You might have mentioned if this was garden soil or a container media. "Is it the acetic acid or something else in vinegar that makes it harmful to plants?" Acetic acid causes the rapid dissolution of cell membrane integrity, which causes dessication and destruction of foliar tissues when topically applied. Acetic acid is non-selective, and may damage any plant part contacted by the solution, if the solution is strong enough, 'strong enough' being a key phrase. Acetic acid has a variable affect on plants, the greatest being on young seedlings (less than two weeks after germination) and plants with foliage low in cuticular waxes. Topically applied, vinegar is not transfered from foliage to roots, so perennial plants that are topically treated with vinegar would quickly regenerate from rootage. I know I'm straying into the realm of vinegar as a herbicide - not something you asked particularly about, but I thought it might be interesting to know a little about the mechanism so you could understand how it's use might affect your plants. I have been using vinegar regularly in the winter on my bonsai & houseplants under lights for many years to neutralize my tapwater's alkalinity & prevent pH induced Fe deficiencies. Used at an ounce or two.gallon of water, I've found it to be a useful tool. "Does the interaction with the calcium carbonate neutralize vinegar's deleterious effect?" Yes - eggshells still in the solution is indication that there will be no ill effects from acidity. I will stand for correction from REAL chemists ;o), but the reaction should be something like: CaCO3 + 2 CH3CO2H ----> CO2 gas + H2O + Ca(+2) + 2 CH3CO2(-1) ".... is there another element that could be introduced that would neutralize vinegar's herbicidal properties while retaining (or possibly even adding to) any beneficial elements? (just enough baking soda to balance the ph, for example?)" Many elements and compounds, but none that I can think of that would have the benefit potential of CaCO3. You do know you're playing with fire? If you don't get the right amount of Ca in the soil in relationship to Mg, you can create an antagonistic deficiency of Mg (even if there is adequate Mg in the soil, not to mention that over-supplying Ca unnecessarily raises the EC of and TDS in the soil solution. This could even be compounded further if you suddenly discovered you need to add MgSO4 to balance the Ca/Mg ratio so Mg becomes available again. I agree with Dan. It makes no sense (to me) to use eggshells when dolomitic lime supplies both Ca and Mg in a favorable ratio. Dan - Please clarify something. During periods of rapid transpiration, Ca is very available to plant organs, including fruit. It's during periods of high humidity, and especially on dull days when the nutrient stream is at a virtual standstill that weather-induced Ca deficiencies occur. If you used the term 'evapotranspiration' in the classic sense, to include...

Can citric acid in water be used as a substitute for vinegar? In theory, yes. But not in practice because the pH of the end result wouldn't be standardized. It would depend on your water's pH which varies wildly. 1 t to a quart my well water here in "limestone heaven" would still be way on the alkaline side of the scale and so be very different from your city water. Linda Lou's crucial point was that you need the total amount of liquid called for to control the density. Density in a recipe is just as important as pH and if you reduce the liquid you increase the density and so invalidate the processing time because you have slowed the heat penetration. If you don't want to use the vinegar then the approved alternates are wine vinegar that is 5%, or bottled lemon juice or lime juice. You can use a mixture of any of those as long as you keep the 2 1/2 cups total the same. Dave

Well there is always sugar but in this case I think I'd go with lots of carrots for sweeting it. They would blend in with all the other vegetables and if they don't add enough to off-set the vinegar - doubt you can cover all of it - you can always add a bit of sugar. Dave

Aztcqn: I'm so sorry that you lost your Capitaine John Ingram rose. From the look of its leaves and many thistle, it has Rugosa Heritage, which dislikes chemical fertilizer and prefer loamy/sandy soil. Sulfate of potash is NPK 0-0-50, very high potassium and blood meal NPK is 12-0-0, very high in nitrogen. Agree with what you wrote: "Perhaps this one needed and liked a more acidic home....." Rugosa doesn't like alkaline clay in my Chicagoland, nearby decade-old Rugosa hedge refused to bloom, died off, then its multiflora-rootstock took over. A California rose-grower stated "no granular fertilizer after June 1st", and I agree. I put granular fertilizer (blood meal & chicken manure) in early spring with tons of rain, but after June 1st, I use SOLUBLE fertilizer. We get hot weather up to 80 in June. I pre-mix molasses & sulfate of potash in a water-bottle, then put a tiny sip (less than 2 teaspoon) per 5-gallon bucket of water. I used to put gypsum in that bottle, but my tap-water is so high in calcium, gypsum (21% calcium) tends to gunk up at the bottom of the bottle. Yesterday I had to scrape off that gooey & thick sludge of gypsum at bottom of the bottle. Rugosa-genetics doesn't like free-lime (calcium) as in gypsum or lime since calcium thickens the soil, and Rugosa prefers loose & loamy or sandy soil. Blackstrap molasses has plenty of calcium, potassium, a bit of phosphorus, and 20% iron to make it a cheap SOLUBLE fertilizer. I never burn any roses with that. To lower high pH tap-water, I dunk used-lemons in the bucket. Drawback of molasses: attract flies. Brewer's yeast is cheap, high in potassium & some phosphorus, all the B-vitamins and VERY ACIDIC, a tiny bit is enough to lower high pH-tap water. http://espace.library.uq.edu.au/view/UQ:325522 " To explore the potential relevance and practical application of rhizophagy, we investigated brewers' yeast (Saccharomyces cerevisiae), a waste product of the brewing industry, for its role as biofertilizer. The addition of live or dead yeast to fertilized soil substantially increased the nitrogen (N) and phosphorus (P) content of roots and shoots of tomato (Solanum lycopersicum) and young sugarcane plants. Yeast addition to soil also increased the root-to-shoot ratio in both species and induced species-specific morphological changes that included increased tillering in sugarcane and greater shoot biomass in tomato plants. These findings support the notion that brewers' yeast is a cost-effective biofertilizer that improves not only plant nutrition but also plant vigor during the early growth phase. "