It is Wise to Water Longer and Deeper and Less Frequently
Green Thumb Nursery, Ventura
One of the keys to plant growth lies with the roots. Plant roots always grow where there is water. If you want a plant to be stronger, have better anchorage in the soil, and be better able to survive drought conditions, then it is wise to water longer and deeper and less frequently. Conversely if you water more frequently, the plant will demand more water, more often because the roots are shallower and dry out more quickly. By watering longer and less frequently, the water reservoir will be deeper hence the plant will not dry out as fast. Most times watering deeply involves having a slow spray or low volume of water over a longer period of time.
Established landscape plants such as trees and shrubs require deep watering in areas that receive no rainfall during the dry season. This practice should normally be performed once per month. By watering slower and deeper the likelihood of erosion occurring is lessened or made non-existent.
It is best to do any watering during the time of day when the humidity is the highest and the temperature is the coolest. By watering in the early morning plants will use water more effectively because there is less evapotranspiration (water loss through the soil and the leaves). Another favored time if the early morning is not feasible is during the mid to late evening. It is wise to check your irrigation timers occasionally (during power outages, surges, time changes, and weather changes) to ensure they are operating during the times mentioned above. An important concept to understand when you are watering is microclimates. Landscaped areas in the shade, north, or east side are usually cooler and take longer to dry out and therefore do not require as much or as often watering. Areas on the south, west, or hot dry sunny areas require more attention to watering. Plants near a hot wall or pavement dry out faster than other areas. Plants near air conditioner systems dry out more quickly as well. Landscaped areas on the top of a slope are hotter and dry out more quickly than on the bottom of a slope. Windy areas are more problematic for drying out than wind-protected areas. We encourage you to become familiar with these microclimates in your own landscape, because not all plants need water at the same time. When watering, water the plants that absolutely need it (spot watering) so that you are practicing the most efficient methods of maintaining your gardens during a drought.