The sulfur slowly dissolves over the course of a year or two and returns acidity to the soil. Through this whole process we never test pH, as pH is meaningless for growing blueberries. Total alkalinity is the only thing we check. The test costs roughly $12 per sample at a local private testing lab, done same day. Or about $10 each and wait a month for results from USDA Ag Extension Service.
Azaleas ain't that fussy. If you choose your media to be relatively inert to slightly acidic, try to water 2 or 3 times with rain water to every dose of municipal or well water, you will be golden.
Glaucus
Omono
You can't test soil pH. By definition, pH is the concentration of hydrogen ions in a watery solution. What people usually refer to is the effect soil has on the pH of neutral water.
There are several ways to have your soil in question affect the pH of, unusually, distilled water.
So the first challenge and variable in 'soil pH' is to select a method. The most accepted method seems to be to mix equal parts soil with distilled water. Though sometimes it is suggested you use a solution with some salts instead.
Alternatively, you could extract the soil with distilled water and only measure the filtered water. Or, measure water draining directly from the pot.
I don't think that the measurement of the water itself is a 'crapshoot'. Best way to test at home is to use a pH electrode. There are some affordable ones available that you can also calibrate yourself.
There is also a whole bunch of cheap ones.
You don't need to measure your pH with 0.01 point accuracy. Just that your measurement isn't completely off and you are taking bold actions based on a very faulty measurement.
pH can change quite a bit with temperature. So if you take very cold water and try to measure it, your pH will keep drifting downwards until it is room temperature (about half a point).
So if you do a two-point calibration, you measure at the right temperature, and you measure within your pH range, and your electrode is rated to be accurate to 0.1 of a point, your measurement should be sensible and useful.
Using pH strips of litmus paper is less accurate, but it can still be used. And it will tell you if stuff is on the acidic side, yes or no.
The point about alkalinity made by both Mellow Mullet and Leo are of course on point. But it the end, for nutrient solubility and therefore nutrient uptake, pH is maybe the most key parameter.
But so is the resistance to pH change by either your soil or your tap water (ie the alkalinity).
So yeah in the end you want to know 1) pH of your tap water 2) pH of your tap water with fertilizer 3) pH of your RO water with fertilizer 4) pH of your well water 5) pH of your well water with fertilizer 6) pH of your garden soil 7) pH of your potting soil 8) pH of your old potting soil from a mature plant 9) pH of your garden soil right around the roots of your plant 10) alkalinity of your tap water 11) alkalinity of your garden soil.
And you see you are going crazy and overboard with all of this.
There are several ways to have your soil in question affect the pH of, unusually, distilled water.
So the first challenge and variable in 'soil pH' is to select a method. The most accepted method seems to be to mix equal parts soil with distilled water. Though sometimes it is suggested you use a solution with some salts instead.
Alternatively, you could extract the soil with distilled water and only measure the filtered water. Or, measure water draining directly from the pot.
I don't think that the measurement of the water itself is a 'crapshoot'. Best way to test at home is to use a pH electrode. There are some affordable ones available that you can also calibrate yourself.
There is also a whole bunch of cheap ones.
You don't need to measure your pH with 0.01 point accuracy. Just that your measurement isn't completely off and you are taking bold actions based on a very faulty measurement.
pH can change quite a bit with temperature. So if you take very cold water and try to measure it, your pH will keep drifting downwards until it is room temperature (about half a point).
So if you do a two-point calibration, you measure at the right temperature, and you measure within your pH range, and your electrode is rated to be accurate to 0.1 of a point, your measurement should be sensible and useful.
Using pH strips of litmus paper is less accurate, but it can still be used. And it will tell you if stuff is on the acidic side, yes or no.
The point about alkalinity made by both Mellow Mullet and Leo are of course on point. But it the end, for nutrient solubility and therefore nutrient uptake, pH is maybe the most key parameter.
But so is the resistance to pH change by either your soil or your tap water (ie the alkalinity).
So yeah in the end you want to know 1) pH of your tap water 2) pH of your tap water with fertilizer 3) pH of your RO water with fertilizer 4) pH of your well water 5) pH of your well water with fertilizer 6) pH of your garden soil 7) pH of your potting soil 8) pH of your old potting soil from a mature plant 9) pH of your garden soil right around the roots of your plant 10) alkalinity of your tap water 11) alkalinity of your garden soil.
And you see you are going crazy and overboard with all of this.
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Mellow Mullet
Masterpiece
Glaucus
Omono
The alkalinity of tap water is more important than it's pH because the pH of tap water will change when it comes into contact with the soil.
The question is how much. The extreme example is that if you have distilled water, it has zero alkalinity and the pH it becomes after soaking reflects what we usually refer to as 'soil pH'.
The pH of distilled water by itself is also kinda a nonsense value because just breathing CO2 gas into it, or even stirring it, will make the pH increase.
But if you have soft tap water with some alkalinity and maybe an above 7 pH already, then this pH is somewhat buffered.
And if you have hard water with high alkalinity, you are adding lime to your soil and creating a high pH buffer environment in your soil, competing with the natural lower pH buffering the soil has, thanks to humic acids and similar substances.
Which is why Leo says that at their blueberry place, they just calculate how much CaCO3 they are adding per hectare. To then neutralize this carbonate once more with elemental sulfur, creating sulforic acid, creating CO2 and degassing the carbonate out of the soil, preventing lime build up, returning the pH to it's original and low value. I wouldn't say that the pH of the soil is completely irrelevant. But this is the basic process, their testing and bookkeeping, and how they manage it at this farm.
Yup
Glaucus
Omono
This is a good guide, I would say:
Purdue University, Commercial Greenhouse Production: pH and Electrical Conductivity Measurements in Soilless Substrates
Purdue University, Commercial Greenhouse Production: pH and Electrical Conductivity Measurements in Soilless Substrates
Glaucus
Omono
Sorry, yes stirring dissolves CO2 gas into the water, resulting in carbonic acid, resulting in bicarbonate and a hydrogen ion. I actually wrote it correctly, then somehow changed it. And then later on the day I was like 'all those hours at the pH meter, and I wrote down that. What the heck!"
roberthu
Chumono
There are places that sell test kits. You can use the kits to send in sample for ICE analysis. Triton is one of those companies that I have used when I kept reef aquariums. It takes about 1 months to get your results back but it is as accurate as it gets.
The test kits used to be $25 about 3 years ago. I just checked again and it is $40 now...
The test kits used to be $25 about 3 years ago. I just checked again and it is $40 now...
Glaucus
Omono
A month? That's extremely slow. If you run a company growing plants. Or say a company breeding clown fish. And you want your soil, water, plant tissue tested, you kind of want the result in 1 to 3 days.
Yes, there are colorimeter tests you can do yourself, with droplet liquids or even test strips.
But for double the money you can get a handheld pH meter that also measures EC. Bluelab and Aquamaster are two brands. On top of that, you can gamble on a rando Chinese one from Amazon for half or third the money, which might work just as good.
Such a thing is essential if you do hydroponics of some sort. It will instantly give you a result. And allow you to fine tune either your water your nutrient solutions. Or your reef tank or aquarium.
roberthu
Chumono
I am not sure if the Amazon test equipment are as accurate as ICP tests. Once the lab receives the sample, they basically burn it and analyze the spectrum of the flame to determine the elements including trace element and quantifies it to parts per billion. PH is just a byproduct of this test. If accuracy is what you are after, this is the way to go in my opinion. And it shouldn't be something that needs to be done regularly. In my 6-7 years of reef keeping, I had only done it 2-3 times to make sure my water was on point.
When I did the tests, it took about a week to just ship the kits back to the lab. Then it took somewhere between 2-3 weeks before results were ready to be viewed. Maybe it's faster now that most people are back to work in the office.
Glaucus
Omono
Sure, but at some point, the accuracy that a lab has is pointless. You don't want to estimate if there are 55 or 56 cocaine users peeing in your neighbourhood sewer based on ICP-MS that is able to detect nanomolair concentrations of of cocaine metabolites with picomolar error margin. It's pretty cool, but for a reef you just need to know what parameters you adjust so your reef thrives.
For a company offering soil and water quality checks, or even leaf samples, you'd do it within a day. Even DNA sequencing is now done in a few days. A courier visits, picks up everything and delivers it to the lab. Next day, they run the analysis. Then at the end of the day, you get a link in your email for the result. That's not needed for basically anyone on this forum. But that's what happens in industry.
They can also do way more types of analysis. Which may indeed be handy for a reef lab. I knew a tiny bit about that, but never too much and I forgot most. You can't buy a sensor measuring ammonia, nitrites and nitrates at the accuracy required for a reef thank for under 100 USD yet. But if your ammonia or ammonium level are way too high, you don't want to wait 1 months for it either. You'd probably need 0.1 mg/L accuracy, maybe 0.01mg/l. Actually, it seems that some of these sensors exist of for the consumer market already. In 5 to 10 years, this may be a base thing for serious all reef tanks. You'd get a push message on your phone the moment your water values go outside a certain range. Beats the 1 month wait.
For a company offering soil and water quality checks, or even leaf samples, you'd do it within a day. Even DNA sequencing is now done in a few days. A courier visits, picks up everything and delivers it to the lab. Next day, they run the analysis. Then at the end of the day, you get a link in your email for the result. That's not needed for basically anyone on this forum. But that's what happens in industry.
They can also do way more types of analysis. Which may indeed be handy for a reef lab. I knew a tiny bit about that, but never too much and I forgot most. You can't buy a sensor measuring ammonia, nitrites and nitrates at the accuracy required for a reef thank for under 100 USD yet. But if your ammonia or ammonium level are way too high, you don't want to wait 1 months for it either. You'd probably need 0.1 mg/L accuracy, maybe 0.01mg/l. Actually, it seems that some of these sensors exist of for the consumer market already. In 5 to 10 years, this may be a base thing for serious all reef tanks. You'd get a push message on your phone the moment your water values go outside a certain range. Beats the 1 month wait.
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