How to Kill Weeds

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Weeds are one of the most prevalent issues homeowners deal with in the spring and summer months. Getting rid of these invasive plants requires proper equipment and techniques.

There are many different methods of removing them such as manually removing them by hand, cover mats, or herbicides. We review all of these and much more in our article below. We will cover all aspects of removing these unwanted plants to make sure that they do not return and cause an eyesore on your lawn.

An overview picture of how to kill weed. In the picture itself are 4 bright yellow dandelion flowers

Different Control Methods

There is no magic bullet when it comes to keeping weeds out of your lawn. However, there are different ways of mitigating their opportunities to thrive and grow. 

Combine the following methods as you see fit to formulate an effective strategy against these invasive plants.

A Weed Eater is a Bad Idea

What?  How can that be?  By its very name, you would presume that it should be at the top of the list for effective methods.

Well, it is at the top of the list.  But just not for the reasons you imagine it to be.

A weed eater is an important piece of lawn equipment that is crucial for proper lawn maintenance.  Your lawn mower cannot fit into tighter spaces or around in-ground irrigation systems and playground equipment.  You cannot just allow those areas to grow wildly.  In these cases, you can use it to cut your grass to its proper height.

You can even turn it on its side, so the string spins vertically to edge around flower beds and driveways.

weed whacker may be good for getting rid of grass where lawn mowers cannot reach

However, they are not effective methods to control weeds.  To remove these invasive plants from your yard, you must remove it in its entirety.  Just knocking off the part that you can see is not nearly enough.  Any tool or method that leave pieces of the roots behind only guarantee that you will have to return to that same spot to do it again.

In truth, a weed eater can do more harm than good.

The string rotates violently around, cutting down any growth that is standing in its way.  At the same time, the string’s rotation throws the clippings from its conquest around in a very random fashion.

So when you cut plants like dandelions, which carry up to 15,000 seeds per plant, you have actually helped them out a great deal.  You are inadvertently spreading thousands of seeds randomly throughout your yard.

Weed whackers or weed eaters can spread dandelion seeds and also destroy grass. Pictured here is someone using a wheed wacker hitting a bunch of dandelions

Prevention

Keeping your lawn up with proper maintenance techniques is the best preventative measure.  A healthy lawn does not give invasive plants a suitable environment to thrive.

Small things like mowing your yard as it should be mowed is one step towards preventative maintenance.  You should ensure you are keeping your grass at the proper height range for your grass type. 

Aeration and fertilization are also two key pieces of a healthy lawn defending itself.  These promote a complex, deep root system that makes it difficult for them to establish.

It is important to find out the specifics of what is needed for the grass in your lawn to prosper and flourish.  Proper maintenance is different for every lawn because every lawn is different from the next.

A lawn filled with dandelions

Hand Pulling

Nothing beats hard work and sweat.  This is the preferred method for nearly all invasive plants.  Doing this will ensure that the entire taproot or root system is removed.

It is an exercise in futility to pull them out by hand if you do not remove all of the plants’ roots.  Leaving pieces of the root system will guarantee that the invasive plants will be making a second appearance.

To make your life easier, it is best to manually de-weed your lawn when the soil is wet.  The moisture from rainfall or your irrigation system will loosen the soil around the roots making it easier to pull up without leaving pieces behind.

Someone grabbing out a weed and taking out its root system

Add Mulch

There are several benefits to adding mulch around your shrubs or vegetable garden. 

Mulch will prevent the weed seeds from gathering the sunlight that they need to germinate.

Mulch also retains moisture and provides nutrients to the soil as it decomposes over time. Placing it adjacent to your shrubs or around your garden will help keep the soil healthy—healthy soil results in healthy plants.

Dig Them Up

If weeds seem to grow in the same spot, time after time, you should probably go out to the shed and grab the shovel.  The problem is that when you pull it by hand, try as you might, you are still leaving some of the root system in the soil.

Using a spade, a digging fork, or a trowel, dig down several inches into the soil.  Remove it and inspect the area for remaining pieces of the root structure that you need to remove.

A man grabbing out weeds with gloves on

Reduce Open Garden Space

If the soil in and around your garden is rich and drains well, then it is a good idea to place your plants closer together.  Growing your plants closer together will prevent weeds from taking hold.  The shadow casted by surrounding plants makes it difficult for invasive species to receive essential sunlight.

By doing growing closer together, you also get the benefit of having a thicker root system.  This, again, makes it difficult for other invasive plants to establish themselves.

Use Drip Irrigation

This form of irrigation allows you to have fine control of where you are watering.  Regulating the amount of water you put in a particular area will make it more difficult for the invasive plants to obtain the nutrients it requires to grow.

Plants surrounding by a drip irrigation system

Weed Cover or Mat

Placing plastic sheeting over the ground below your garden or flower bed before you put down soil or mulch will inhibit the growth of weeds.  Sunlight that they need to grow will be unable to penetrate the surface.

These plastic sheets will also kill anything that attempt to grow by way of the greenhouse effect.  The greenhouse effect raises the surface temperature to uninhabitable levels.

You can also put down wet newspaper shreds.  The newspaper will eventually decompose, but it will still prevent sunlight from reaching the surface and prevent germination.

Herbicides

When all else fails, you can resort to using herbicides.  Different types are used for killing different varieties of weeds.

There are plenty of different types of commercial chemical herbicides sold at garden stores. If you have kids or pets that are out on your lawn frequently, you will want to look for natural killers that are safe to use around people and pets.

You can even make some DIY homemade solutions. Keep reading below to learn more about this.

Someone spraying preventative, pre-emergent herbicide to prevent weeds

Different Types of Herbicides

Herbicides come with different delivery systems for different purposes.  To make sure you are using the right type on your lawn, let’s dive into some of the different types.

Pre-Emergent

Pre-emergent herbicides are designed to prevent the germination of seeds by inhibiting them from receiving a key enzyme during the germination process.  They are applied to lawns in the spring and fall in support of this prevention.

These are often called crabgrass preventers because they are most frequently used to grassy invasive plant. 

Because pre-emergent herbicides work, timing your application is the most critical aspect you should consider when using pre-emergent herbicides.

They come in both liquid and granular forms. 

If the weed has already sprouted and is visible, it is too late to apply a pre-emergent herbicide. 

A man spraying a lawn with weed killers

Post-Emergent

Post-emergent herbicides are applied once the weeds that can be seen above ground and are actively growing.

Herbicides like this kill the plant once it has shown itself.  They can prevent future growth as well.

Post-emergent killers come in different physical formulas (spray-on liquid or granular). Post-emergent killers are most effective in areas where the invasive plants are beginning to get out of control.

A man with a yellow container spraying post-emergent weed killers on weeds.

Contact Herbicide

Contact herbicides begin to kill the targeted plant the moment they come into contact with it.  It does this by absorbing into the plants’ stomata.  Stomata are tiny openings in the leaves of the plants.

Contact herbicides should only be used during the growing season as they are only effective at controlling plants that are actively growing and going through photosynthesis. 

The best time to apply contact herbicides is early in the day.

Herbicides like this are a favorite of homeowners because they can treat the weed without negatively impacting the soil or surrounding plants.  These types are effective at controlling annual weeds with one application.  For perennial weeds, you may need two or possibly three applications before you see results.

Contact herbicides can get rid of weeds effectively.

Systemic Herbicide

The majority of herbicides fall under this particular category. 

Systemic herbicides kill by entering the plant through the foliage and working its way through the plants’ transport system to spread through the entire plant.  They work their way from the root to tip.

These herbicides will kill the weed entirely because it attacks every living area of the plant. 

Residual WeedKiller

Use careful consideration before employing this particular type of herbicide as they will poison the soil surrounding the plant.  This poison will render it useless for future growth.

Avoid using residual types of herbicides if you plan to plant vegetation in the area in the near future.  These can sit in the soil for months following application.

Generally speaking, residual herbicides are used on worn pathways, driveways, and patios.  That way, there is no real growth that you have to worry about.

Selective Herbicide

Selective herbicides work to kill a specific type of weed and leave the surrounding soil and vegetation unharmed.

Broadleaf and narrow leaf weeds have different vascular and transport systems.  Selective herbicides are engineered to only attack plants with specific vascular and transport systems. 

Non-Selective Herbicide

Herbicides of this variety show no mercy to any form of vegetation.  They work in the same way as a contact weed killer but they do not discriminate between different plant life forms.

It would be best if you used extra care to not spray on any unintended targets when using this broad-spectrum herbicide.

When using non-selective killers, you should cover any vegetation you would prefer to keep alive.  Do not spray in windy conditions.  To avoid incidental contamination, you should also avoid walking over an area once you have sprayed it for a day or so.

Certain weed killers are non-specific and kill weed and grass alike. A man is spraying a bunch of dead grass with weed killer

“Weed and Feed” Combination Products

The chemicals found in these products are selective and they also contain nutrients to feed surrounding vegetation.

“Weed and feed” products are favored by consumers because of their convenience.  However, the overpowered chemicals contained within them will weaken turf in the long run.

These products can be used in the very short term, but are not viable for periods of extended use.  The expense that comes with the short term effectiveness of these products is sacrificing the long-term growth and overall health of your lawn.

Yellow dandelions in a field of grass

Homemade Solutions

The only sure-fire way of being 100% environmentally safe is good, old-fashioned manual labor.  But there are some natural alternatives that aren’t as toxic as their commercial counterparts.

You can find effective herbicides right inside your kitchen.  Surprisingly, there are many household compounds and methods that are effective at killing weeds.

Everything from corn gluten meal to dish soap to boiling water can be used in and around your lawn or garden. 

Corn gluten meal is a natural byproduct of milling corn and is available as a fine powder, pellets, or granules.  Corn gluten meal acts as a pre-emergent herbicide on your lawn.  The corn gluten meal will not harm established plants and plants with strong root systems.

By combining 1 gallon of white vinegar, 1 cup of rock salt, and 1 tablespoon of dish soap, you can create a natural cocktail that acts as a very effective weed killer. The acetic acid in the salt and the vinegar effectively draws vital moisture out of plants.

The dish soap, a surfactant, reduces the surface tension of the weed and will allow the mixture to be absorbed into the plant. 

Boiling water is also a quick and effective method.  Generally, boiling water is used for weeds on the driveway because you can target a single weed without damaging surrounding vegetation.

Boiling water works by breaking down a plant’s cell structure to kill it.

Considerations Effective Application

You need to consider a few factors before you grab your sprayer and head out to your lawn.

A beautiful green lawn

Weather

You should check the weather report and make sure that rain and wind are not in the forecast before applying herbicides.

Rainwater can wash the herbicide off the leaves of the weeds or dilute it to the point of being ineffective. 

Wind is something you will have to take into consideration before applying any herbicide, but particularly if you have chosen a non-selective variety.

Wind can create drafts that cause your herbicide to cover more area than you had intended.  This will result in damaging plants that you had meant to keep alive.

Mowing Schedule

If you have just cut the grass in your yard, you need to wait a few days so that the weeds’ foliage can grow back.

When you are spraying your herbicide, you want to cover as much surface area on the weeds as possible.  If you have just mowed correctly, then you will have decreased that surface area by ⅓.

A freshly mowed lawn with flowers in the background

Active Growth

You will only kill weeds if they are actively growing. 

Depending on your climate, you can start with a pre-emergent herbicide as early as April and continue with a post-emergent herbicide if weeds begin to pop up through October.

Before the lawn goes dormant for the winter, it is beneficial to apply a pre-emergent herbicide to your lawn just in case spring comes earlier than usual.  That way, the seeds don’t have the opportunity to germinate.

How To Apply

You should follow these steps for safe and effective application

  1. Read the label carefully to ensure you have the right product for the job
  2. Put on personal protective equipment (PPE) the label recommends for use
  3. Make sure you have the correct equipment and that it is working properly.
  4. Apply herbicides in continuous manner with very little overlap
  5. Clean the equipment after use by rinsing with water and flushing the nozzles
  6. Store the remainder of the product in a cool, dry place out of reach of children and pets
  7. Remove your clothes and PPE before going inside to wash your body.
  8. Take a shower (not a bath) and wash thoroughly with soap.

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About the author: Jeffrey Douglas is a horticultural hobbyist that loves everything related to plants and gardening. He specializes in gardens and houseplants.

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