Does Fertilizer Kill Weeds? [3 Ways Fertilizer Stops Weeds]

Standard fertilizer does not kill weeds. It provides nutrients to the soil that can be taken up by any plant growing in your yard, including weeds. However, if you kill weeds before you fertilize your lawn, your grass will grow thicker and healthier, discouraging new weeds from invading. Additionally, by adding nitrogen to the soil via fertilizer, you make soil conditions less inviting to many types of weeds. If you want to kill weeds and fertilize your lawn at the same time, you can use a Weed and Feed fertilizer.

Does fertilizer kill weeds?

Kill Weeds Before You Fertilize

In the simplest sense, fertilizer is plant food. Although your fertilizer may be designed with grass in mind, if you have a lawn full of weeds, they will benefit from fertilizer as well. For this reason, it’s a good idea to use a weed control product before you fertilize. Once you’ve killed the weeds, any fertilizer you spread will be used by your grass only.

  • Fertilizers can fuel the growth of both weeds and grass.
  • Live weeds may steal fertilizer from the ground, preventing grass from getting its fair share.
  • Apply a weed killer product to your lawn to kill weeds before you spread fertilizer.
  • Once your lawn is weed-free, only your grass will benefit from fertilizer.

Make sure to use the right weed killer to control the types of weeds on your lawn. A broadleaf weed killer will work to control non-grassy weeds, but crabgrass, sedge, and other grassy weeds require specialized weed control products.

3 Ways Fertilizer Helps Control Weeds in Your Lawn

Once you have killed the weeds in your lawn, it’s time to keep them out with fertilizer. Although fertilizer won’t wipe out weeds on its own, it can prevent weeds from returning. With the right fertilizer program, you can grow a healthy lawn that remains weed-free on its own. This way, you won’t have to battle the same weeds year after year.

Makes Soil Less Friendly to Weeds

Several common weeds, including dandelion and clover, thrive in soils with low nitrogen content. Coincidentally, grass struggles in soil with low nitrogen levels. Because most lawn fertilizers contain nitrogen to promote grass blade growth, fertilizer performs the dual function of helping your grass grow thicker at the same time it makes the soil less friendly to many species of weeds.

  • Weeds such as clover and dandelion flourish in soils with low nitrogen content.
  • Grass struggles in nitrogen-deprived soil.
  • Apply a nitrogen fertilizer to boost grass growth and make soil conditions less hospitable to weeds.

When applying nitrogen fertilizer, be cautious—too much nitrogen too fast can damage your lawn. Consult product label rates to find the correct amount of fertilizer to be spread per square foot of lawn. Additionally, it’s beneficial to follow a hybrid lawn fertilizer schedule that includes gentle fertilizers.

Encourages Thick Grass Growth

Lawn fertilizers are engineered with the nutrients essential for grass root and blade growth. By applying fertilizer to your entire lawn, you encourage grass to grow thicker and faster. Fertilized grass will also reclaim bare patches in your lawn. A thick, healthy, well-fertilized lawn forms a carpet. Any weed seeds that try to sprout in thick grass will struggle to take root and are likely to die.

  • A well-fertilized lawn reclaims bare areas where weeds typically take root.
  • A thick lawn resists weed rooting and smothers weed seedlings as they attempt to sprout.
  • By fertilizing, you are replenishing the soil with natural nutrients.

Fertilizer isn’t made of dangerous chemicals. The nutrients in fertilizer naturally occur in soil. However, if your lawn is left unfertilized, nutrients will be gradually pulled from the soil by plants and water runoff. Fertilizing is your way of giving back to the soil and ensuring good grass growth moving forward.

Promotes Faster Spring Green Up

A well-fertilized lawn is able to store energy in its roots to survive winter dormancy. This healthy grass then emerges from winter dormancy with plenty of stored nutrients. It bursts into life in spring faster, before weeds have a chance to take root.

  • Grass stores energy from fertilizer to survive winter dormancy.
  • After winter dormancy, this stored energy helps grass turn green faster in spring.
  • The faster your lawn greens up, the less chance for weeds to take root and invade your lawn.

If your lawn is plagued with spring dandelions and crabgrass that appear while your turf grass is still brown, it’s likely because your lawn lacks fertilizer. If your lawn turns green quickly in spring, it can help smother weeds and eliminate notorious spring annual weeds.

Is Weed and Feed Good for Weed Control?

Weed and Feed products combine fertilizer with a broadleaf weed killer and/or a pre-emergent that stops weed seeds from sprouting. This type of fertilizer product can be extremely effective because they allow you to kill weeds and feed your grass at the same time. If you want a single-product solution, use Weed and Feed.

  • Weed and feed with a broadleaf weed killer will wipe out weeds and boost your lawn at the same time.
  • Use a weed feed and with crabgrass preventer in spring when you would otherwise apply a pre-emergent.
  • Use this Weed and Feed product in spring to feed your lawn, kill existing weeds, and prevent new weeds from sprouting.
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02/29/2024 08:06 am GMT

Keep in mind that any Weed and Feed that contains a pre-emergent will also kill grass seeds as they sprout. If you have seeded grass in the past 2 months, use this Weed and Feed that won’t harm your seedlings.

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Will Fertilizer Help Weeds Grow?

Fertilizers will feed both weeds and grass that are actively growing in your lawn. This is because fertilizers contain nutrients that are essential to plant life. For this reason, only apply fertilizer to your lawn after you have killed any existing weeds. If you apply fertilizer without killing weeds first, the weeds may rob most of the nutrients from the soil before your grass can absorb them.

  • Most weeds will experience a growth boost if provided with fertilizer.
  • Kill weeds before you apply fertilizer, to make sure you feed desirable grass only.
  • Weed and Feed products combine fertilizer with weed killer, so you don’t have to worry about weeds benefitting from a fertilizer application.

Because Weed and Feed products contain systemic broadleaf weed killers, they attack weeds down to the root at the same time the fertilizer in the Weed and Feed enters the soil. This ensures that the fertilizer is only taken up by the grass, while the annoying weeds wilt and die.

How Can You Thicken Your Lawn to Kill Weeds?

Thickening your lawn won’t kill weeds on its own, but a thick lawn is very resistant to new weed growth. Make sure you kill all the existing weeds, then embark on a lawn maintenance program to stop weeds from coming back. The most important elements of a lawn care program that promotes thick grass are:

  • Use weed killer when necessary to eliminate existing weeds.
  • Water your lawn deeply twice per week.
  • Practice proper mowing practices for your grass species during the growing season.
  • Fertilize your lawn on a schedule designed to feed the grass from spring green-up until dormancy.
  • Aerate and dethatch your lawn annually.

By providing grass with adequate water, mowing it to the proper height, and feeding it with fertilizer throughout the growing season, you will cultivate a thick, green lawn that chokes out any weeds that try to sprout. It’s also a good idea to remove excess thatch, aerate compacted soil, and even monitor your soil pH to ensure your lawn is a safe haven for grass.

Will Fertilizing Your Lawn Kill Weeds?

An application of fertilizer will not kill weeds in your lawn. In fact, any established weeds will benefit from the fertilizer, growing even more vigorously. Fertilizer can be very beneficial to lawn weed control though. The key is to kill the weeds first, then apply fertilizer. A well-fertilized, weed-free lawn grows thick grass that stops new weeds from sprouting. You can even kill weeds and fertilize at the same time with a Weed and Feed product.

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