Lawn fertilizer is essential for good lawn growth. Depending on the type of grass, fertilizer applications should be made during the growing season. Cheap fertilizers are usually water soluble, thus, have a high potential to burn the grass. Water-soluble fertilizers will give a response for four to six weeks.

Many of these rotary tiller fertilizers have disclaimers on the bag stating. They will not burn the grass if the user follows the directions. The directions usually state that the fertilizer must be watered immediately after spreading. Because these fertilizers are water-soluble, they become available in the spring when temperatures are still low.

More expensive fertilizers are not water-soluble. They have low burn potential, and give a response for up to eight weeks. These fertilizer spreaders rely on microorganisms in the soil to release the nutrients. Since the microorganisms are not active when the soil is cool, the fertilizers will not become available early in the spring.

Spreading fertilizer by hand will always cause some spots to be over-fertilized. When using a spreader, be sure to get complete coverage of the lawn. Any missed spots will appear quite yellow. Most lawn fertilizers are packaged so that the right amount of nutrients is applied per 1,000 square feet. Generally, about one pound of actual nitrogen is required for each fertilization.

Do not fill the spreader when it is sitting on the lawn. Fertilizer spills are inevitable. Spilling water-soluble fertilizer causes a large dead spot that persists for weeks. Begin applying the fertilizer by making strips around the border of the lawn. Then start at one edge and go back and forth across the lawn. Make sure each strip overlaps the previous strip. Turn off the spreader when the header strip is reached. Do not turn the spreader while fertilizer is dropping through onto the grass. Such corners are over-fertilized and the grass could be burned.

Use caution when applying fertilizer combined with herbicide, especially with broadcast spreaders. These spreaders can throw the material into flowerbeds where the herbicide can injure desirable ornamental plants, or tree and shrub roots can pick these up from under lawns.