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.


  1. Please advise the best type of fertilizers for each time of year for cool grasses. e.g. nitrugen, phosphorous content for Spring summer and Fall

    Thanks, Dave

  2. Is it best to fertilize a yard with a large bare spot and then seed or should I seed and once grown then fertilize. My dog has killed my yard with urine and playing which has tore up the grass . . . im basicly starting over

  3. We live in the Raleigh NC area. since last fall the task of applying Potash to our Bermuda Grass has been on o ur “to-do” list . It got done today, is that ok? Or was it a major mistake???? thanks!

  4. i need to know what to do about my grass, i had a bunch of wees in my grass so we use some weed spray over most of the yard, now we have ugly brown spots everywhere. what can i do to get me a pretty green yard?

  5. David, the best way to figure that out would be to take several soil samples from different areas of your yard. You can have these analyzed at most feed stores or horticulture programs at your local college. You can then get a good idea of what type of fertilizer mix you need.

  6. my grass is really strange this year. its been really hot and a lot of rain and no sure whats growing right now or how to treat. zip code=62226

  7. We had army worms this summer and had Tru green come and treat for them.
    About a week later about Sept. 18th we had the yard aerated and seeded. It has
    been about 16 days now and I don’t see any grass coming up. How long does
    it take to seed to germate?

  8. Muhander says

    It is first week of May I am in the process of seeding. Should I use those mixes available in big stores(seeds and fertilizers?). Last year, I used those and I ended with lot more weeds that grass. This year, I just want to over seed and worry about fertilizer in fall. Would this approach work?