I guess it might work. If its blue that means lots of sulfur and iron and acidity.

Well, I will attest to the fact that you CAN lower soil pH gradually with acidifying organic mulches such as oak leaves. Because, my Nikko Blue hydrangeas that always bloomed pink for years and years and years did turn blue, true blue, in the past couple of years after about 4-5 years of deep mulching with oak leaves every fall and spring.

However, I think this would be significantly less reliable and much slower than just investing in a decent soil pH test kit.

I just watch my blueberries and look for signs of low or high oh levels. I have been using very fine pine mulch and a layer of peat and I adjust the ph of water when hand watering.

I'm sure this is all over other threads, but I'm not convinced that the home soil pH tests are particularly accurate. And, I'm a guy, so I can't tell the difference between colors anyhow :P.

Getting soil from deep spots where the roots are would be damaging to the plant. I can only really apply acidifying agents near the surface, and can't get access to the soil near the deeper blueberry roots to test it.

I did send in my soil from 3 different spots in my yard/garden to my local university extension office before I started growing things 3 years ago, and the pH was 5.5, 5.5 and 5.7. So, I'm not horribly awry to begin with, I guess.

I now have 4 blueberry bushes in a 4'x6' rectangle. Sadly, the bigger guys are South or I'd go ahead and spring for a hydrangea in the middle just for kicks.

I just received my ph meter that I ordered online. My expectations were not very high. After receiving the meter I found out it tests water too. I didnt expect much...so I used it to test my water and I know my water is 7.4-7.7 (City tests for free) and my new Ph meter was DEAD ON! I left in the glass with ater for a while to. Even when I touched the tip to the side of the glass it would make the ph change. The meter is very sensitive but its not even electric.

So I then use it to test my soil. My mandarin that is in a pot still from the grower is growing GREAT. So I tested the soil. PH 6.4. So then I test my in ground navel that I just dug out all the grass from around it and layered year old cow manure and slow release MG 10-10-10 which I found out also has %20 sulfur. Anyways I covered it in bark and its been like that for a month. The plant is picking up in growth and i tested the soil in its 4x4 foot area. The soil is ph 6.6. So then I test other spots in my yard where I have never messed with the soil by adding nutrients or "amendments" Ph 7.6! I lowered the soil one point in my areas around my trees compared to the rest of my yard. In less than one month. I couldnt believe it! This meter is pretty decent.

http://www.garden.com/item/ph-meter/G24941/