Arborvitae are popular evergreens that provide year-round privacy and structure in many landscapes. Their health depends significantly on receiving the right amount of water delivered directly to the root zone, making a soaker hose an effective irrigation tool. Determining the correct run time is not a one-size-fits-all solution, as it depends on the specific flow rate of your hose and the tree’s hydration needs. Calibrating your equipment allows you to establish a precise watering schedule that promotes deep root growth and minimizes water waste.
Understanding Arborvitae Hydration Requirements
Arborvitae (genus Thuja) possess a naturally dense and shallow root system, making them susceptible to drought stress. These fine roots remain concentrated near the soil surface, where moisture evaporates quickly during warm weather. When the topsoil dries out, the plant cannot absorb sufficient water, often leading to browning or dieback of the foliage. This stress compromises the plant’s overall health and defenses.
To counteract their shallow root tendency, the watering method must encourage roots to grow deeper into the soil profile. The goal is to apply water slowly and deeply enough to soak the soil to a depth of at least 12 inches. Deep, thorough irrigation promotes a resilient root structure capable of accessing moisture reserves below the surface layer. Delivering a substantial volume of water infrequently is preferable to applying a small amount daily.
Measuring Soaker Hose Output
Calculating the watering duration requires calibrating the specific soaker hose setup, as water pressure and hose quality vary widely. The flow rate is measured by determining how long it takes to deposit a target depth of water onto the soil. A practical method involves placing several straight-sided containers, such as tuna cans, along the path of the hose near the arborvitae’s base. These containers should be spread out to capture the average output across the entire length being used.
Run the soaker hose for a measured period, such as 30 minutes, using the water pressure level you typically use for irrigation. After the time is up, use a ruler to measure the depth of water collected in each container. Average these measurements to find the mean depth of water delivered during the 30-minute test. This simple calibration step ensures your watering time is based on the actual performance of your equipment.
Calculating the Ideal Watering Duration
The standard for deep watering is to deliver the equivalent of 1 inch of water to the root zone during a single session. This volume provides the deep soak necessary to hydrate the root ball and surrounding soil. To determine the precise duration, combine this 1-inch target with the flow rate established during your calibration test. For instance, if your test showed the hose delivered 0.25 inches of water in 30 minutes, the ideal watering duration to reach 1 inch would be 120 minutes (two hours).
The frequency of deep watering depends heavily on the tree’s age. Newly planted arborvitae (the first one to two growing seasons) require more frequent attention to establish their root systems. These younger trees may need the 1-inch equivalent applied two to three times per week, depending on soil type and weather. Established trees (in the ground for three or more years) typically require the 1-inch equivalent only once per week during the active growing season.
Seasonal and Environmental Adjustments to Frequency
While the duration of the soaker hose run time is based on a fixed 1-inch application, the frequency of watering must change throughout the year. During periods of high heat, drought, or strong winds, the rate of water evaporation and transpiration increases significantly. In these conditions, you may need to increase the watering frequency to twice a week to compensate for accelerated moisture loss.
Soil type also influences watering frequency. Sandy soils drain quickly and retain less moisture, requiring more frequent application of the 1-inch soak. Clay soils hold water for longer periods, necessitating a reduced watering frequency to prevent saturation and root rot. During cooler seasons or periods of frequent rainfall, reduce the frequency to once every two weeks or less.
The most reliable method is to manually check the soil moisture before each session. Insert a finger or a moisture meter a few inches deep into the ground; if the soil feels damp, delay the next watering session.