Soil pH is important for best plant health, whether the plants are vegetables, herbs, flowers, shrubs, lawns, or trees. The chart below shows how pH affects this availability. A pH higher than 7 is alkaline and pH less than 7 is acidic. The numbers are on a logarithmic scale. For example, pH 6 is 10 times more acidic than pH 7, and pH 5 is 100 times more acidic than pH 7. This relationship also holds true for the alkaline side of the scale.
Figure 1. Nutrient availability and microbial activity as affected by soil pH; the wider the band, the greater the availability or activity. (Adapted from Truog, USDA Yearbook of Agriculture 1943-1047)
Overall, native Kansas City soils have a near neutral pH (7), so generally speaking we do not need to change the pH with lime (raises pH) or sulfur/sulfate (lowers pH) materials. Of course there are exceptions in disturbed soils due to construction, plants that respond to more acidic soils (blueberries, hydrangeas, rhododendrons, azaleas) or other factors. If you have a concern, Soil Service Garden Center has pH test kits in stock that you can use to determine if you need further testing thru your state extension office.
Your County Extension Service can provide information about soil samples. After you get the results, Soil Service Garden Center would be glad to interpret them and offer suggestions on how to correct your soil for best plant health.
105 E. 5th Street
Kansas City, MO 64106
11811 S. Sunset Drive
Olathe, Kansas 66061-7057