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 MAINTAINING YOUR PLANTS: pH
pH is the scale for acid/alkaline caused by H⁺ ions, and that is crucial for the roots of our plants. It is a vital parameter, controlling their ability to obtain Nutrition. pH is measured with a affordable meter, and should be checked, not only in the Soil but also on the Watering Water. Where the tap/well/rain water might be slightly off, the nutrition we add alters it even more.

pH is another important factor. It has a significant effect on the plants’ ability to absorb the vital nutrition. Different plants have evolved to cope with different levels of pH. At the same time, many species have specialized into rather narrow ranges, and will not be able to survive outside their preferred ranges. Adding acid or a alkaline liquid to the fertilizer can control the pH of the water. The pH of the soil must be considered. For soils with buffering effect, it will be more difficult to change pH - more about that in Soil.

In general plants thrive in around pH 6-7, but it is very species specific. Here, a look at the plant’s natural habitat is a really good indicator of its preference. In general, organic matter makes soils more acid (pH less than 7), and mineral rich soils tend to be alkaline (pH higher than 7).
Succulents tend to grow under mineral rich conditions with little organic matter. This means that they in general are adapted to a relatively high pH, around 6,5 to 7,5. 

Some years ago, I analysed the soil of a range of terrestrial orchid species, in a recently restored gravel pit. The small meadow contained six species, five were only found in several small colonies of a few square meters, while the sixth occurred everywhere. Each of the five species occurred only in an area with a pH within +/- 0,15pH, and they each had their own range. It was clear to me; the pH was the main reason for the species’ distributions.
Many growers have neglected this, and I think a lot of plants have been lost due to wrong pH.
Measure it, both in the watering water, but also in the soil from time to time, using the same method as measuring conductivity.

Adjusting pH is not that hard. If the soil is too acid, you add calcium-carbonate, CaCO₃. If it is too alkaline, you can add sphagnum or water with acid water, using sulphuric acid.
Only if you have a soil that works like a buffer, it can be tricky.

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