Best Time to Fertilize Your Lawn

The schedule for the application of lawn fertilizer is dependent upon the type of grass that is being grown. Cool season grasses (Fescues, Rye, Bluegrass) have a different growing cycle than the warm season grasses (Bermuda, Zoysia, Bahia, St. Augustine) and therefor need to be maintained on a different schedule.

Cool Season Grasses (Fescue, Rye Grass, Bluegrass)

The most important time for fertilization of cool season grasses is during the fall from late August through November. During this time period the grass is beginning its period of dormancy and it is critical to strengthen the root system so that a healthy plant can emerge in the Spring. The next most important time for fertilization is during the the months of May – June in the Spring. This application should be a little lighter that the fall application. The object is to promote greening and feed the roots without encouraging so much growth of the leaves that the root system becomes weakened. Too much fertilization in the Spring can actually weaken the plant and encourage the emergence of weeds during the Summer months. If a second application of fertilizer is necessary either in the Fall or Spring, it should not be accomplished sooner than 4 weeks after the first application.

Since Fall application is the most important there is an acronym that is often used to remind one of the cycle times. SON – standing for September-October-November is a useful for remembering when to fertilize. Remember that there should be at least 4 weeks between applications.

Warm Season Grasses (Bermuda, Zoysia, Bahia, St. Augustine)

Warm season grasses respond best when fertilized between early April and mid-August. Since warm season grasses grow most vigorously during the summer months it is more important for these types of grasses to be fertilized at this time as opposed to the fall like the cool season grasses. The root systems will be strengthened and depending on the type of grass the rhizomes and stolons will be encouraged to spread and propagate new growth. Here again any successive applications should be spaced at least 4 weeks apart.

At a minimum cool season grasses should be fertilized twice annually - once in the fall (the heaviest application) and again in the Spring. Successive applications can be applied depending on the quality and use of the grass being maintained.

Warm season grasses need a minimum of at least one application of fertilizer during the early growing season. Here again successive applications can be applied based on the use and quality of the lawn desired.