Certified Professional Horticulturist (CPH) Practice Exam

Which method is best for determining soil pH?

1. Visual inspection

2. Smell test

3. Chemical testing kit

4. Burning a soil sample

The correct answer is: Chemical testing kit

The most effective method for determining soil pH is through the use of a chemical testing kit. This approach typically involves mixing a soil sample with a specific solution that reacts with the acidity or alkalinity of the soil to produce a measurable pH value. These kits are designed to provide accurate and reliable results, making them a standard practice in horticulture and agriculture. Visual inspection, while useful for assessing soil texture or organic matter, does not provide precise information about pH levels. Similarly, the smell test is not a scientifically valid method for gauging soil acidity, as the presence of certain odors can result from various factors unrelated to pH. Burning a soil sample is also not appropriate; it can damage the soil and does not yield any practical information regarding its pH. Therefore, the chemical testing kit stands out as the most accurate and practical choice for determining soil pH.