The answer to 'when to irrigation installation' is that the best time to install a new irrigation system or upgrade an existing one is typically in the spring or fall. During these seasons, the weather is mild and the ground is easier to dig, which makes the installation process more efficient and less disruptive to your landscape.
Spring is an ideal time to install an irrigation system because it allows the system to be fully functional and ready for the hot, dry summer months when your lawn and garden will need the most water. Fall is also a great time, as it allows the system to be installed before the ground freezes, and it gives the landscaping time to establish itself before the next growing season.