Certified Professional Horticulturist (CPH) Practice Exam

What is the best method for watering plants?

1. Apply many frequent light waterings

2. Add sufficient water to soak the medium to a depth of the root zone

3. Add two inches of water per week during warm months

4. Apply one-part hygroscopic water to 2 parts capillary water

The correct answer is: Add sufficient water to soak the medium to a depth of the root zone

The best method for watering plants is to add sufficient water to soak the medium to a depth of the root zone. This approach promotes deep root growth, which is crucial for plant health and resilience. Plants need water to reach deep into the soil, allowing them to access nutrients and maintain stability. When water penetrates to the root zone, it encourages the roots to grow deep rather than staying near the surface, which makes the plants more drought-resistant and able to thrive in varying conditions. Using frequent light waterings can lead to problems such as shallow root development and increased susceptibility to stress from drought. While adding two inches of water per week during warm months might seem beneficial, it does not account for the specific needs of different plant species and their varying requirements based on soil type, climate conditions, and growth stages. The method involving applying one-part hygroscopic water to two parts capillary water is less practical and not commonly used as a standard watering practice in horticulture, as it complicates a naturally simple process.