People who grow in containers with potting mix\soil typically need to (or should) add dolomitic\calcitic lime (never hydrated or slaked lime) prior to planting. Notice how many times sphagnum\peat is mentioned in this thread. It is a very common amendment in industry due to its characteristics. Not only is it found in the great majority of commercial potting mixes, but is also used in composting\vermicomposting. Sphagnum peat tends to harbor a lot of reserve acidity. Newer brands contain coco coir and it is also popular for amending, also has a slightly acid pH. Along with the other amendments and fertilizers that tend to be used (including manures and compost).
The lime neutralizes acidity over time while supplying Ca and Mg. It will never lower pH; it neutralizes acidity. This is especially important for container growers who use rain, distilled, bottled, RO\filtered water that lacks minerals and more acidic nutrients. If you use hard tap water for your plants, it may already have an elevated pH due to dissolved calcium and magnesium carbonates.