The nice thing about drip irrigation is that you can start small and expand as you wish. Start with an inexpensive kit that simply connects to a spigot near your garden. Add a battery-operated timer to automatically turn the water on and off.     Drip irrigation is a good way to reduce diseases in gardens. Fungi and diseases often thrive on wet leaves, but with micro irrigation the water is delivered only to the plant’s base. The leaves never get wet and diseases don’t get started.