Should I Apply Weed Killer Before or After Mowing?

To ensure your lawn looks nice and well-kempt, you will need to perform weed elimination regularly. Applying weed killers or herbicides is a common method since they can eradicate unwanted plants and weed quickly. However, there are a lot of questions gardeners and lawn owners ask when it comes to using weed killers effectively.

One of the frequently asked questions is, ‘should I apply weed killer before or after mowing?’ You might be wondering whether you need to mow your lawn before application or wait for a few days after mowing to spray weed killer.

Read on to find out whether to apply weed killer before or after mowing!

should i apply weed killer before or after mowing

Should I Apply Weed Killer Before or After Mowing?

The short answer is: Apply weed killer BEFORE mowing your lawn, though this depends on what kind of weed killer you are using.

But why? Don’t you want to get as much weed away as possible for weed killers to work?

Weed killers come in spray or granule form. Chemicals would prohibit weed germination, reducing and killing weeds over time. The best time to apply weed killers, specifically preemergent herbicides, is early in the season before weed is expected to begin flowering.

The optimum months for weed killer application are between April to early June. Spray-on weed killers will have to sit on the surface for a certain period, which is why it’s best to apply them when the grass is expected to remain dry for a few days. With granules, they need to be absorbed into the ground, so these should be applied before watering or before storms.

With preemergent weed killers, you will want to mow your yard BEFORE application. If you mow your yard after application, the weed killer would spread chemicals over a broad area, damaging plants and shrubs. It may even attach to your cut grass, and if bagged or raked, it will be removed from the yard, reducing the chemicals on the lawn.

When mowing your lawn, cut your grass to about 2-3 inches tall, mowing frequently. Apply the week killer right away for effectiveness and either water your grass or leave it dry, depending on the type of weed killer you used. You can mow the lawn again a few days after the weed killer has settled.

When to NOT Mow the Lawn

When using post-emergent weed killers, you should avoid mowing your lawn until AFTER a few days of weed killer application.

This is because when mowing, you will eliminate most of the weeds’ upper growth. Since weed killers work well through contact, and the more leaf surface there will be to cover, the quicker it kills the weed. This kind of weed killer will require as much leaf blade as possible so the plants will absorb the chemical.

If you mow before or immediately after application, especially when bagging the clippings, you may break the chemical barrier or remove it altogether before it can destroy any weeds.

If you have just mowed your lawn, wait for about 3-5 days before applying weed killer. Then, your weed killer will need time for it to take effect.

Avoid mowing your yard for at least two days. Furthermore, keep away from the lawn for 24 hours after applying the weed killer, and do not water your lawn immediately after application, as this would wash away the chemicals before doing damage to the weeds. If ever it rains, then you’ll have to reapply the post-emergent weed killer.

Wrapping It Up

For a beautiful and weed-free lawn, you’ll need to have things shaggy, as weed killers are most effective with more leaf surface. That’s why it’s recommended to apply weed killer before mowing and to wait for a few days until mowing the lawn. If not, then wait a couple of days after mowing your lawn to apply weed killer for it to work well.

Hopefully, this article gave great insight on the best time to apply weed killer. Now that you know the answer, schedule your mowing and weed killer application to keep your garden looking clean and fresh!

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