Certified Professional Horticulturist (CPH) Practice Exam

Which growing requirements differ between plants grown in containers and those in landscape?

1. Light, temperature, and humidity

2. Fertilizer, light, and climate

3. Temperature, watering, and hardiness zone

4. Fertilizer, watering, growing media

The correct answer is: Fertilizer, watering, growing media

Container-grown plants and those planted in the landscape have distinct growing requirements, particularly in terms of fertilizer, watering, and growing media. Fertilizer needs differ primarily because container plants are entirely dependent on the nutrients supplied in their potting mix. The nutrients can quickly become depleted due to leaching and limited soil volume, meaning these plants often require more frequent fertilization compared to landscape plants, which can access a larger volume of soil rich in native nutrients. Watering is another critical distinction. Container plants typically dry out much faster than those in the ground due to increased exposure to air and the limited soil volume. This necessitates more regular monitoring and watering schedules for container plants, while landscape plants may be more resilient and able to draw water from a larger area of soil, adapting their needs based on rainfall and surrounding conditions. Lastly, growing media plays a vital role in the care of container plants. Unlike landscape plants, which thrive in the native soil, container plants rely on specific potting mixes designed to provide adequate drainage, aeration, and moisture retention. This is crucial since the performance and health of container plants are heavily influenced by the composition of the growing media. Thus, the requirements of fertilizer, watering, and growing media reflect the unique conditions faced