Certified Professional Horticulturist (CPH) Practice Exam

Which of the following landscape features traditionally requires the most frequent irrigation?

1. Lawns

2. Vegetable gardens

3. Trees

4. Flower seeds

The correct answer is: Lawns

Lawns typically require the most frequent irrigation among the options listed. This is primarily because grass, which constitutes most lawns, has a high demand for moisture to maintain its health and aesthetic appeal. The roots of grass plants are shallow, making them more vulnerable to drought stress compared to deeper-rooted plants like trees. Frequent watering is essential for establishing a lush, green lawn, especially during warmer months or in dry climates. Lawns also often cover expansive areas, which further increases the total amount of water necessary to keep them healthy. Establishing and maintaining a lawn involves regular watering practices to ensure that the grass receives adequate moisture, particularly during germination and the growing season. While vegetable gardens also require regular irrigation, especially during warmer weather and for seedling establishment, they generally can be watered less frequently as many vegetables have adapted root systems that can access deeper moisture. Trees, once established, tend to require less frequent watering because their roots can reach deeper underground for moisture. Flower seeds may require consistent moisture during germination, but once established, flowering plants often need less frequent irrigation compared to lawns. Thus, the frequency of irrigation for lawns surpasses that of the other features listed.