Excellent... thank you, SO. I think chemistry was my worst subject in high school, so having you summarize that simply and plainly is much appreciated! No danger of getting our soils anywhere near 6, eh? lol We must have excellent buffering qualities (hope I'm using that term correctly), though, because the efforts to lower pH here seem to be sticking better than areas such as daninthedirt is speaking of (great username, by the way, Dan). I also have a rather easy time lowering water pH for our aquarium fish; half distilled and half dechlorinated tap water keeps it in a comfortable range for them without having to purchase adjusting chemicals. (We're now on the river water pipeline that goes into town; well water was much, much worse and I could only use a small amount mixed with the distilled.) We're rural in the Humboldt area, but we have family who is mixed farming the Young/Allan area. :) Prairie Garden Seeds is in Humboldt here and I met Jim and his family briefly when I picked up a seed order last year. Nice folks. I should ask for a tour of the seed gardens someday. One more question. Our garden has flooded before. How long does it take for the iron to then get back to an unavailable state after such an incident? So as not to hijack crabbygardener's thread any further (sorry about that), I'm going to spin off with a new post over in the soil forum regarding my question about zinc and copper. This post was edited by macky77 on Sun, Mar 16, 14 at 11:29

If drainage is a problem, you can use sand if you create mounds for the plants using a great deal of sand. A little sand can actually make things worse from research I've seen, but if you use something like a third sand by volume, mixed with a third peat and a third soil and create the mounds with this it should work fine. If you make such a mix without building mounds you may create bath tubs that fill with water and drown roots. You can also grow them in pots mixing 50/50- sand to peat and put them half way into existing soil- or make a mix with ground pine bark that is aged for the purpose (this is harder to find but more often used in blueberry production). If you set up a drip system or water them consistently, blueberries grow very well this way, if you put them in big enough pots. 5 gallon pots would support mature plants pretty well. Is your soil clay? Do you know the texture of your soil? This is something that is not at all obvious and people often are confused about the texture of their soil. This is also where your county cooperative extension can provide better advice than you can get on-line- although there are simple tests using dishwater detergent to get a general reading on your soils composition. Drainage is easier, because you can figure out how long it takes to drain after heavy rains or dig a hole and fill it with water several times. Not sure of the exact procedure but it is an easy search for details.

I'm posting on this OLD post because it still comes up at the top of google search for "citrus peels lower soil ph" ... I have been doing tests with Citrus Peels.... I have found that about 30 good size grapefruit peels blended up in a blender (lots of batches of blending) with half water/half citrus in the end, produces a good acid base. I did enough to fill 30% of a 5 gallon bucket, which I then diluted to a full 5 gallons of liquid. This was then diluted 5 fold to register a drop in pH of 1 for the water... This diluted citric acid can be used similarly to sulfuric acid dilute. There is a company here that sells Moon Juice which is a combination of sulfuric acid + iron and other trace minerals... It's used for temporarily lowering the ph so trees and shrubs and such can uptake iron and other minerals that lock out at alkaline pH Levels... Given that we're in the southwest we have an ABUNDAND supply of citrus and over time, this is the same effect the trees fruit would give to the soil if there were no humans to tend to and pick the fruit... the fruit would rot on the ground, the citric acid would leach out into the ground as it decomposes and maintain a more acidic soil balance for the trees long term support... So can you use citric acid to dilute, yes you can, though, just like with a sulfuric acid dilute, you're going to need to apply it regularly (monthly or so depending on ph plant/etc) until the bacteria that feed on the sulfur have had enough time to lower the soils actual ph levels ... Something that seems to be long forgotten as I read some of these posts is... all living things have a pH, you can burn things by dropping ph too fast, or by raising too fast, so obviously some of the responses regarding putting acid next to the roots are appropriate, they are also inappropriate because your obviously not going to dump straight acid on anything unless your intention is to utilize the full strength of the acid :P Good Luck! Would love to hear about what you've done and how it's developed since your original questions!

I am using agricultural sulfur to lower pH around our blueberry shrubs, for 14 years now, so I know how to apply and also how to measure pH. Sulfur is not an acid, it must be metabolized by bacteria in the soil, and slowly converts to sulfuric acid, over time, typically one year. The soil pH will be variable during this time, and after all the sulfur has been used up, it will very gradually rise, due to the effect of the surrounding soil and subsoil. If you are watering your roses with tap water that contains calcium and/or magnesium, then the pH will rise over time. Soil pH can be measured by taking a soil sample, mixing it with distilled water, and filtering the mixture to get about one teaspoon of filtrate. This sample is then mixed with several drops of bromothymol blue indicator, and the resulting color indicates the pH. Blue = pH 7.6, or higher. Yellow = pH 6.0, or lower, and varying shades of green mean the pH is between 6.0 and 7.6.