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How to Water the Lawn After Fertilizing

Park Sprinkler image by Gary Ng from

Watering your lawn after an application of fertilizer is an important part of the feeding process. The water begins washing the nutrients down into the root zone where they will benefit the grass plants. Just as important, the water washes the fertilizer materials off of the tender grass blades and into the thatch below, reducing the concentration of the fertilizer, preventing chemical burn to the blades and brown discoloration on your lawn.

Follow each and every application of fertilizer with an irrigation session, whether the fertilizer applied is fast-release, slow-release or even diluted with water when applied. Washing the fertilizer compounds off of the blades immediately is critical.

Set a rain gauge or clean shallow can on the lawn in central location to measure the amount of water being put out by your irrigation system after fertilizing.

Irrigate sufficiently to drench the soil with at least 1/4 inch of water after each application of fertilizer. This will wash the fertilizer off of blades and wet the primary root zone without causing run-off of fertilizer onto the street, sidewalks or storm drain system.

Check the rain gauge to ensure that at least 1/4-inch, but not significantly more, water has been applied.

Mow The Lawn After Fertilizing?

Lush, green lawns take a lot of consistent maintenance to stay healthy without any unsightly brown dead spots appearing, while extreme weather, foot and pet traffic all contribute to your lawn's demise if you neglect it. In this case, you can mow directly after watering. If you use liquid fertilizer, mow after the lawn has completely dried. During the growing season, you should mow at least once a week. Mow consistently and often for the healthiest lawn. Although you need to time the mowing carefully after fertilizing, both actions work well together to improve the lawn's health.


Fertilize your lawn when the weather forecast does not include substantial amounts of rain for at least a day. Applying fertilizer before a rain will often allow the applied nutrients to be washed past the root zone where the lawn cannot benefit from them. Rain also leads more easily to fertilizer-contaminated run-off, which you need to avoid.

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