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The influence of pH
Put simply, pH is a measure of the acidity or alkalinity on a scale of 1 to 14. A reading of 7 is deemed to be neutral, alkaline if above and acidic if below. The following diagram gives an idea of pH values for a range of commonly found liquids.
pH values for commonly used liquids.
pH battery acid <1 vinegar <3 acidic orange juice >4 boric acid 5 milk <7 pure water 7 neutral blood >7 sea water 8 borax >9 ammonia >11 alkaline bleach >12 lye <14
The pH value of soil, as a general rule, ranges from about 4,0 to about 8,5. An azalea, for instance, enjoys a pH of between 4,5 and 5,5 . At pH 4,5 or less, there is damage to root membranes and less favourable conditions for growth of beneficial bacteria.
Optimum pH values for some other plants:
- Camelias 5,5 to 6,5
- Gardenias ±6,0
- Magnolias 6,5 to 7,0
- Hydrangeas 4,5 to 6,0 ( the lower value gives a blue colour, the higher value gives a pink colour.)
