This unit is a brief introduction to irrigation principles important to horticulturists. Proper design and operation of irrigation systems requires experience, science and art. Irrigation system design begins with a landscape plan specifying plants suitable for the available topography, soil, climate, and water. Plant species adaptable to climate and soil conditions are easier to irrigate and maintain. The following items are necessary for design and operation of irrigation system for landscapes.

• — Plant water requirements (peak demand)
• — Condition of the water and its supply
• — Soil type(s), condition and topography
• — Weather and climate information
• — Microclimate concerns
• — Irrigation scheduling constraints