When To Apply 13-13-13 Fertilizer To Your Lawn? (The EXACT Time)

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Hey there, green-thumbed friend! Wondering when to apply that 13-13-13 fertilizer to your lawn? Back when I started using the fertilizer, I had a range of queries but over a period, I’ve cracked the exact time to use a 13-13-13 fertilizer on my lawn.

The optimal time to apply 13-13-13 fertilizer to a lawn is during its active growing season, which varies depending on the type of grass. For cool-season grasses, apply in spring and fall; for warm-season grasses, apply in late spring and summer.

Got more questions? I’ll break down the best times to apply this balanced fertilizer, give you a handy table of dos and don’ts, and even discuss when NOT to apply it. Let’s get your lawn looking lush and vibrant!

Understanding 13-13-13 Fertilizer

First things first, let’s understand what 13-13-13 fertilizer is. This balanced fertilizer contains equal percentages of nitrogen (N), phosphorus (P), and potassium (K). These macronutrients are crucial for the overall health and growth of your lawn. The numbers represent the ratio of each nutrient, so 13-13-13 means it contains 13% nitrogen, 13% phosphorus, and 13% potassium by weight.

Tip: Check out my articles about why your plants need nitrogen, phosphorus and potassium.

Perhaps, there are other equal percentage fertilizers like 8-8-8 and 10-10-10. However, everything is made for a purpose.

The Exact Time To Use A 13-13-13 Fertilizer

The exact time to use a 13-13-13 fertilizer largely depends on the nature of your grass. Here’s a list of grasses along with their ideal timelines.

Cool-Season Grasses: Spring and Fall

If your lawn has cool-season grasses like Kentucky bluegrass, perennial ryegrass, or fescue, you’ll want to apply 13-13-13 fertilizer during the spring and fall months when these grasses are actively growing. In general, the best time to apply is:

  • Early spring (late February to early April)
  • Fall (September to November)

Warm-Season Grasses: Late Spring and Summer

For warm-season grasses like Bermuda, Zoysia, or St. Augustine, the prime time to apply 13-13-13 fertilizer is during late spring and summer months when these grass types are actively growing. The best application periods are:

  • Late spring (late April to early June)
  • Summer (June to August)

Tricks To Apply 13-13-13 Fertilizer Effectively

Doing something for the first time is always the hardest. Based on my experience, I’ve drafted a list of dos and don’ts to help you eliminate possible errors and make the most out of a 13-13-13 fertilizing period.

Apply during active growing seasonApply during dormancy or extreme heat
Water your lawn after applicationOver-water or apply before heavy rainfall
Use a broadcast or drop spreader for even distributionApply by hand or dump in piles
Follow recommended application ratesOver-apply can lead to nutrient runoff or burning
Store unused fertilizer in a cool, dry, and safe placeMix with other chemicals or store near heat sources

Here are some other helpful articles that I wrote recently:

Looking for other ways to enhance the look and health of your lawn? Watch the video below:

When NOT to Apply and Potential Consequences

It’s essential to know when not to apply 13-13-13 fertilizer to avoid potential issues like nutrient runoff, burning, or even harming the environment.

Here are some situations when you should avoid applying fertilizer:

  • During dormancy: Fertilizing when your grass is dormant won’t provide any benefits and can lead to nutrient runoff, which can harm local waterways.
  • Extreme heat: Fertilizing during extreme heat can stress your lawn and cause burning.
  • Just before heavy rainfall: Fertilizing before heavy rain can result in nutrients being washed away, causing pollution in nearby water sources.


How much 13-13-13 fertilizer should I apply to my lawn?

The recommended application rate varies depending on the grass type and your lawn’s specific needs. In general, 10 pounds per 1,000 square feet is a common application rate.

It’s essential to follow the manufacturer’s instructions and adjust the rate based on your lawn’s needs. When in doubt, it’s better to apply less fertilizer than to over-apply.

How often should I apply 13-13-13 fertilizer to my lawn?

Generally, you should apply 13-13-13 fertilizer twice per growing season, once in the spring and once in the fall for cool-season grasses, and once in late spring and once in summer for warm-season grasses. However, this may vary depending on your lawn’s specific requirements.

Can I use 13-13-13 fertilizer on my garden plants as well?

Yes, 13-13-13 fertilizer can be used for garden plants, as it provides a balanced source of nutrients. However, different plants have different nutrient requirements, so it’s essential to research the specific needs of your plants and adjust the application rates accordingly.


The best time to apply 13-13-13 fertilizer to your lawn depends on the type of grass and the growing season. For cool-season grasses, apply in the spring and fall, while warm-season grasses benefit from applications in late spring and summer. Remember to follow the dos and don’ts mentioned above to ensure optimal results and avoid potential issues.

What’s next? Grab your gardening gloves, your spreader, and your 13-13-13 fertilizer, and let’s make your lawn the envy of the neighborhood!

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