Should You Water Lawn After Fertilizing? Why, And How Often?

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New gardeners often ask whether it is necessary to water the lawn after fertilizing. If yes, then how soon should you do it? How much should you water, and how often? You probably have the same questions, and that is why you are here!

Fertilization plays a big role in the long-term health of your lawn, and watering is a crucial part of it. The right timing and frequency come down to complete science and are more than plain guesswork.

We understand that keeping the lawn green is a struggle for many gardeners. So, in this article, we will answer all your questions and share everything you should know about watering your lawn after applying fertilizer.

Why Water Lawn After Fertilizing? Is It Important?

Watering the lawn after applying fertilizer helps to improve nutrient absorption. This is because it effectively washes the fertilizer from the grass blades into the soil. So, yes, it is crucial for your lawn’s health to water after fertilizing.

However, watering must be done correctly to ensure maximum absorption and to prevent the excess fertilizer from running off into nearby water sources such as lakes, rivers, and ponds.

While the chemicals in fertilizers are nutritious for your lawn, they are also hazardous to the water ecosystem. For example, Phosphorus and Nitrogen in fertilizers cause excessive growth of surface algae in ponds and lakes. This lowers oxygen levels in the water and prevents sunlight from reaching the depths, thereby harming marine life.

As a gardener, consider it your duty to minimize runoff by efficiently washing down the fertilizer into the soil. Ultimately, it will not only benefit your lawn’s health but will also help reduce environmental pollution.

When to Water Your Lawn After Fertilizing

First, it’s important to understand the type of fertilizer you are using, as this will determine how soon you should water your lawn afterward.

Lawn fertilizers generally come in two forms: systemic and contact. You will usually come across granular fertilizers (systemic type) or liquid fertilizers (contact type). Both types have specific guidelines when it comes to watering. Let’s take a look at these now.

Watering After Applying Granular Fertilizer:

Granular fertilizers are systemic. This means they get absorbed directly by the roots of the grass on your lawn. Therefore, you should water your lawn immediately after applying granular fertilizer to ensure maximum absorption into the soil. Make sure no granules are left on the grass blades, as they can burn the grass under sunlight.

Generally, you need to water the soil up to half an inch to effectively push the granular fertilizer into the ground. Furthermore, granular fertilizers are more prone to running off due to overwatering. So, overwatering would significantly reduce their effectiveness and increase the chances of pollution.

Granular fertilizer takes between 12 – 24 hours to get absorbed into the ground after watering. But the exact timing for absorption varies depending on the formula. Some granular fertilizers have a polymer coating that can slow absorption by up to three weeks. These are slow-acting fertilizers that provide slow but consistent nutrition to the lawn over a longer timeframe.

Watering After Applying Liquid Fertilizer:

On the other hand, liquid fertilizer is an entirely different game. It is a contact fertilizer. This means it enters through the foliage of the grass instead of the roots. Therefore, you should avoid immediate watering after application.

Experts recommend waiting up to 6 – 8 hours after applying liquid fertilizer to allow maximum absorption into the foliage. Again, the exact time for absorption varies from brand to brand. It is a good idea to refer to the instruction manual that comes with your fertilizer pack.

After maximum absorption (6 – 8 hours), evenly spray water over your lawn to wash down the dried fertilizer from the leaves. Any further delay could increase the chances of burning due to the sun’s heat.

Liquid fertilizers work best when you apply them early in the morning (between 5 AM and 9 AM) before the heat of the day reaches its max. Furthermore, it is better to apply liquid fertilizer on a cloudy day than on a sunny day.

How Often Should You Water Grass After Fertilizing?

You now know that it is crucial to water the lawn after fertilizing. But how often should you do it? Well, that depends on several factors, such as unexpected weather conditions, climate, and soil type. Let’s take a closer look at each of these.

Sandy soils need watering every two to three days since this type of soil does not hold water efficiently. If you live in a hotter climate, then it may be necessary to water every other day after applying fertilizer.

On the other hand, clay soil holds water for much longer. So, watering once a week should be sufficient. Any more than that could result in waterlogging, which can cause the grass to rot. However, too little will harden the soil, making it unfavorable to foliage.

But regardless of the type of soil, if you notice any signs of stress and dryness, it means it is time to water the lawn. You should always keep an eye out for any dull spots on your lawn, or grass curling upon itself. These are the tell-tale signs of dryness and signal immediate watering.

The frequency of watering also depends on the weather conditions. For instance, a longer monsoon season with heavier rain would require less water since the rainwater will be more than sufficient. On the other hand, a hotter than usual summer with a dry spell will require you to water more frequently.

The Do’s and Don’ts of Watering Lawn After Applying Fertilizer:


  • Always read the instruction manual that comes with your fertilizer to check for any exceptions.
  • Keep an eye on the local weather conditions and plan accordingly. Watering your lawn just before heavy rain could easily lead to over-watering.
  • Deeply water your lawn a day before applying fertilizer. However, apply the fertilizer only after the grass has thoroughly dried. Finally, water the lawn for a second time (the timing will vary depending on whether you use granular or liquid fertilizer).
  • The best time to water your lawn is between 5 AM and 9 AM before the sun comes directly overhead. This is because the rate of evaporation is lower early in the morning. Furthermore, it allows the soil more time to absorb the nutrients from the fertilizer.
  • If you use an above-ground sprinkler, such as a rotary or oscillating sprinkler, ensure you switch locations to provide proper coverage of your entire lawn.


  • Don’t water and fertilize your lawn late in the afternoon or evening. Low temperatures, high levels of humidity, and lack of sunlight can quickly cause toxic fungi to grow. This toxic fungus often spreads uncontrollably and severely damages the grass.
  • Excessive water after fertilizing can cause the nutrients to wash away. Not only does this reduce the fertilizer’s efficiency, but it can also lead to groundwater contamination. So avoid overwatering.
  • Don’t water immediately if you are using a spot-weed treatment in combination with a granular fertilizer. Wait an hour or two before watering to allow the weed treatment to dry up fully.

Frequently Asked Questions

How Much Should I Water My Lawn After Fertilizing?

You need no more than half an inch of water above surface level to wash the fertilizer into the soil. So 15 – 30 minutes of watering with a decent pressure level using a ground sprinkler should be enough.

Then 24 hours after fertilizing, deeply water the lawn to a point where the soil receives 3-4 inches of saturation. This is equivalent to around 1-2 inches of water above the surface.

After that, avoid watering again until you observe any signs of dryness. Infrequent but deep watering is the key to growing a healthy lawn with deeper roots.

How Often Should I Fertilize My Lawn?

You can fertilize your lawn up to 5 – 6 times a year if you are not using a slow-release formula. On the other hand, slow-release formulas have a timeframe ranging from two to three months. Applying a slow-release formula twice a year during the spring and early fall months is sufficient.

What is the Best Season for Fertilizing the Lawn?

It is best to fertilize your lawn around late spring and the early months of fall. However, this greatly depends on the climate in which you are living. Fertilizing the lawn a few times in the months leading to summer should be enough. Avoid over-fertilizing as it could cause serious adverse effects, especially during the hot summer months.

Should I Water the Lawn When Grasscycling?

Grasscycling is an advanced and natural form of fertilization. In this method, you leave the grass clippings where they are after mowing. This slow-release method does not require you to specifically water the lawn immediately after mowing.

However, you will have to follow your regular watering schedule. Note that grasscycling only makes up to 25% of the fertilization needs of your lawn. Nevertheless, it is still cost-effective, reduces pollution by preventing excessive fertilizer usage, and there is no chance for the grass to burn.

Can I Apply Liquid Fertilizer to Wet Grass?

Applying liquid fertilizer to wet grass can reduce its potency by up to 60% or more. This is because liquid fertilizers absorb via contact with the foliage. If the grass is soggy, the liquid fertilizer’s retention on the blades will reduce significantly, and therefore, it will run down. However, you can apply liquid fertilizer to slightly damp grass. It should work for as long as the liquid sticks to the grass blade.

Final Thoughts

In conclusion, watering after fertilizing is extremely important for the health of your lawn. Both the timing of watering and the right amount are crucial for the proper absorption of fertilizers into the soil.

But it is not that straightforward. It takes more than just guesswork to water your lawn after fertilizing. You need a well-planned watering schedule after considering factors such as the season, weather conditions, fertilizer type, soil type, and more.

Fortunately, fertilizers often come with an instruction manual, which can come in handy if you need clarification on any exceptions. So, it is a good practice to refer to the manuals occasionally. After all, slow-acting fertilizers work differently from fast-acting fertilizers. Therefore, the watering requirements also vary accordingly.

We hope to have answered all your questions about watering the lawn after applying fertilizer. For more gardening and lawn care tips, check out our related articles below.

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