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pH Measurement
I garden on "Cheltenham Sand" which according to
http://www.gloucestershire.gov.uk/me...ded%20appendix %20%20D.pdf is "composed of medium grained quartz sand with limestone fragments and gravel lenses" I've measured my soil pH several times with the 1 pound soil testing kits and it always comes out at slightly alkaline which is what you'd expect. Recently I bought a probe type pH meter and found: - Nowhere in my garden is alkaline according to the probe - even places that I limed in the Winter! - A lot of places have a pH of around 6. This includes a tub of erricaceous compost where a blueberry is living happily. - I've even found spots with a pH of 3.5 but a few inches away, it's a more reasonable 6. - Unused multipurpose compost has a pH of 6 - I tested the probe with plain water and got 7. A splash of orange into the water moved the reading down to 6 Anyone think anything is going wrong here? Steve Harris - Cheltenham - Real address steve AT netservs DOT com A useful bit of gardening software at http://www.netservs.com/garden/ |
#2
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"Steve Harris" wrote in message ... I garden on "Cheltenham Sand" which according to http://www.gloucestershire.gov.uk/me...ded%20appendix %20%20D.pdf is "composed of medium grained quartz sand with limestone fragments and gravel lenses" I've measured my soil pH several times with the 1 pound soil testing kits and it always comes out at slightly alkaline which is what you'd expect. Recently I bought a probe type pH meter and found: - Nowhere in my garden is alkaline according to the probe - even places that I limed in the Winter! - A lot of places have a pH of around 6. This includes a tub of erricaceous compost where a blueberry is living happily. - I've even found spots with a pH of 3.5 but a few inches away, it's a more reasonable 6. - Unused multipurpose compost has a pH of 6 - I tested the probe with plain water and got 7. A splash of orange into the water moved the reading down to 6 Anyone think anything is going wrong here? Steve Harris - Cheltenham - Real address steve AT netservs DOT com A useful bit of gardening software at http://www.netservs.com/garden/ I would tend to believe the pH meter. Take a lump of soil and mix with water -allow to settle and test the clearish liquid with the probe and then with a few drops of indicator from the test kit. Hopefully you should get the same answer from both. You should really use distilled or deionised water for the test--it is very unlikely the tap water is totally neutral (usually slightly on the alkaline side) which would be sufficient to give a false result |
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