Best Time To Fertilize Lawn Before Or After Rain: A Myth Busting Guide

Both fertilizing and watering the lawns and gardens are beneficial to ensure healthy and faster growth. But doing so excessively will bring harm only. It becomes confusing to determine whether to apply fertilizer when the rain about to happen.

So, not just you, a lot of people are trying to figure out the best time to fertilize lawn before or after rain. In this article, the mystery will be demystified so that there is no more confusion anymore.

Impact of Fertilizing Lawn Before Rain

best time to fertilize lawn before or after rain

Coordinating fertilization with weather wisely will result in a lush lawn. Applying some organic fertilizer ensures rapid and healthy growth. But the timing of applying the fertilizer is the essence here.

So, determining whether to apply fertilizer before or after the rain is crucial. To keep things simple, let’s check the benefits and problems of applying fertilizer before the rain first.

You fertilize the lawn because it needs nitrogen. The rain ensures your lawn gets enough nitrogen from the fertilizer. So, the main reason why you may want to fertilize before the heavy rain is because it will help the fertilizer to be absorbed in the oil pretty well.

Heavy rainfall before fertilization comes with some disadvantages too. It may wash away the fertilizer before it gets into the soil. As a natural consequence, it will affect the water quality in your community too.

This happens naturally and almost obviously. Any fertilizer you apply to your lawn that runs off after any heavy downpour will make its way in your local lakes, rivers, and bays.

And as you can remember, the key ingredient to such fertilizer is nitrogen. And this nitrogen will form in nitrate which will impact the water severely and endanger the health of you and your local community.

Impact of Fertilizing Lawn After The Rain

rain on lush greenery lawn

It is beneficial to fertilize after the rain too. Undoubtedly, it increases the effectiveness of the fertilizer. The potency of your applied fertilizer will be at its best when you apply after a heavy downpour.

So, it ensures the optimal growth of lawn grasses (denser too!) and you will end up with a lush greenery garden.

And more importantly, there is no chance of washing off the fertilizer from the garden. So, there is no risk of polluting the water in your community too.

But it comes with some disadvantages too. You will be losing the natural way of getting the fertilizer into the soil opportunity.

Even if you use the sprinkler or manual watering, you can’t get the appropriate coverage of your land. Unintentionally, you will skip some areas. Besides, it will take a more manual endeavor to ensure the lush greenery of your lawn.

What’s The Best Time To Fertilize Lawn Before Or After Rain? 

fertilizing the lawn after the rain

Let’s first recap what it takes to have a healthy and green lawn. It’s actually a combination of the right elements that you have to apply at the right time. This is what you need:

  • Right amount of water spread evenly throughout the lawn.
  • Proper access to the sunlight.
  • Of course, oxygen and carbon dioxide.
  • Lastly but most importantly, the roots of your plants need the right nutrients at the right time.

Just like we take vitamins and other supplements to mitigate our nutrients deficiency or ensure better growth, our lawn needs those extra boosts too. That’s why we apply fertilizer to ensure nitrogen so that the grass gets enough nutrients.

Fertilizing the lawn after the heavy rainfall is always better. Only then, there will be almost no chance of mixing fertilizer in the water. If the water in your community is polluted, you will be a victim of it directly or indirectly.

It may sound tempting to take the advantage of heavy rainfall for seamless fertilization. It undoubtedly helps to disperse the fertilizer across your lawn evenly.

But it will be an irresponsible thing to do. Let me remind you again, a polluted environment will affect you and your family.

Besides, there are other ways to get the benefits of heavy rainfall. Keep in mind that, both the excessive and less irrigation is bad for your lawn. So, you need to determine the optimum level of irrigation.

One common test to get the same advantage of rainfall is called the ‘catch-can test’. The test tells you how long you should keep the irrigation system turned on to effectively water-in fertilizer.

Through this test, you can easily determine exactly how much water your lawn is receiving. For accurate irrigation, it is a highly effective test and you should take the advantage of it.

This is how you should do it….

Get some empty tuna cans and place them around your lawn. Start watering and keep track of time and determine exactly how long it takes to fill those cans to ¼ inch. Let’s say it takes 20 minutes.

To absorb all the nutrients of your fertilizer at the root level, you need to turn on the irrigation for that 20 minutes. Anything less or more will bring harm only. And you should do this irrigation within 24 hours of applying fertilizer.

In no cases, you should not apply more than ½ inch of water to your lawn after applying fertilizer.

Fertilizing A Lawn: My Approach!

lady bug on lawn grass after heavy rain

Most of the time, rain is not my concern. In fact, it is good for any lawn owner. Of course, too much rain in a very short period of time may be concerning.

But then again, how much rain is too much largely depends on lots of factors like the thickness of the turf, slopes in the lawn, drainage ditches, and so on. All those factors will determine how much wash out your lawn can get.

I personally try to avoid fertilizing before the rain. I apply fertilizer just on time and don’t heavily depend on the rainfall. If it happens, okay. If not, I just run my sprinkler system!

I do need the water to move the granules down into the thatch. Only that way, I can prevent my applied fertilizer from getting carried away. If the rain does not work in my favor, I just run my sprinkler.


Is It Better To Fertilize Before Or After Rain?

Answer: Applying the fertilizer before the rain may result in washing away of your fertilizer and pollute the community water. The best thing to do is to water your lawn a day or two before you apply fertilizer. Then the rain won’t be able to wash away your fertilizer.

How soon after fertilizing should you water?

Answer: You can start watering your lawn immediately after applying fertilizer. However, if you apply fertilizer with weed killer, you need to wait for at least 24 hours before you water your lawn.

Will heavy rain wash away fertilizer?

Answer: Yes, the possibility is high. Of course, it depends on lots of other factors like slopes on the lawn and other factors. But, a heavy downpour will wash away your lawn if not dissolved quickly.

How much rain does it take to wash away fertilizer?

Answer: Only 6 inches of heavy rain is more than enough to wash away your fertilizer. So, it’s not good to apply fertilizer before the rain (you will never know what kind of rain it will for sure).

Does rain affect fertilizer?

Answer: Of course. It will affect either positively or negatively. A good rain will help the fertilizer to dissolve better and evenly throughout the lawn. But a heavy rainfall also may wash away the fertilizer and result in loss of money and time. Also, the nitrogen in the fertilizer will turn into nitrate when mixed with rain water and will contaminate the water of your local lake and river.


As you have seen, determining the best time to fertilize lawn before or after rain totally depends on how you see it.

If you are confident your fertilizer won’t wash away due to the rain, you can go forwarding fertilizing your lawn before the rain. I just like to do it after the rain and I use my sprinkler!

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