Unfortunately, there isn’t a one-schedule-fits-all when trying to figure out how often you should fertilize your lawn. A whole bunch of factors go into deciding when you should and shouldn’t pull out the fertilizer spreader. Because of this, I definitely don’t recommend following someone else’s schedule, which probably doesn’t fit your lawn and more than likely doesn’t follow your state rules. But don’t worry; in this article, I’ll show you how to put together your very own tailored fertilizing schedule.
How Often Should You Fertilize Your Lawn? (The Short Answer)
Slow-release fertilizers dissolve in about 6-8 weeks. As a result, spacing applications eight weeks apart will ensure that your lawn is provided with constant feed. Even so, a tailored fertilizing schedule for your lawn also needs to take into account the following factors.
- State & City Ordinance Rules – Allowed Fertilizing Periods
- State & City Ordinance Rules – Maximum Application Limit
- State & City Ordinance Rules – Fertilizer Specification
- Local Climate & Seasonal Variation
- Soil Test Results
Factors That May Influence How Often You Fertilize Your Lawn
When creating your fertilizing schedule, you’ll need to dig into each factor from above to get an understanding of what can and can’t be done. Plus, you’ll want to first figure out what your ultimate goal is. Let’s take a closer look at how these factors will affect you and your lawn.
State & City Ordinance Rules
Each state, county, and city has its own set of rules. These rules (City Ordinance) are put in place to protect the ecosystem within specific areas. This is the reason a schedule for New York isn’t going to be suitable for somewhere like Texas. So, let’s have a look at what these different rules might mean for you.
Allowed Fertilizing Periods
States such as Florida have restrictions in place to ban fertilizing during certain periods. The blackout for fertilizing in many Floridian cities falls during the rainy season to prevent fertilizer run-off into waterways.
Maximum Application Limit
Every state puts restrictions on how much fertilizers can be used in any given area. As an example, the state of Maine limits nitrogen to no more than 2lb per 1000ft2 per year. So, the type of fertilizer you choose to use will determine how many applications you’re allowed.
Fertilizer Specification
Many cities limit the nutrient content that we are allowed to use on our lawns and grass. These can be restrictions such as a 20% Nitrogen limit in parts of Florida and a 0% Phosphorus requirement for New York state. These restrictions, along with other ordinance limitations, define what your fertilizing schedule will look like.
Local Climate & Seasonal Variation
When you put together your fertilizing schedule, remember that you need to be flexible. Waiting for your lawn to become active and fertilizing well before the first frost are both elements that vary from year to year. So, building some flexibility into your schedule will help avoid any mishaps.
Soil Test Results
Before you dust off the fertilizer spreader, be sure to have a soil test carried out. After all, you need to know what your lawn actually wants. Once you have the results, you’ll be able to decide what product will work best for your grass type. In addition, the fertilizer specification needs to be accounted for within the application limit.
Designing a Fertilizing Schedule: An Example
Designing a fertilizing schedule certainly isn’t a five-minute process. Just gathering the information can take a while. To make things a bit clearer, I’ve collected the specifications for Sanibel Island, Florida. So, let’s have a look at what the City of Sanibel ordinance looks like.
| Location | Sanibel Island Florida |
| Total Nitrogen | 20% or less |
| Total Phosphorus | 2% or less |
| Slow Release Nitrogen | 50% or more |
| Nitrogen per 1000 Square Feet per Application | Up to 1 pound |
| Nitrogen per 1000 Square Feet per Year | Up to 4 pounds |
| Applications per Year | 6 Maximum |
| Blackout Periods | July 1 through September 30 |
Understanding the Numbers
As you can see, the City Ordinance plays a big part in your fertilizing schedule. If you use some calculations along with the city’s rules, you’ll start to see how much fertilizer to use and when to use it.
So, here’s how to work out the number of applications and how to space them out.
Option 1 – Four Applications
- 1 LB (single application) x 4 (applications) = 4LB (total per year)
- 39 Available Fertilizing Weeks
- Application 1 = Day 1
- Application 2 = Day 91
- Application 3 = Day 181
- Application 4 = Day 271
Option 2 – Six Applications
- 66 LB (single application) x 6 (applications) = 4LB (total per year)
- 39 Available Fertilizing Weeks
- Application 1 = Day 1
- Application 2 = Day 55
- Application 3 = Day 106
- Application 4 = Day 163
- Application 5 = Day 217
- Application 6 = Day 271
How Many Times to Fertilize the Lawn “Option 1 vs Option 2”
You may think that fertilizing the lawn four times is easier than six times. You would be right, but in this case, the gap between applications increases from 54 days to 90 days. The downside to this is that the slow-release nitrogen takes between 6-8 weeks to totally dissolve, and the four-application approach exceeds this period. So, if you use the 6-application approach you will have a constant nitrogen release throughout the whole of the 39 weeks period.
What a Fertilizing Schedule Might Look Like
Now that the math is out of the way, you can go ahead and enter the dates into your schedule. In this example, I’ve used the six-application method. This means I can make the most of the fertilizer’s slow-release nitrogen content.
| Month | App 1 | App 2 | App 3 | App 4 | App 5 | App 6 |
|---|---|---|---|---|---|---|
| Jan | 17th | |||||
| Feb | ||||||
| Mar | 11th | |||||
| Apr | ||||||
| May | 4th | |||||
| Jun | 27th | |||||
| Jul | X | X | X | X | X | X |
| Aug | X | X | X | X | X | X |
| Sep | X | X | X | X | X | X |
| Oct | 1st | |||||
| Nov | 24th | |||||
| Dec |
X = Blackout period in the above example
Keeping a Flexible Fertilizing Schedule
The dates above are pretty specific for how often to fertilize the lawn. Really, these dates are just flexible dates to aim for. You’ll come across several situations where you need to make adjustments, like standing water from rain or that vacation you have booked.
So, design your schedule keeping in line with what’s allowed, but remember you can move it around a bit. The upside of having these dates and sticking to the rules is that you greatly reduce the risks of under fertilizing and over-fertilizing your lawn.
Signs that You are Overfertilizing
Being flexible with how often to fertilize your lawn is important, but you must be careful not to overdo it. I know it can be tempting to spread a few extra pounds on the lawn, but you could be doing the lawn and grass a disservice. Here are a couple of things to look out for that might indicate you are over-fertilizing.
- Slow Growth
- Yellowing and Wilting of Leaves
- Browning of Leaf Tips
How You Can Tell If You Are Underfertilizing
If you are concerned that you are under-fertilizing your grass, then you can look out for several symptoms. If you notice any of these, then you will want to look back at your fertilizing schedule and make some adjustments. If you are unsure, then a soil test will give you the exact numbers and specify what you should adjust.
- Slow Growth
- Yellow-Green or Yellow Grass
- Low Grass Volume
- Problems with Disease
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