How to Kill Weeds

|

Weeds. No one enjoys having to get rid of weeds. It’s an all too common situation – you have done everything you can think of to ensure the viability and health of your yard.  Then suddenly, weeds start popping up all over the place. What can you do about it?

This is one of the most prevalent issues homeowners and garden enthusiasts deal with every day.  Nothing sours the appearance of your lawn like these invasive, opportunistic plants.  These weeds will continue to grow and spread until they have taken over and compromised the health of your lawn.  Not to mention that it makes you feel all of your trouble and toil was in vain.

Before you throw up your hands in exasperated defeat, you should know that there are several ways to remedy this problem.  While nothing in lawn care is ever 100% effective (especially weed control), there are some things you can do to kill these weeds off before their invasion is a success.

A weed full of broad leaf weeds.

Not sure how to kill weeds that are taking over your yard?  Read on for details, tips, and instructions that will teach you everything you need to know about how to kill weeds that have become the uninvited guests crashing your lawn’s garden party.

What Are Some Different Weed 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 of treating weeds.

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 your weed eater 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

What you should not do is consider it an effective method for weed control.  To kill weeds in your yard, you must kill or remove the weed in its entirety.  Just knocking off the part that you can see is not nearly enough.  When dealing with weeds, killers 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, when it comes to controlling weed plants, a weed eater can do more harm than good.

The string from the weed eater 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.

The broadleaf dandelion weed can carry up to 15,000 seeds per plant.  So when you “kill” weeds like the dandelion with a weed eater you have actually helped them out a great deal.  They will gladly sacrifice one little plant in exchange for 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

So steer clear of cranking the weed eater up for this purpose.  The equipment’s name is a bit misleading as to its actual function.  Perhaps “weed seeder” is a more appropriate nickname.

Prevention

Keeping your lawn up with proper maintenance techniques provides it with the best defense against weeds in grass or vegetable garden.  A healthy lawn does not give the weeds 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 weeds to establish themselves.

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.  Killing weeds using this method is ideal for broadleaf weeds like Canada thistle.  This is the preferred method because you can ensure that the taproot or root system of the weed is removed in its entirety.

It is an exercise in futility to pull weeds by hand if you do not remove the weed and all of its roots.  Leaving pieces of the root system in the soil will guarantee that those invasive plants will be making a second appearance in your lawn. 

The easiest way of making sure you pull out every piece of these plants is to weed your lawn when the soil is wet.  The moisture from rainfall or your irrigation system will loosen the soil around the roots of the weed.  This will make them easier to pull up without leaving pieces behind.

Someone grabbing out a weed and taking out its root system

Mulch Over The Weeds

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. It will also keep plants growing from underneath it.

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 The Weeds 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 and loosen the weed.  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 plants closer together will prevent weeds from taking hold.  The shade provided by the plants makes it difficult for weeds to receive essential sunlight.

By growing plants closer together, you also get the benefit of having a thicker root system.  This makes it difficult for the weed to establish itself.

Use Drip Irrigation

This form of irrigation allows you to control which individual plant or specific area receives water.  Regulating the amount of water you put in a particular area will make it more difficult for the weed to obtain the nutrients it requires to grow.

Plants surrounding by a drip irrigation system

Weed Cover or Weed 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 the weed needs to grow is unable to penetrate the surface.

This will also kill the weeds 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 as a weed mat.  The newspaper will decompose and still prevent sunlight from reaching the weed seeds and prevent germination.

Weed Killers

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 weed killers sold at garden stores that kill weeds. If you have kids or pets that are out on your lawn frequently, you will want to look for natural weed killers that are safe to use around people and pets.

You can even make some DIY homemade weed killers. Please keep reading below to learn more about this.

Someone spraying preventative, pre-emergent herbicide to prevent weeds

Different Types of Weed Killer

Weed killers come with different delivery systems for different purposes to kill weeds.  To avoid the potential for using the wrong type on your lawn here is a breakdown of the different types of weed killer.

Pre-Emergent Weed Killer

Pre-emergent herbicides are designed to prevent the germination of the weed 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 an effective way of treating this grassy weed. 

Because pre-emergent herbicides work, timing your application is the most critical aspect you should consider when treating weeds with this herbicide.

This form of herbicide comes in both liquid and granular form.  Which one you choose is dependent upon factors like timing and weed type.

If the weed has already sprouted and is visible, it is too late to apply a pre-emergent herbicide.  At this point, it will not prevent the new weeds from growing.

A man spraying a lawn with weed killers

Post-Emergent Weed Killer

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

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

Contact Weed Killer

Contact herbicides begin to kill the targeted weed the moment they come into contact with it.  It does this by absorbing into the weeds’ 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 weeds that are actively growing and going through photosynthesis.  This timing will ensure the stomata is open to absorb the chemicals.

The best time to apply contact herbicides is early in the day because the stomata are open throughout the afternoon as the weeds go through photosynthesis.

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 Weed Killer

The majority of herbicides fall under this particular category. 

Systemic herbicides kill the weeds by entering the plant through the foliage and working its way through the plants’ transport system to spread through the entire weed.  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 Weed Killer

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 Weed Killer

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

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

Non-Selective Weed Killer

Herbicides of this variety show no mercy to any form of vegetation.  They work in the same way as a contact weed killer but 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 weed 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

This product will kill two birds with one stone.  When you feel that you need to feed your lawn while at the same time dealing with the weeds, killer chemicals are combined with nutrient-rich fertilizer to give you “weed and feed” products.

The herbicide found in this combination is selective to minimize any harm to the other vegetation surrounding the intended target plants.

“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 of the short term effectiveness of “weed and feed” combinations is sacrificing the long-term growth and overall health of your lawn.

Yellow dandelions in a field of grass

Homemade Weed Killer

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 around your lawn.

Everything from corn gluten meal to dish soap to boiling water can be used to kill weeds 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 weeds.

The dish soap, a surfactant, reduces the surface tension on the weed and will keep the mixture from beading up on the leaves and not absorbing. 

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

Boiling water is effective because it is said to break down the weed’s cell structure and kill it.

Considerations For Safe and Effective Weed Killer Application

You need to consider a few factors before you grab your sprayer and head out to the lawn with some potent weed killer.

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. 

The wind is an essential factor to consider for every type of herbicide, but especially if you have chosen a non-selective variety.

Wind will ultimately create an incidental drift as it gusts around you and will result in your weed killer covering a whole lot more area than you ever intended.  In turn, this will kill plants that you probably wanted to keep alive.

If You Just Mowed Your Lawn

If you have just cut the grass in your yard, you need to wait a few days for the grass and accompanying weeds to return. 

You want to cover as much surface area of the weeds as possible when you spray herbicides.  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

When To Apply Weed Killer

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 Weed Killer

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.

The Green Pinky

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

Subscribe
Notify of
guest
0 Comments
Inline Feedbacks
View all comments