To the uninitiated all soil seems the same, but this is far from the case. Soils have different classifications based on their composition, but soil is also classified by its pH level. Soils are generally classed as acidic or alkaline, although neutral soil is a possibility, sometimes though soil can be too acidic, making it necessary to adjust the soil’s pH level, getting closer to a neutral level.
Most plants like a soil that is the region of 6.5 through to 7 on the pH scale, this is where phosphorous and nitrogen is most widely available to plants. That being said some plants thrive in a more acidic or a more alkaline environment. It is though impossible to know what pH the soil is just by looking, and for that reason most garden centres now sell soil testing kits. These kits are simple to use and will offer a simple visualisation of the pH level.
If it is discovered that the pH level of the soil is below 6.5 it means that the soil is acidic, and may mean that it has to be made more alkaline. The most common method of making the soil less acidic is to add lime, be it a calcium compound or a compound made from calcium and magnesium. In garden centres this normally means a product that contains hydrated lime or burnt lime, although hydrated lime works quickest.
The use of lime is not without its issues, and it is easy to overdo it, causing issues not least of which is making the soil too alkaline, a problem which is much more difficult to rectify. Any application of lime has to be carefully done, and the amount to add is down to the type of soil it is being added to. In general sandy soil will require less lime added to raise the pH level, whilst peaty soils will require more lime to make the same increase.
While hydrated lime will be the quickest method of reducing the soil’s acidity level, it may require two or more months to achieve the new pH level desired. Trying to changing the acidity level too quickly is a recipe for disaster. Changing the pH level of the soil may also mean that plants that have previously thrived no longer do so well, although on the plus side it should equally mean that more plants will grow well in the garden.