I'm just tossing out a random idea, perhaps a terrible idea. Some people suggest using vinegar as a spot-weed-killer.
But could you use it to neutralize some of the alkalinity?
Vinegar certainly is an acid - acetic acid.
https://www.amazon.com/dp/B008GTGE7U/
https://www.amazon.com/dp/B0052E9BH2/
20% Horticultural Vinegar, 4 gallons for $52 or single gallons for $16.
Household vinegar is 5%, so ag vinegar is 4X as strong.
I guess if you use it only to neutralize the well water, you can't kill any plants with it. I wonder how much you would need to neutralize 10 square yards of pH 8.5 soil? My guess would be "LOTS".
At least it will be broken down to CO2 and nothing else by soil organisms. It's pure organic "brown" in composting terms.
>> Twelve teaspoons of Epsom salts
Hmm, that's two ounces if they were level teaspoons. It wouldn't surprise me if two ounces of household vinegar neutralized a half gallon of well water. You might have to use an eyedropper with the agricultural-strength vinegar.
But as Dave says, that depends on "total alkalinity", like the concentration and buffering power of your minerals.
When I was a kid, I used to think: "why not use dilute nitric acid? That would even add nitrogen!" Having worked since then in a chemical plant with concentrated nitric acid, I don't even want to THINK about it.
Plus, today, the potential for using nitric acid to make explosives would probably "get us on a list" for just thinking it.
