Why Do Weeds Grow Back After Spraying Them?

Landscaper sprays weeds

There’s nothing more frustrating than spending time, money, and energy on something just for it to not work. When you spray your garden weeds and come back to find more weeds growing in its place, you might feel like you’re out of options. Luckily, you’re not alone.

Weeds grow back after you’ve sprayed them because they still have roots or seedlings in the soil. Although spraying will kill the weeds, it won’t stop the roots from producing more weeds or the seeds from sprouting. There are more effective methods for getting rid of weeds for good.

Weeds commonly grow back and it has little to do with whether or not you sprayed them correctly. Below, I’ll tell you why weeds are so resilient, how to get rid of them for good, and give you some tips for making your spray method work better.

Why Weeds Grow Back After Being Sprayed

The definition of a weed, according to Merriam-Webster, is “a plant that is not valued where it is grown and is usually of vigorous growth, especially one that tends to overgrow or choke out more desirable plants.” By this definition, technically, anything can be a weed if you don’t like it in your garden.

Weeds are essentially just the right plant in the wrong place. What makes weeds different from your normal flowers is their ability to overgrow and choke out your plants.

By this, I mean that they wouldn’t be weeds if they weren’t so hard to get rid of. By nature, weeds take a little more effort to kill than just picking or spraying them.

Sometimes coming to terms with the weed problem is about changing your outlook on what’s growing. Other times, the desire to get rid of the weeds is valid and necessary. Invasive species can be harmful to your garden’s ecosystem and are often encouraged to be weeded out by your local forestry and wildlife department.

Additionally, you don’t want your plants to get choked out. Weeds can absorb nutrients your plants desperately need to grow. Understandably, you may want to get rid of those weeds for good. To do this, you’ll need a little more than spray.

Weeds Need To Be Killed at the Root

When you spray down weeds, you’re only killing the part of them that lives above ground. Think about the Titanic and how it hit the iceberg–there was a ton of iceberg floating just beneath the surface that the ship didn’t notice.

There are many things about your weeds you may not have noticed.

  • The seeds could have already spread throughout your soil.
  • The roots below ground could still be doing well.
  • There may be a few baby weeds you missed when spraying.

That’s why you have to get down to the root to get rid of weeds.

Methods for Getting Rid of Weeds Determine Grow-Back Rate

Sometimes your weeds growing back have less to do with the weeds and more to do with how you tried to get rid of them in the first place. Hand pulling is the least effective because it only usually gets rid of the top layer of a living weed and helps the weed spread its seeds around.

Dandelions are a great example, especially when they go from yellow to white. When we blow the white puff on end, the seeds spread to other parts of our garden lawn. Other weeds find a way to spread even after we pull them. Certain weeds with invasive habits will find ways to grow and spread quickly.

A few methods work for killing weeds, but they work best in tandem with other methods. Most people will use:

  • Weed killing spray or herbicides
  • Mulching
  • Fertilizing Soil
  • Hand pulling

However, these don’t usually work on their own. If you have a resilient species of weeds living in your garden, it could take using all of them to get rid of the weed for good.

Weed Killing Sprays and Herbicides

As mentioned above, weed sprays won’t make all of the killings. They’ll do a good amount of work and make the process easier for you, so you don’t have to skip it altogether, but if you have other plants in your garden you’re afraid of harming, you can skip it.

Weed sprays will kill anything above the surface and make it easier for you to pull the plants out. It’s good to apply weed killer if you want to pull the weeds. Otherwise, you’ll spread the seeds out and leave the roots below even when you pull.


Mulching is a great way to suffocate weeds. If you are shutting down a shop in your garden or a section of your lawn that gets extra weedy, you can cover it with a layer of mulch to ensure the weeds underneath die out.

Mulching works great in tandem with the weed spray method. You can also use mulch if you hand pull and want to ensure the living roots or sprouting seedlings don’t grow to maturity.

Fertilizing Soil

You should weed what you can before fertilizing and try other methods of getting rid of weeds. Fertilizing gives your soil the proper nutrients to grow healthy grass, flowers, or edible crops.

Applying a layer of fertilizer won’t necessarily get rid of weeds, but it’ll make your desired plants strong enough to withstand the chokehold that the weeds have on them.

Hand Pulling

Pulling the weeds is fine if you have no other resources available, but proceed with caution. When we pull weeds up from the ground, we spread the seeds and leave the roots below to grow. When you pull, you’re only getting rid of the weeds you can see.

This does not change the fact that hundreds of little seeds are likely planted throughout your garden, doing what they do best to survive (being pollinated and spreading their seeds in the wind).

If you are going to hand pull, you have to use one or more of the above methods for the weeds to go away for good. Otherwise, they’ll likely pop up again once they’re through their next life cycle.

Gardener pulls weeds.

Some Weeds Need Specific Strategies

There are a few gardening hacks for getting rid of weeds that aren’t technically “by the book.” Some gardeners will pour boiling water over the plants for those weeds that grow in between sidewalk cracks or pavement. This is a better strategy for these weeds because it can be hard to get to their roots.

Mint is also a common invasive weed. Though many enjoy growing mint in their gardens, others have found that there are consequences of sowing them directly into the ground rather than keeping them in a container (as most growers suggest). The best way to get rid of a mint plant is to use salt, dish soap, and white vinegar.

Try to identify the weed you have grown and see if there are any old wives’ tales about how to get rid of them. If you’re at your wit’s end, they’re at least worth giving a shot!

How Can I Get Rid of Weeds for Good?

So, with all of that information, you may be wondering if there are any quick and easy ways to get rid of the weeds for good.

You can get rid of weeds for good by using various strategies at once. Spraying, pulling, fertilizing, mulching, and using herbicide should do the trick to get rid of those weeds forever. Otherwise, they may keep sprouting up.

Unfortunately, none of these methods are one-and-done or quick-acting. You have to invest some time and possibly money to get rid of your weeds. Otherwise, they’ll keep sprouting back up.

Do I Need To Pull Weeds After Spraying?

If you feel discouraged about the amount of time and energy you’re about to spend getting rid of your weeds, you may be looking for steps that you can skip. Pulling the weeds after spraying may seem unnecessary because they’re dead. However, keep this on your to-do list.

You need to pull weeds after spraying, but you should wait until they are fully dead before you pull them out. After the weeds die, you can begin pulling so that no other active roots or seeds will begin to grow. Otherwise, the spraying was pointless.

Dead weeds are much easier to pull than living ones, so they shouldn’t add too much labor or energy to your project.

Final Thoughts

Weeds are supposed to be hard to get rid of; that’s why they’re weeds! Invasive species are detrimental to your ecosystem, and pesky weeds take up precious space in your garden.

Unfortunately, pulling won’t be enough if you want to get rid of your weeds for good. You’ll need to enact a combination of spraying, mulching, and prevention methods. Sometimes, this takes multiple growing seasons.

Stay proactive by learning about the weeds in your area. Not all weeds are built the same, and you might be surprised to find the hacks other gardeners use to rid certain species.


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Plantician Guy (Mike)

Hi I'm Mike, a self-proclaimed plantician (an invented profession to describe a plant enthusiast). Based in Sydney Australia, I enjoy the great outdoors and the greenery things around the garden, in particular, indoor climbing plants.

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