Should I Weed and Feed Before or After Mowing?

Last Updated on January 16, 2023 by Grow with Bovees

Weed and feed application using a drop spreader or a broadcast spreader is a great way of controlling different types of weed found between blades of grass, while boosting the grass with the nutrition it needs to thrive and remain a lush green strong turf.

This broadleaf weed control contains both a fertilizer and herbicides that target broadleaf weeds, and they are great to use in order to keep a healthy lawn.

You should not cut the lawn any later than 24 hours before the application, and you should generally not mow for 48 hours after applying the treatment.

You will find that there are different products that prevent weeds on the market, and each come with their own instructions, making it very important to follow the direction of each product you choose to purchase and use on your grass. Make sure you purchase the correct product for your grass species.

You might not know this, but your mowing timing — much like your watering timing — plays a vital role in how efficient this product will be.

In this article we will cover all you need to know about mowing your lawn when planning on treating your lawn with a weed and feed fertilizer.

Types of Lawn Fertilizer & Weed Killer Products

There are two main types of weed and feed. One contains post-emergent herbicides — used on existing weeds — while the other type contains pre-emergent herbicides. One will typically find them under the name turf builder with weed control. The different forms are granular and liquid weed and feed.

Use a post-emergent weed and feed on already established weeds and a pre-emergent weed killer to prevent a weed problem, stopping it before seeds germinate.

You can use drop spreaders or broadcast spreaders — depending on your lawn and where you want the product — to distribute weed and feed across your turf.

When to Apply Treatment For a Healthy Lawn

Products containing post-emergent herbicide should ideally be applied to the lawn in the morning.

If you are dealing with warm-season grasses, it is best to apply weed and seed during early spring, at the start of the growing season.

This does not need to spread over your entire lawn but only on the spots where weeds are present. Use regular fertilizer for the healthy parts of the lawn.

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Recently planted grass seeds or new lawns should not be treated with weed and feed immediately.

The best time of year to apply weed and feed will depend upon several factors.

Do You Mow the Lawn After or Before Applying Weed and Feed?

Let us have a closer look at when it is appropriate to mow your lawn if you are planning on applying weed and feed herbicide treatment to your lawn.

Mowing Before You Apply Weed & Feed

When planning to treat your lawn with weed and feed to rid it of broadleaf weeds, it is recommended that you do not mow your lawn right before the treatment.

By right before, we mean within 24hrs of application.

Although the fertilization part of the weed and feed will most probably not be affected, the herbicidal part of it will. Mowing weeds means that there is less leaf surface area on the weed leaves for the product to enter the leaves, impairing its ability to kill broadleaf weeds.

To spread weed and feed over a larger foliage surface area is better.

If you mow your lawn right before weed and feed application, you may also run the risk of your healthy grass blades getting burned and damaged, as the lawn surface is already wounded and in distress.

Trimming the grass a few days before applying the lawn treatment is more ideal, as it gives the leaves a chance to recuperate and grow longer.

Mowing After Weed & Feed Application

Now that you have applied the fertilizer and weed control, it is crucial that you do not mow your lawn straight away. It is recommended to wait up to 48 hours before trimming grass after a weed control treatment.

Roughly two days is the time needed for the herbicide to penetrate the leaf blades and start doing its work. Mowing before this may impair the product from working to its full potential.

How Short or How High To Mow Grass After Applying Weed and Feed?

The mowing height of your grass also plays a role when wanting to treat your lawn with a weed and feed product. It can help fight lawn weeds but only if a careful balance is maintained between mowing too short and too long.

Mowing Too Short:

You have now treated your grass lawn with weed and seed and waited the recommended two-day period. The grass is now ready to be trimmed. Be aware that you do not trim the blades too short.

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Leaf blades that have been cut too short are more vulnerable to weather changes — especially the summer heat and cold of winter — and weed invasions. Root growth and development can also be impaired.

Mowing Too Long:

Leaving your grass too long after or before the application of weed and feed products is also not the ideal thing to do.

When the grass blades are too long, the added wait of a weed and feed product may way down the leaves making them cover up surrounding grass blades.

This may end up suffocating them and causing yellow or brown spots.

Another reason to not treat your lawn when it is too long is, if the lawn is too dense, the product may have a hard time reaching the weeds properly.

Apart from the above reasons, keeping the lawn too long is not great in general. Tall grass does not look appealing as it may look rough or uneven and dense lawn traps moisture which means that your lawn will be more susceptible to fungal infection as well as other lawn diseases.

Should Lawn Clippings Be Bagged And Used After Weed and Feed?

Whether you should be bagging your clipped grass blades after mowing and lawn treatment depends on how severely your grass was infested by invasive weeds.

If broadleaf weed growth is a big problem in your lawn, it is advised that you bag your clippings after mowing the lawn.

Doing this before applying weed and feed granules will reduce the risk of weed seeds spreading, preventing a more severe weed infestation.

If you mow after treatment, it is in order to leave the lawn clippings on the ground until you mow your lawn again. This way, the leftover product granules of the weed and feed will be redistributed and have more time to work if it has not properly broken down yet.

Making Compost With Herbicide Treated Clippings

We do not recommend that you use bagged and treated clippings for compost straight away, as the chemicals of the herbicide not only kill weeds but can hinder seeds from germinating.

You can, however, treat it so that it becomes usable. Usually compost heaps are treated with bacteria. They will not help with herbicides. If you use grass clippings that are covered in weed and feed products, you need to use a fungus to treat them if you want to use them on your compost heap.

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Fungi can help break down herbicides and transform toxic clippings into usable ones.


You will see on the packaging of the product how often you should water after and before treatment. It is an important aspect to consider.

Some products work better in rather dry conditions, whereas others need water the morning before application so that the granules stick to the leaves of weed, and you should therefore apply it to a wet lawn — in this case morning dew or trickles from a sprinkler system will also do the trick.

Watering correctly is just as important as timely mowing when it comes to applying weed and feed to your yard.

In general, it is recommended to water only a couple of days after application of the treatment. Watering the lawn after weed and feed treatment may risk the product from being washed off of the leaves of the weed.

Conclusion on Mowing and Weed & Feed:

Weed and feed are great products to use, but there are some considerations to be taken.

Mowing is an important part of proper lawn care. It promotes a thick and healthy looking lawn as well as choking out unwanted weeds. There are, however, a few rules that need to be followed when treating your lawn with weed and feed.

As you can see from the above information, it is generally not recommended to mow right before and straight after applying weed and feed to your yard. Rather mow your lawn a few days before weed and feed application, if you want the most of the treatment.

As a rule of thumb, when it comes to mowing height, you should try to keep the grass blades on your lawn at a height of three to four inches when using weed killers. Refrain from mowing the grass shorter than 1/3 of its height.

Weed and feed is great to use to rid your lawn of pesky weeds as well as boosting the grasses’ health. It is, however, not as effective when wanting to get rid of grass-like weeds. Crabgrass products will be more effective on grass like weeds.