Efficiently watering plants
The goal is to have an irrigation system that maximizes efficiency by watering the right amount, at the right frequency, to the right place, at the right time.
- The amount is determined by the size of the plants in the hydrozone. The entire root ball area should be wet. Low and very-low use plants require less water overall, because they need less frequent irrigation. However, they still require their root ball to be soaked when they are watered.
- The frequency will be influenced by the ability of water to move through the soil and the water needs of the plants. For low water use plants, it is usually once every three weeks, for very-low plants, a few times per summer. All soils must have time between watering to allow water to drain and oxygen to reach roots. Clay soils will hold water for even longer, so frequency will be reduced to allow them to drain.
- The place is to the root zone where runoff and evaporation can be minimized. Larger plants will have larger root zones and may require a larger irrigated area. It is also beneficial to water deep. This helps to promote deep, drought-tolerant root growth.
- The right time is usually between 2:00 a.m. and 6:00 a.m. This will reduce evaporation, but still prevent conditions that are conducive to pest and disease growth. Irrigation should also be adjusted according to weather conditions. Often landscapes won’t need any winter irrigation at all.
A smart irrigation controller is highly recommended. Once set up, it can automatically adjust irrigation seasonally, increasing efficiency and paying for itself in water savings. Look for one with the EPA WaterSense label.
Compatible, complimentary plant communities can be established by grouping plants that have similar water needs into hydro-zones. When possible, re-use existing irrigation systems and retrofit them for increased efficiency.