When water flows backward through the water supply system, it is called backsiphonage or backflow. When that water is accidentally mixed with hazardous chemicals or bacteria, it is called dangerous! For this reason, never use spray attachments without a backflow prevention device. The chemicals used on your lawn are toxic and can be fatal if ingested.
Exterior lighting is one of the best places to use CFLs (compact fluorescent lamps) because of their long life. If you live in a cold climate, be sure to buy a lamp with a cold-weather ballast