Certified Professional Horticulturist (CPH) Practice Exam

What is the least amount of water required in a vegetable garden for optimal growth?

1. ½ inch per week

2. 1 inch per week

3. 2 inches per week

4. 3 inches per week

The correct answer is: 1 inch per week

The least amount of water required for optimal growth in a vegetable garden is generally understood to be around 1 inch per week. This amount of water helps to adequately saturate the root zone of the plants, promoting healthy growth and development. Water requirements can vary based on several factors, including the type of vegetables being grown, soil type, and climatic conditions. However, a general guideline is that most vegetable crops thrive with about 1 inch of water per week, which can come from rainfall or irrigation. This amount allows the plants to absorb enough moisture without overly saturating the soil, which could lead to root rot or other issues. Lower amounts, such as ½ inch per week, may not suffice for many vegetables, especially during warm weather when evaporation rates are higher. On the other hand, larger amounts like 2 or 3 inches per week could be excessive, potentially leading to waterlogged conditions and poor aeration in the soil, thus negatively affecting plant health. Therefore, 1 inch per week strikes a balance, ensuring that vegetable plants receive the necessary moisture for optimal growth while minimizing the risk of overwatering.