When it comes to maintaining organic gardening soil, the main thing to check for is pH level. The pH spectrum ranges from 0 to 14. A pH of 7 is considered neutral while 0 is totally acidic and 14 is totally alkaline (basic). Soil testing is important since certain plants prefer a bit of an acid or alkaline environment to grow. The pH level of organic gardening soil changes due to certain conditions and therefore needs to be monitored regularly.

Most food-bearing plants prefer a soil that is just slightly acidic in the range of 6.3 to 6.8. Crops such as potatoes and strawberries thrive in even more acidic conditions. Plants such as blueberries and cranberries need a soil as acidic as 4.5 to 5.0 in order to grow. Few food crops require a basic soil with a reading of over 7.0, but some flowers such as lilacs can flourish in even a chalky soil.

The main thing that affects soil pH levels is rainfall. Rain drives away basic elements magnesium and calcium while replacing them with the acidic elements aluminum and iron. Heavy rainfall creates a more acidic soil, so soil pH levels should be checked following a heavy rainfall or long drought.

To increase or decrease the pH level of your soil organically, there are various elements you can use. Nitrogen and phosphorous, which are common ingredients in organic gardening fertilizers, increase a soil’s pH level. Other elements that work in this way include calcium, lime and magnesium. In the event that you need to increase the acidity (decrease the pH level) of your organic gardening soil (not uncommon in times of heavy drought), metals such as copper, iron, aluminum, manganese, zinc and cobalt are useful. Symptoms of a soil that is too basic are the yellowing of leaves. This is a sign of a nutrient deficiency which calls for lowering the soil’s pH level.