How to Kill Weeds in Grass and Keep Them From Coming Back
The secret to killing weeds could be in your cabinet
Trying to kill weeds can feel like a long game of whack-a-mole: Whenever you knock one down, another one seems to pop right up. This little dance can make store-bought herbicides seem very appealing. With the right approach, however, you can control and kill weeds in your yard without using any harsh chemicals. You may even be able to rid your yard of weeds with something you have in your cabinet right now; read on to learn how.
How to Identify Weeds in Your Yard
No matter what weed type is common for your area, you’ll want to try and prevent them from growing and spreading seeds by addressing the weeds before they germinate (go from a seed to a plant, typically after a period of being dormant).
The type of weed you have determines when you should begin the removal process and which weed-killing method works best. The simplest way to classify weeds is by using their average life cycles.
Annual Weeds
These plants complete a full life cycle in a year or less. That means they germinate, grow to adulthood, flower, produce seeds, and die all before the year is up.
Some annual weeds, like crabgrass, germinate in the spring, so start your prevention right when the desired flowers in your yard begin to sprout from the ground. Other annual weeds, like henbit and annual bluegrass, grow in the fall, so concentrate your efforts at the onset of the season well before the leaves start to fall off the trees.
Biennial Weeds
These weeds have a two-year life cycle, so they survive two full growing seasons before dying. During the first year, they germinate and focus on growth. During the second year, they flower, produce seeds, and die.
You want to eliminate these troublesome seeds before they grow and produce seeds of their own, so start addressing them at the beginning of their initial germination process. Just like annual weeds, this time frame varies depending on the actual plant.
Perennial Weeds
The heartiest weeds hanging around your lawn are perennial plants, as they live much longer than just two years. Just like annuals, however, there are both cool-season perennial weeds and warm-season weeds. Try to remove them during their initial germination.
How to Control and Kill Weeds
It’s important to remove weeds for aesthetic reasons but also for the health of your entire outdoor ecosystem. Weeds, after all, compete for essential resources with desired plants and grasses. Additionally, some weeds produce allergens, which can wreak havoc on you and your family during peak pollen and allergy season.
Here are tried-and-true methods to control and kill harmful weeds in your garden and yard, several of which you can follow using items you already have in your home.
Landscape Fabric
If you’re just planning the layout of your exterior space but want to ensure that weeds don’t crop up alongside your new, beautiful plants, use landscape fabric. Buy a high-quality fabric and avoid plastic products since plastic won’t allow moisture to reach the plants that need it.
Lay the landscape fabric on top of the soil, which will prevent weeds from germinating but still allow nutrients to get to desired plants. Landscape fabric can also help get rid of weeds in rock beds, which is a nice bonus.
Pull up any weeds before laying down the fabric.
Secure the sheet with landscape fabric staples. Use one staple for every 10 feet of fabric.
Plant any flowers or grasses you want in your yard. For flowers that have already bloomed, carefully cut out the fabric around the base of the plant.
Place mulch over the entire sheet of fabric.
Yank Them by the Root
A tried-and-true method of tackling a pre-existing weed problem is simply pulling weeds up by the roots, which is as budget friendly as it gets.
Make sure the ground is moist. If it’s too dry, pour a small amount of water around the weeds and let it soak into the soil for a few minutes. If it’s too saturated, wait until the area dries out to remove the weeds.
Make sure the soil isn’t too firm. Use a rake to loosen any compacted soil around the plant.
Firmly grab the base of the weed and gently pull until you’ve removed the entire plant. If the process sounds too difficult or getting the weed up is presenting a challenge, grab garden claws or a trowel to make the task easier.
Keep in mind that this does not work for all weed types. For instance, if you need to get rid of quack grass, use a weed killer instead.
Use Mulch
Mulch keeps soil and plant roots cool, prevents frost accumulation in winter, and helps beautifully tie together your entire garden bed or landscape. Placing mulch around your plants also helps them conserve moisture while preventing light from getting to weeds, thus discouraging unwanted growth.
Buy shredded or chipped bark from your local home improvement store.
Apply a 2- to 3-inch layer of mulch around your plants to prevent sunlight from getting through to the weeds, leaving a small gap at the base of the plants. (If you put the mulch too close, it can cause the plant to retain too much moisture and rot.)
Apply Corn Gluten Meal
Corn gluten meal prevents many types of undesired plants from growing, like crabgrass, dandelions, chickweed seeds, and more. It’s a pre-emergent herbicide, meaning that it only works before the plant has already sprouted. If you already see fully-formed weeds, it’s too late to use corn gluten meal.
Generously scatter the corn gluten meal over the soil, using roughly 10 pounds per 500 square feet.
Lightly water your yard so the corn gluten meal sticks to the weed seeds.
Repeat the process in both early spring and summer to handle different types of weeds.
Burn Them Away
Fire is great for cooking and staying warm but not so great for sustaining plant life. If you want to use this sure-fire weed-killing solution, first get all of your safety materials together. Put on fire-resistant gloves, heavy-duty work boots and pants, safety goggles, and a mask before even turning your torch on.
Wait to start until you have a non-windy day just a few days after a recent rain.
Remove all flammable materials from the area, including leaves and twigs.
Water the entire area around the weeds.
Using a handheld propane torch positioned 2-3 inches above the weeds, burn all the unwanted plants you see.
If you don’t have access to a torch, boiled water will also do the trick. Just pour the hot water directly over the weeds in your yard. You will see the foliage begin to wither almost instantly, but you’ll need to reapply boiling water two or three more times (with seven to 10 days in between) to make sure the weed is gone for good.
Burning the weeds, whether with fire or boiling water, is best for spot-treating gaps between bricks or concrete where young weeds creep up. They will both easily kill any plants they come into contact with, so be careful where you use them.
Use Vinegar
Vinegar isn’t just for salads; it also makes for a handy weed killer. White vinegar that you buy at the store will work in a pinch, but it’s not quite as potent as horticultural vinegar. You can up the weed-killing power of store-bought vinegar, however. Just can add one cup of salt and one tablespoon of dish soap to one gallon of vinegar.
Always use protective equipment and double-check your measurements when mixing any chemicals. When in doubt, reach out to a lawn care specialist near you to handle any chemical-related needs.
No matter what type of vinegar you use, however, the process remains the same.
Wait to start until you have a non-windy, non-rainy day to prevent the vinegar from blowing onto plants you want to keep or being diluted by rainwater.
Put on gloves and a mask to protect your skin and face from irritation.
Use a spray bottle and apply vinegar directly to all parts of the weeds, making sure to fully saturate the foliage.
Plant Ground Covers
Weeds look for open, bare soil where they don’t have to compete with other plants for nutrients. Ground cover plants are low-growing plants that widely spread across the soil, making it difficult for weeds to sneak into your yard.
Creeping thyme, ajuga, aronia, and mondo grass are just a few varieties of ground cover that do a great job of preventing weed growth.
Consider an Herbicide-Free Approach
Herbicides and pesticides can cause side effects in gardens and lawns. Still, many people use them because they’re fast-acting and quite effective.
However, pesticides and herbicides can create health problems for you, your family, and your pets. According to the National Pesticide Information Center, glyphosate, one of the most common active ingredients in a majority of brand-name herbicides, can cause eye, nose, throat, and skin irritation.
If you accidentally ingest the herbicide (typically by breathing it in directly), you could experience nausea, vomiting, and GI symptoms. Pets are particularly at risk, as they tend to eat plants when let outside, which could cause them to experience similar symptoms as humans.
Not only can herbicides cause problems for you and your loved ones, but they can also harm wildlife that’s critical to your garden’s ecosystem, like butterflies, bees, and more.
Consider using herbicide-free solutions or making homemade weed killers to tackle your weed problem and maintain a happy environment for you and your yard’s flora and fauna.
Why Weeds Can Be a Good Thing
You might not kill and control every weed in your yard, but don’t fret. Weeds have some beneficial properties that you may not know.
These resilient plants often attract beautiful butterflies and caterpillars and can be their main food source. Dandelion and clover, in particular, are delectable to the buckeye butterfly and eastern tailed blue butterfly. In addition, weeds attract several beneficial insects (like ladybugs and praying mantises) that eat harmful insects (like aphids).
Weeds can also keep your topsoil in better shape during drought conditions when other plants, like grass, die off and wait for wetter weather.
So control the weeds you can, but don’t sweat the ones you can’t. Even if your yard has more weeds than you might like, it might actually be healthier for it.
DIY vs. Hiring a Professional
There are many reasons to go with a local weed control expert instead of trying to remove unwanted plants yourself. First of all, there’s the matter of scale. Removing a few weeds here and there by yourself is easy, and most people have no problems tackling this project on their own.
If unwanted plants cover your lawn, however, the amount of time and labor required to get rid of them quickly increases. In these cases, you may want to call in a professional. A weed control specialist typically costs an average of $100 per treatment.
Even if you know the basics of how to kill weeds in grass, the process is still deceptively complex due to germination schedules, fertilization schedules, and the risk of accidentally damaging your preferred plants. For instance, the wrong type of herbicide could target your favorite plants over weeds, and applying a solution at the wrong time does nothing at all. If something goes wrong, any money you saved by DIYing will come out of your pocket later to fix the issue.
C.E. Larusso contributed to this piece.
Frequently Asked Questions
Very carefully. You should be cautious when using any of the above methods, as any one of them could lead to you accidentally killing desired grasses and plants. However, there are selective herbicides that can target certain plants over others. Look for a product that only affects the type of weeds you want to eliminate and spares the plants you want to keep.
The quickest way to kill weeds is to burn them, pour boiling water on them, or pull them out by hand. Each of these methods works instantaneously. Beyond that, using vinegar or a vinegar-based solution works in a couple of hours, as do herbicides you can buy at the store. The slowest way to kill weeds is to starve them of nutrients and sunlight with mulch or fabric covers.
What you're really asking is what kills weeds down to the roots so that they can’t re-germinate. Flame does the trick, as does boiling water. Vinegar also works but requires multiple applications and two or three days to see results. Just because you kill off the weed and its root does not prevent future seeds from blowing in on the wind, however.
Vinegar cannot tell the difference between weeds and desired grass types; it kills everything it touches. Only use a vinegar or vinegar-based solution if you are relatively confident that you can navigate around the plants and grasses you want to keep. Also, don’t spray vinegar on a windy day, or it will blow onto other plants.