Weird pH readings

Discussion in 'Soils, Fertilizers and Composting' started by Chungii V, Nov 28, 2008.

  1. Chungii V

    Chungii V Active Member

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    I am wondering if anyone can explain what's causing the strange pH readings I have in a relatively new garden. The bed is about 12mths old and I've put a pond in it because of the issues with pH. I first noticed that most things I planted into this bed would very quickly produce very yellow fresh growth and not grow very well. It didn't matter what it was (acid lover or not). Everything else in my yard just seems to take off as soon as the plant is put into the ground except this one spot. Nothing had ever been planted there before although I've heard that there was originally (at least 20 years ago) a sugar cane farm in the area where we live.
    The thing with this spot though is that in a 30 cm square my readings would be from 4 up to 8.5 pH. (Yes I do know what I'm doing and I used 2 test kits to make sure it wasn't that). I have never seen this and it's like that throughout a 1.5m X 3m garden bed. I took a lot of samples because I couldn't figure it out.
    I have now got a Dracena marginata, a Kniphofia, Cordyline, Euphorbia pulcherrima, Dianella and Liriope grasses doing well in this bed (with the pond in the middle where the biggest variances were) so I have worked around the problem (I also dug in some lime to try help get a balance).
    The bed is close to a concrete slab back porch but the house is about 15 years old so this shouldn't really be relevant, plus the fact that the pH readings went like that a good 2m out from the slab before stabilizing.
    It's no longer really a problem as I have adapted my gardening to that spot but it still interests me to know why I got such extreme readings? Any ideas?
     
  2. growing4it

    growing4it Active Member 10 Years

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    That is strange. Have you you taken a soil sample and had it tested? It would likely help you know what is in your soil.
     
  3. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Probably find that the builders who built the house dumped various stuff there.
     
  4. Chungii V

    Chungii V Active Member

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    Must've been good stuff to last that long!
     
  5. kungfoogrip

    kungfoogrip Member

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    It may be possible that a previous owner may have had a hot tum or pool and either backflushed the filter or drained in in that location. I have dealt with something similar before. PH is only part of the picture. Have a soil test done if you really want to get to the root of the problem. Soil analysis will provide you witha breakdown of what nutrients are present in the soil and at what levels. It may be that there is a toxicity problem (or other imbalance). Good luck!
     
  6. bertoli55

    bertoli55 Active Member 10 Years

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    Hi, if your place was previously a cane farm there could be a range of stuff in the soil. I'm not sure what chemicals were used on cane but there would also have been places on the property where other farm business was done -vehicle maintenance, chemical storage, stables for animals etc. Quite often in times gone by, burial was the favoured way of disposing of stuff.
    We found layers of car batteries buried in a lane next door to our property (about half a metre down), noone knew about them. Also in many places around founderies etc there are a lot of heavy metals in the soil.

    We had to remove a whole pile of soil around the batteries and in other parts of our yard. If soil removal is not an option and if testing your soil for toxins is too expensive maybe for a while you could try growing plants which are known to assist in removing toxins. There are several sites which have info on this for example:
    http://www.mhhe.com/biosci/pae/botany/botany_map/articles/article_10.html
    ciao bertoli
     
  7. bertoli55

    bertoli55 Active Member 10 Years

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  8. Chungii V

    Chungii V Active Member

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    I didn't think of that and yeah I've done a bit of farm work and methods of chemical and other disposal are rather questionable.
    Also just remembered a friend once telling me how they used to mix up Dieldrin in buckets and fill holes before planting. They used to live up north and bad termite problems and at the time that was common practice.
     
    Last edited: Dec 11, 2008
  9. abgardeneer

    abgardeneer Active Member

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    Is your pond made of concrete? If so, leaching out could certainly contribute to alkaline pH measurements... until there has been enough time and water flow through the soil to balance things out.
     

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