Is diluted sulfuric acid safe to lower ph

Discussion in 'Soils, Fertilizers and Composting' started by hman, Nov 14, 2008.

  1. hman

    hman Member

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    My garden's soil ph is way too high and I know adding sulfur will lower it by slowly allowing soil bacteria to turn it to sulfuric acid. Has anyone added say 1-2% acid to water to acidify the soil faster? I worry about burning plant stems or roots.
     
  2. jimmyq

    jimmyq Well-Known Member 10 Years

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    How high is the pH, what kind of soil is it, are there plants growing in it now and if so what are they?

    I have recommended elemental sulfur to lower soil pH before, I think it was one pound of sulfur to about 100 square feet to lower about 1 point. I havent used a liquid form before, I would think it would be dangerous to handle.
     
  3. hman

    hman Member

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    I have clay soil at ph over 8 I want to get to 6-6.5 for vegetables. I've handled acid before and is very safe once quite diluted, yet may have to try it in my mulch pile first to see how the volunteers do with it.
     
  4. LeftCoastAngler

    LeftCoastAngler Active Member

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    I think vinegar will bring your pH down.

    ~LCA.
     
  5. lorax

    lorax Rising Contributor

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    I'd use vinegar or mix in some pine needles. No need to be extreme!
     
  6. jimmyq

    jimmyq Well-Known Member 10 Years

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    Vinegar should do the same as any acid, I believe household vinegar is 5% acetic acid commonly. I have seen it sold at 10% as a non selective herbicide.
     
  7. growing4it

    growing4it Active Member 10 Years

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    You might want to consider a less extreme product than sulphuric acid to change the pH. I didn't think that sulphuric acid was commonly available. Sulfuric acid or acetic acid (vinegar) in liquid form would be a quick but temporary solution to your clay soil pH. Jimmyq suggested elemental sulfer.

    For a long term pH change and other improvements I would think that you'd have to change the soil - with regular organic soil amendments such as compost or manure. Clay soil is not really suitable for vegetables, I thought, because it's too heavy and because of the pH.
     
  8. growest

    growest Active Member 10 Years

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    I can pass on what I've heard in comments by Elaine Ingham of Soilfoodweb, who is an expert on soil biology.

    She has observed damage to soil microbes using any forms of sulphur, which is a natural fungicide. Ironically, it is the fungi in the soil which naturally alter the pH in the acid direction. Thankfully, most plants are able to alter the soil chemistry in the immediate area of their roots by encouraging beneficial microbes with root exudates, creating a pH much different than that in the overall soil. Anything that supports good soil biology will help with your situation.

    Any liquid addition would be temporary, as it would leach out rather quickly in our high rainfalls...tho at least acetic acid is quite a "natural" chemical from a biochemistry viewpoint. On the other hand, various microbes would certainly consume it, so it would disappear even quicker than sulphuric acid. It would need to be applied regularly to lower pH on any long term basis. My understanding is that this continuous addition of acid is just what is happening with a good population of soil fungi, which produce chemicals similar to acetic acid to push their environment in the direction they prefer.

    There will be a limit to what can be done biologically tho...I'm quite interested in what might produce a clay soil with pH of 8 in our region. A soil test including the base saturation might solve the mystery, (tho still not improve the soil!). I've heard of strange soil types in the western mountains, called serpentine, that can be quite challenging to grow many things...wonder if yours is anything like that.

    My native soil is around 6.8 and even I can't grow blueberries and many rhodo's well...and that's with following my own advice, smile...

    The suggestion about changing the soil seems drastic, but is likely the only way to grow many of these acid lovers in our situations. The clay texture of your soil would be another encouragement to just bring in new stuff...I don't envy you your challenging garden.
     
  9. hman

    hman Member

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    I greatly appreciate all the help and realize that instead of rotating crops I may have to rotate (replace) my soil. I am in the process of mulching and adding more compost, but will try adding about 3% vinegar to my mulch pile watering and see if the starts there survive and if the ph lowers and for how long. We're all learning and the sharing on this site helps us all learn more.
     
  10. Ron B

    Ron B Esteemed Contributor 10 Years

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    Each pH point represents a huge difference. Applying enough of a chemical to change the pH even one point over a short period of time is liable to be highly disruptive to the soil system. If you can't do it gradually then you shouldn't try it. Dumping more suitable soil on top of the existing plot and avoiding mixing the two layers together may be all that you have to do. If these are already raised beds (a good idea for vegetable production in a cool climate) then you may have to dig them out (if contained) or shovel them off first.
     
    Last edited: Nov 18, 2008
  11. Pharmerphil

    Pharmerphil Member

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    Stick with the elemental sulfer and compost.
    I use acetic acid (56%) "vinegar on steroids", for permanent weed elimination, but Not...in the garden
     
  12. hman

    hman Member

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    several organic farmers told me that elemental sulphur is very slow and interferes with microbe activity, but that coffee grounds add a little acidity.
     
  13. growing4it

    growing4it Active Member 10 Years

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    Starbucks packages the used coffee grounds for composting which are free for the taking. I'm sure other coffee shops might do the same. Coffee is acidic and compostable.
     
  14. Lysichiton

    Lysichiton Active Member

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    The basic premise I have worked sucessfully with, is that a annual application of well-rotted compost acts to both decrease the rate of nutrient loss from the soil & to buffer pH values, keeping them toward the neutral range. I have not had to resort to chemical pH amendments since I started annual, heavy mulching of the vegetable area with compost. To raise the acidity around my blueberries & mulch with coniferous needle debris (scrounged from my neighbour) - works a treat.

    gb
     
  15. Ron B

    Ron B Esteemed Contributor 10 Years

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    Local soils are usually acidic. In fact, cultivation practices and acidic precipitation are liable to be making many sites too acidic. When I belonged to the local rhododendron society over 30 years ago the newsletter writer was starting to tell members to think about putting dolomitic limestone on their rhododendrons each January.

    Don't mess with your soil without sampling it and having it tested. Re-testing needs to be done to monitor the situation.
     
    Last edited: Nov 25, 2008
  16. mikeyinfla

    mikeyinfla Active Member

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    i agree with the raised beds instead trying to change the soil ph if it is 8 and you want to go to 6.5 that will take a good number of years and probably the amounts of acid you would have to add would be expensive and might harm the whole yard and any existing plants. with a raised bed you can add what you want to it topsoil with compost and cow manure than mulch it with pine needles or oak leaves or whatever mix you want to add i think it would be less headaches.and not as dangerous
     
  17. Sam Hamby

    Sam Hamby Member

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    I live in a low rainfall desert (<7 inches per year) where the soil pH can be 8.5 or higher with caliche and municipal water supplies have a pH of 8. Soil acidification is usually achieved with elemental sulfur and acid forming fertilizers. But with such severe alkalinity here, I have used dilute sulfuric acid with good results.

    1) ONLY use sulfuric, or phosphoric acids on soils. All other common acids including acetic acid (vinegar) are toxic to plants.

    2) Use very dilute solutions in large quantities. The most common forms of sulfuric acid are conc. 98 percent (very dangerous to use) and clean pure battery acid available from battery stores in 1 liter bottles. Always add acid to water to minimize the reaction when they mix.

    3) For very alkaline soils, use 0.5 ml (C.C.) of battery acid (30 percent sulfuric acid) per gallon of water to create a solution of about pH 3.2
    4) Soak you soil in water and drench with the very weak acid solution. It will take a lot of solution over many months of once a week watering to drop the pH to 6.5 or below. A proportioner injector works well or irrigation systems or use 5 gallon buckets or a large wheelbarrow to mix large batches.

    5) Typical example: My irrigation system uses mushroom bubblers to deliver 6 inches of water to my tree wells and beds (about 25 minutes run time). It then shuts off, the water drains in 1 hours of less and I wait 2 more hours and water another 25 minutes. This deeply soaks the silty clay soil and flushes out salts and promotes deep roots. I do this once a week from spring (feb) to late fall (sept) where high temperatures are 80 F to 115 F and humidity is between 5 and 50 percent. Use the acid drench between the two watering cycles. I estimate I use at least 500 gallons of water total per week of water for trees, bushes. I have used this method on grass lawns also.

    6) The alkaline water here will keep trying to raise the pH. Test you soil pH at 12 inch depth and slow down or stop your acid treatments when you soil pH reaches 6 to 6.5. This can take weeks, months, or years depending upon you area. It is much faster than soil sulfur and acid fertilizers can do. The soil here has lots of calcium in it which become calcium sulfate (gypsum) using this method and help loosen the soil and release trapped nutrients. Use caution as toxic levels of locked up nutrients may be release too quickly as the pH drops below 7. That is why the deep heavy watering is used. As the pH drops you will find you may not need as much fertilizer.

    7) Use caution, sulfuric acid is highly corrosive to all tissue. Use eye protection and a precision graduated cylinder to measure the battery acid. Never use the 98 percent concentrate. It is too dangerous for non-chemists to use. Make sure the battery acid is pure, water clear, and not recycled. Phosphoric acid is also usable at 0.2 ml of the 85 percent concentrate gallon of water. Use caution with this acid also.

    8) Do not try to rush things and use stronger solutions as you will cause root damage and wilting. If nothing is growing in the area before you plant you can increase the acid strength 10 fold and drench until the pH remains 6 for several weeks. Residual alkaline salts in the soil may take a while to neutralize and flush out.
     
  18. MThuck

    MThuck Member

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    I wonder the same question. If I add sulfur to the soil and then add water with sulfuric acid in it, wouldn't this lower the ph much faster and last longer? I am in the process of amending some soil starting at a PH of about 7.0 or so for a raised bed for Mountain Huckleberries to around a PH of 5.5 - 6. I am using compost, Peat Moss and mixing some coarse granite sand in it for drainage. I understand that it takes sometime for sulfur to lower the PH. I would like to treat the soil now with some acid water and sulfur allowing the soil microbes break down the sulfur and have some time to get the bed ready for planting in April or May.
     

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