Turf grass is highly responsive to applied nutrients, therefore even application is a critical factor in their use. Inconsistent application can leave you with an expanse of lawn that appears splotchy or even striped, belying where the fertilizer was and was not applied. There are a bevy of tools and methods to help you accomplish this task as well as the old, low-tech standby, hand casting.
Hand casting is the low tech, low cost but effective way to distribute fertilizer over a small area of lawn. Best done with gloved hands, the appropriate amount of fertilizer for the area is measured and cast over the lawn using a smooth to and fro flicking motion. The person making the application walks across the lawn in even rows at a steady pace until the area is covered.
Drop spreaders are most commonly metal or plastic hoppers on wheels with handles that are either push or pulled across the surface of the lawn. The can be engine driven or entirely manual. At the bottom of the hopper is an aperture that can be adjusted to control the flow of fertilizer out of the hopper. The operator walks the spreader at a steady pace over the lawn in slightly overlapping rows to distribute the fertilizer at the recommended rate.
Broadcast spreaders can be manual or motorized, wheeled tools that are pushed or pulled over the surface of the lawn. The have a large metal or plastic hopper, but unlike drop spreaders--which deposit the fertilizer almost directly beneath the tool--have a section wheel that throws the fertilizer from the tool at some distance. This can help cover large swaths of grass more quickly and some models can be adjusted for the distance the fertilizer is spread.
Liquid fertilizers or water soluble fertilizer crystals that dissolve immediately and entirely when wet can be sprayed onto lawn grass directly. A sprayer or garden hose are the two common means. Hose attachments that mix the fertilizer with water has the built in efficiency of combining two tasks, fertilizing and watering, but it also prevent animals and small children from coming into contact with or consuming potentially deadly fertilizer pellets or grains left on or in the lawn. There are a number of brands on the market that sell a hose sprayer attachment pre-filled with liquid or powder fertilizer or the attachment can be purchased alone and filled with the appropriate fertilizer by the operator with each use. Commercial farmers use sprayer attachments on heavy industrial machinery to cover large acreages or for frequent applications.