Raising and lowering pH is not an exact science and most plants have a reasonably wide pH tolerance, certainly to within 1 pH point. The long list of pH preferences below indicates that while a majority of plants can survive on a pH around 6.5, some need a particularly acid or alkaline soil. Altering pH takes time. Do not expect rapid changes. Work steadily towards giving a plant its ideal conditions.
Soil Types:
Sandy Soils: A light, coarse soil comprised of crumbling and alluvial debris. Loam Soils: A medium friable soil, consisting of a blend of coarse (sand) alluvium and fine (clay) particles mixed within fairly broad limits with a little lime and humus. Clay Soils: A heavy, clinging, impermeable soil, comprised of very fine particles with little lime and humus and tending to be waterlogged in winter and very dry in summer.
Tips on Testing:
Don‘t leave the probe in the soil longer than necessary because the metal electrodes may pit, with the possibility of damage to the meter mechanism.
Insure that the probe is wiped clean and well dried before storing in order to minimize the oxidation of the metal electrodes.
Be sure to keep the probe away from metal objects.
Use the meter only in soil. Do not place the probe into water