Colorado’s semi-arid climate, characterized by high altitude and low humidity, requires careful management of water resources for lawn care. Timing the start of spring irrigation is important; starting too early wastes water, while waiting too long can damage turf after a dry winter. The goal is to apply water precisely when the grass exits winter dormancy, promoting deep root growth and ensuring a healthy start to the growing season. This decision should be based on observable conditions rather than a fixed calendar date.
Determining the Optimal Start Time
The most reliable indicator for starting irrigation is the soil temperature, not the air temperature or the calendar date. Grass roots remain dormant until the soil consistently warms up. This typically occurs when the temperature at a depth of two to three inches reaches approximately \(50^\circ \text{F}\). This thermal threshold signals that the grass is ready to absorb water and begin active growth, usually falling between mid-April and early May in Colorado.
Applying water before the soil reaches this temperature is ineffective and counterproductive for lawn health. Cold, saturated soil increases the risk of turf diseases, such as snow mold, and encourages the growth of cool-season weeds. Wait until the topsoil is visually dry and all residual snowmelt has fully dissipated. If you meet significant resistance when pushing a screwdriver six inches into the soil, it indicates a lack of moisture and confirms the need to begin watering.
Regional Considerations Across Colorado
The timing for spring watering varies significantly across the state due to Colorado’s diverse topography and microclimates. The high elevation and persistent snowpack of the Mountain Areas and High Country necessitate a later start compared to the eastern plains. Lawns in these colder zones may not reach the \(50^\circ \text{F}\) soil temperature threshold until late May or early June.
The Front Range, including Denver Metro and Colorado Springs, typically experiences earlier springs, allowing for a start in late March or early April if conditions are met. These areas experience frequent freeze-thaw cycles, requiring careful timing to avoid refreezing in pipes or damaging the sprinkler system. The Western Slope, with its arid climate, often requires earlier attention due to persistent winter dryness. Property owners in all regions must prioritize deep, infrequent watering during the shoulder seasons to prevent winter desiccation.
Initial Watering Strategy and System Preparation
Before watering, the irrigation system must be thoroughly inspected and prepared for the season, a process often called “spring activation.” This involves slowly turning the water back on to pressurize the system. Check all zones for potential damage from winter freezing, including leaks, broken sprinkler heads, or misaligned spray patterns. Repairing these issues immediately avoids significant water waste and ensures compliance with local regulations.
The initial waterings are meant to gently rehydrate the dormant turf, not stimulate immediate, aggressive growth. This is best accomplished using the “cycle and soak” method. This method breaks up the total watering time into two or three shorter intervals separated by a rest period. This technique allows the clay-heavy Colorado soils to absorb the moisture without runoff, ensuring deep water penetration to the root zone.
Once the main growing season begins, typically around May 1st, local water restrictions will dictate the schedule. These rules commonly prohibit watering during the hottest part of the day, between 10 a.m. and 6 p.m., and limit irrigation to a maximum of two or three days per week. Adhering to these municipal guidelines is mandatory for conservation efforts and helps manage peak demand on the public water system.