Concrete is lime, gypsum, cement, stone and water. It is not uncommon for concrete to release lime into the soil when new, and then much more slowly as the years go by. This could raise the Calcium as well as the ph of the soil next to the concrete. Is this a problem? Maybe if you are growing plants that require acid soil (like strawberries or raspberries) next to the blocks (though that can be mitigated with Sulfur). However, you are only dealing with thin dividers here rather than a concrete slab so any impact should be minimal. Still, this is a good reason to test the ph of your soil so you know what you are starting with.

Concrete blocks would make good. and long lasting, raised beds. There may be a small amount of lime released from new blocks and more as the blocks age but that has not been found to be much of a problem where used. Loss of organic matter has contributed to lower soil pH's than concrete blocks have contributed to raising the soil pH.

The "patio" blocks in the link you posted will not do a good job of holding back the soil, however at least in my experience.

Soil testing for soil pH is always a good idea and should be done periodically.

kimmq is kimmsr