When to Fertilize Your Lawn

When to Fertilize Your Lawn

Knowing when to fertilize makes a big difference in how healthy your lawn stays throughout the year. Of course, every part of the country is different, so the tried and true timing we use in central Florida doesn’t work for everyone. Nor does the same fertilizer, for that matter. To get a broader scope, we teamed up with Dr. Raymond Snyder, Director of Agronomy at Harrell’s Fertilizer.


10-Second Summary

  • Initial fertilizer goes down in early Spring after the last frost. Florida can be as early as February.
  • A second application comes in May for Southern states.
  • Florida and South Texas need a third application in late September/early October
  • If you do your third application in September, you can reinforce it with a fourth in November, but this one isn’t as critical.

Understanding the Numbers on the Bag

If you’ve shopped for fertilizer for your lawn, you know about the numbers. Those perplexing triple numbers that mean…what exactly? It’s not that hard, actually. Here’s what you need to know:

Nitrogen – Phosphorous – Potassium

Yep. That’s all they mean. But interpreting the numbers—that’s where the science comes in!

Your lawn isn’t smart—it just needs to eat. It eats these three elements and thrives when you do it right. A bag with a 28-0-3 designation has 28 percent nitrogen, 0 percent phosphate, and 3 percent potassium. The rest is just filler that gives you something to spread around and helps everything scatter and absorb.

Pro Tip: If you want to remember what the numbers signify, remember the acronym NPK—or “No Problem, Kenny!” Well…at least it works for me!

When to Do Your Initial Lawn Fertilizing

For most of the country, you’re going to put down that initial fertilizer after the last frost of the year. That’s probably between March and April most years.

For those of us in sunny Florida, frost isn’t exactly a guarantee. Starting in central Florida and moving South, it’s hit or miss if it will reach 32º at all. If that sounds like you, put your first fertilizer of the year down in February, closer to the end the further North you are.

For this round, you want something with around 1/2 to 1 pound of nitrogen per 1,000 square feet. That helps growth and strengthens the lawn for the growing season. Make sure you’ve mowed your grass at least once or twice before applying.

multiple applications

Prepping for Summer

If you’re in the Southern United States, you get to fertilize more than once a year for the best results. You have an optional second application in May. For Floridians, it’s a little less optional.


Generally speaking, plan on doing the second application if you’re having a warmer than normal spring in the South.

Most local home improvement stores also have recommended regiments you can follow for year-round fertilizer. Often, these are given by season as opposed to the more traditional three-number system.

Third Time’s a Charm

In the Deep South, mainly Florida and Southern Texas, plan on putting another application down in September or October. Unlike the May treatment, this should be part of your lawn care plan every year.

When to Fertilize Your Lawn

Only Fertilize the Fourth Time if You Live in the South

For those same areas in Florida and South Texas, you might want to go with a November fertilizing as well. This one is optional and we’d recommend it if the early season cold fronts are staying North of you.

If you’re going to use the November application, do your third treatment in September rather than October to give it some time between.

Now that you know when to fertilize your lawn, start making your plans now before that Winter snow turns into Spring rain!

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