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Lowering pH for Blueberries using Muratic Acid (nitric acid)

Posted by nugent 8 (My Page) on
Wed, Jun 23, 10 at 9:55

I have a high sulfur content in soil and a pH of 6.5. Can I lower soil pH using diluted muratic acid (nitric acid)?
Soil is also low in nitrogen. Sulfuric acid or sulfur addition would not be best for me to use to lower the pH.


Follow-Up Postings:

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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

What makes you think you have high sulfur in your soil? If you do, the bacteria would break it down and lower the pH. Even if you have high sulfate, such as a lot of gypsum, you could still add sulfur.

But you could use nitric acid. The only problem might be if it causes nitrogen to be too high and the plants grow too vigorously.


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

Muriatic is not nitric, but hydrochloric.


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

I would just use White Vinegar. Its easy to find and easy to use and a slip or spill will not be a hazard.


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

  • Posted by olpea zone 6 KS (My Page) on
    Wed, Jun 23, 10 at 17:28

Mark's right. Muratic is simply hydrochloric acid, albeit in a form that contains a higher level of impurities.

Most fruit plants/trees do not like chlorine. That's why muriatic acid is generally not recommended.


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

I have to ask about buffering. It would be my thought that using any acid straight would result in a large drop in pH but a very transient one. Is the acid being used very dilute in drip irrigation, or is the pH being frequently monitored and adjusted? It seems cumbersome compared to a buffered system that would maintain a given pH over a range of conditions.

An acid salt that would "break down" gradually (not a good description of how buffering works, but OK for now) would seem a better choice to me.

M


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

  • Posted by tims WV 5 (My Page) on
    Thu, Jun 24, 10 at 19:34

One tsp. battery acid(sulfuric acid) From advance auto should take a 7ph of tap water to between a 5 or 6 ph in a two gallon watering can,and no it doesn't contain lead.


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

This is where you gotta have your soil test results handy...

The key here is Your current PH and the soil's "Buffer PH" -- If your actual PH is close to your Buffer PH -- You are up against the proverbial "Brick wall" -- A huge amount of acid or base won't change the PH much....

If your actual soil PH is farther away from your Buffer PH -- you will be able to swing it fairly easily (Though it will swing back just as easily....)

In the case of My soil -- PH = 5.0, Buffer PH = 7.2, so I could make a little amendment to raise or lower my soil PH by a considerable amount fairly easily, but it will swing back just as easily.... until I get close to 7.2... where it will stabilize and SIT if I get it there (Which I really don't want....)

Now...
On Muriatic acid -- It is just HCl -- Hydrochloric acid... It is a "Strong" acid... so it certainly does have the power to change your soil's actual PH... All the way past "Tingly" where it will rot rubber tires...

Unfortunately, there is another magical thing called "Common Ion Effect" -- which is how Water softeners work.... which means when this gigantic amount of Chloride hits the soil -- it dissolves very well and kicks everything else out of solution... It makes many other minerals precipitate out (Bind up)... (stuff like Nitrates, sulphates, Stuff your plants need to live... etc...)

You may be better off mixing in a bunch of Peat moss, pine needles, and sulphur, and then fertilizing with "Camellia, Azalea, and Rhododendron" fertilizer....

Thanks

John


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

Horticultural discussion and nonprofessional writing are rife with "folk chemistry," which often involves processes that real chemistry might marvel at. One is best here to accept good experiences and proven practices and perhaps not pay too much mind to the supposed explanatory details behind them. More important, don't venture farther, that is to outside of those experiences, based on inferences from those supposed explanations. Many are correct, certainly, but many are myth or misunderstanding.


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

Grow your blueberries in a raised bed of composted pine bark and dress with pine needles. The pH will be plenty low. this is a proven method for blueberries. Then use a fertilizer for acid loving plants. Don't mess with muriatic acid, too dangerous and not necessary!. Water with rainwater.


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

I'm wondering why you are trying to lower you PH? 6.5 is already acidic. Just use a good mulch and you should be fine for most plants including blueberries.


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

John: very well stated, couldn't have explained it better myself even after coming out of college when I remembered all that stuff!


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

Chloride, if relatively concentrated, can desorb (that is, release to solution, not bind up) other anions that are already sorbed to soil organic matter or more-layered clays (and sorbed is right where we want them if they are nitrate, phosphate, or to a lesser extent, sulfate, because they don't leach and plant roots can still get them). Chloride would neither tend to precipitate nitrate nor to have it sorb, in the latter case just the opposite.

The very old practice of fertilizing asparagus with salt is thought by some to have involved triggering desorption of a limiting cation (e.g., iron, calcium, magnesium, manganese) by the sodium or else a limiting anion (e.g., nitrate, phosphate) by the chloride. The former was more suspected.


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RE: Lowering pH for Blueberries using Muratic Acid (nitric acid)

John comes close to addressing the point I was trying to get an answer to, but I still am confused as to why it would be worthwhile to use a simple acid solution to lower pH when the effect would necessarily be transitory. Irrigation would constantly dilute and remove the acid, so you'd have to constantly replenish it. Why wouldn't one just use a buffering salt in the first place?

I realize that in situ the acid is going to react with other stuff, and may even form a buffer in the process, but that would be up to chance.

There's enough old hippy in me to suspect we'd be better off getting to the pH we want by having all the other soil factors where they should be, so I'll second Mr.Texas suggestion of composted pine bark with a pine needle mulch, which is how Mother Nature does it in the woods.

"So little time, so much to learn ..." :-)

Thanks,

M


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