The soil pH is a very important factor in gardening. Soil acidity or alkalinity directly affects plant growth. If the soil is too sweet (alkaline) or too sour (acidic), plants cannot take in the nutrients like nitrogen (N), phosphorus (P), and potassium (K). Plants need specific amounts of nutrients to grow - just like we need vitamins, proteins and carbohydrates to grow, and thrive and fight off disease and stress.
The optimum pH range for most plants is between 6 and 7.5, however many plants have adapted to thrive at pH values outside this range. Most home garden plants prefer soil that is slightly acidic around 6 - 6.5, however, there are a few exceptions where certain plants prefer an acidic or alkaline soils. But fortunately, most plants are forgiving and usually will be happy as long as the pH reading is close.