Even if all you have as far as outdoor spaces is a walkway, you likely have weeds to deal with.
Weeds are incredibly resilient, resourceful, and adaptive. (In many realms of life, these are great traits, and perhaps we all could benefit from emulating weeds, but that’s a topic for another day.) Defining what weeds are is divisive. Bring it up amongst interested parties and you’re likely to hear that weeds are just misunderstood plants, that all plants have a purpose, that they just need to be channeled to the right place. Because I don’t want to wade, well, into the weeds on this one, I will proffer that a weed is a plant you don’t want.
I’ve lived on the same 2 ½ acres in rural San Diego county for over 20 years. From the get-go, we committed to avoiding conventional herbicides (which means “plant-killer” in Greek) on our property. Even if it required a little more effort and creative thinking, we didn’t want ourselves, our children, our pets, our soil, or our air exposed to the unintended consequences of those easy fixes.
My approach to housecleaning and yard caretaking is pretty big picture. I prefer to think beyond the moment. The promise of advertising is that with one little spray, all your problems—be they grime or odor or weeds–will poof away. And maybe for the time being, they will.
But nothing is ever that simple. What if, in our efforts to make our living spaces – both indoors and out – clean, healthy, and attractive, we were making ourselves sick? Maybe not sick right away, but eventually? A bit of a cough becomes a chronic breathing issues, a tickle in the nose becomes an allergy to scents, an itch on our skin becomes constant redness and irritation. Is cleaning our houses and beautifying our yards worth the cost of our health?
Ok, I confess: I led you into a logical trap. These are not the only two options. You can clean and beautify your spaces inside and out without sacrificing your health or the health of others. But you’ll have to ignore a whole lot of advertising.
Table of contents:
- Why ditch chemical weed killers?
- Non-toxic weed killer methods that actually work
- Stopping weeds before they start: The best strategy is prevention
- The most targeted weed control of all: physical removal
- Other natural weed control methods
- Unexpected natural weed control methods
- Natural weed killer FAQs
Why ditch chemical weed killers? The case against glyphosate & 2,4-D
From the get-go, we knew that if we weren’t going to use conventional herbicides on our land, we were going to need really enduring reasons to carry us past the allure of a quick spray fix. Such products are so very common, easy to use, and really do deliver on what they promise: They clear weeds very quickly, saving lots of time and effort. And one thing we were short on—with a toddler, a newborn, a new job, and a new master’s program—was time and effort.
What is Glyphosate and 2,4-D and why are people concerned?
Glyphosate and 2,4-D are the active ingredients that have dominated the herbicide market in America. Glyphosate under the brand name “Roundup” is by far the front-runner. Though the World Health Organization (WHO) classifies glyphosate as a probable human carcinogen and 2,4-D as a possible human carcinogen, the U.S. Environmental Protection Agency, which regulates herbicides, says they are fine when used as directed on the label.
And there’s the hitch.
We need to look at the reality of exposure pathways and not just hide behind the phrase “use as directed.” Products applied to plants don’t just expose the plant, even when applied as directed and when the person doing the application is wearing the required protective equipment.
There’s going to be drift (compounds carried elsewhere on air currents), there’s going to be transfer (whose kid or dog doesn’t roll around on the lawn?), and then there’s the possibility of accident or misuse (the “oops” of a dog or toddler getting into the wrong cabinet or a sprayer misfiring). Why have that risk around?
And then came the lawsuits. In 2018, Dewayne “Lee” Johnson won his case against Monsanto Co. (the maker of Roundup, now owned by Bayer) that they failed to warn users adequately of the cancer risks of glyphosate. Johnson died in 2020, age 56, from non-Hodgkin Lymphoma. To date, Bayer has settled over 100,000 cases for approximately $11 billion, with tens of thousands of claims still pending, though has not admitted to a link between glyphosate and cancer.
While the glyphosate discussion dominates the press, there are other common conventional herbicides that carry their own hazards. 2,4-D is found in hundreds of products and is under scrutiny related to endocrine disruption, reproductive issues, and certain cancers. Another player is dicamba, extensively used on soybean and cotton fields, and it commonly drifts far and wide to other fields and environments.
The best method for controlling weeds depends on what the weeds are, where the weeds are, and how big they are.
The best safe alternatives to Roundup for home gardeners
Shunning these herbicides does not mean resigning oneself to weeds. There are quite a number of alternatives that work well without the side-effects, but there is not a one-size-fits-all solution to weeds. The best method for controlling weeds depends on what the weeds are, where the weeds are, and how big they are.
Non-toxic weed killer methods that actually work
Why I use boiling water to kill weeds in my patio
I’m not going to beat around the weeds here: boiling water is my personal go-to method for dealing with weeds in my paved patio. This was a too-easy-to-believe recommendation a friend told me about, but one round with my tea kettle, and I was sold.
This recommendation is exclusively for weeds that come up through hardscaping, like driveways, walkways, patios, and other hard surfaces. It works best when weeds are under 8″ tall.
Here’s the method:
- Boil water in your kettle. You can also use surplus boiling water from cooking, but putting it in a pitcher of some sort is helpful.
- Take care not to burn yourself.
- Douse the weeds with the boiling water.
That’s it. The next day, the weeds will be quite wilted. The following day they will have dried pretty thoroughly. In my experience, this desiccates the weeds completely and they do not grow back, though of course, in the great cycle of nature, there will be a new crop nearby all too soon.
Hardscaping is the only place I recommend this technique for a variety of reasons. First off, boiling water will kill any plant so it’s not great for lawns or gardens where there are many plants you want to keep. Second, it will also harm soil life such as garden-friendly earthworms, so you don’t want to pour this on soil. Third, running around a field of waist high weeds with boiling water is logistically impractical. I mean seriously, imagine what that would look like.
But if you have a patio or a walkway with some weeds coming up through the cracks, this is a great technique. If you have an argument for why this doesn’t work, tell that to my patio.
Why I don’t recommend other natural weed killer recipes
Folks, I’ve read about and tried many, many other natural weed control methods. For a variety of reasons, from efficacy to chemistry, I’m not a fan. My bluntness might be controversial, but I don’t want to mislead you on my opinion. Let me explain my issues with them one by one.
Is vinegar good for killing weeds? What you need to know
Vinegar is an acid. When you use it in your house, you have to take care not to use it on certain surfaces such as stone or metal because it will dissolve or corrode them. The same is true outside. If you regularly apply vinegar to your stone patio, you will eventually see it wearing areas away.
As far as efficacy, kitchen strength vinegar (usually around 4-5% acidity) takes a few applications to impact the weeds. If you opt for the more intense cleaning vinegar or horticultural vinegar, where the acidity can soar as high as 49%, this will undoubtedly kill the weeds, but you need as much personal protective equipment as you would with glyphosate, and any splash on stone or cement will most definitely etch it. As with boiling water, high acidity vinegar will kill any plant, so this is never to be used in an area with desirable plants or soil life. It can also impact the pH of soil.
Does baking soda kill weeds?
Applied directly to weed leaves, baking soda may impact some by drying them out. However, the minerals in baking soda, which are salts, can change the soil chemistry and impact the growth of desirable plants that you may want to add to the same spot.
How about hydrogen peroxide as a weed killer?
Once again, hydrogen peroxide is a substance that will kill weeds, or any plant. It would only be useful in an area that had no plants you wanted to keep. However, hydrogen peroxide is also a bleaching agent and can dissolve minerals in stone and cement. Used repeatedly, it could cause noticeable etching in your hard surfaces.
The “Three-Ingredient” natural weed killer (vinegar, salt & dish soap)
This is a weed-killing recipe I’ve seen a lot online, but I wonder if anyone has actually tried it. I did, and not only did it not work well, but if the salt were to run off into planted beds, it would seriously impact the chemistry of the soil and make it difficult to grow anything in it down the road. (Anyone remember the legend of Carthage, and how Rome supposedly sowed salt in their fields so they couldn’t rebuild?) If used on hard surfaces, the salt will leave residues that is unsightly as well. I’ve already addressed vinegar, and I tried the dish soap. It didn’t kill even my young, tender weeds.
Castile soap & vinegar – non-toxic weed killer?
One of my maxims is, “Chemistry happens.” (Seriously, put that in the search bar at the top of the page and you’ll see how much I use it.) If you combine castile soap, or any true soap, and vinegar, they will react with each, break each other down, and you will end up with neither soap nor vinegar. Instead you will have an oily, gunky mess. The only impact this might possibly have on weeds is to smother them, but it would be so unsightly in its gloppiness, that I think I’d rather have the weeds.
Stopping weeds before they start: The best strategy is prevention
Maybe because I consistently was positioned at left defense throughout my youth soccer years that I love a good game of defense. Defense is an excellent approach to weed control. Preventing weeds from growing saves so much time in battling them afterwards.
Plant thickly – Use dense planting to crowd out weeds
The technique of planting densely is all about taking sides in the constant battle between species. If we plant desirable plants close enough together so that they touch, then the weeds will not have soil space or sunlight to be able to thrive.
Planting ground cover for weed prevention
Similar to planting densely, a cover crop beats weeds at their own game. You get to choose what plant you want to cover the ground. Planting a ground cover not only crowds out weeds, but it protects the ground from water and nutrient loss from the sun and wind. It also protects the ground from erosion. There are many many options for ground cover – legumes are a great one to use for building up nitrogen in the soil. In my area, jasmine and myoporum are popular options. This is a chat for your local knowledgeable master gardener or nursery to find out what grows best where you are.
Watering wisely to keep weeds from invading
Plants thrive with water, so to discourage weeds from growing, water your plantings strategically. Using broad sprayers that water wide swaths of ground will encourage wide swaths of weeds. Instead, explore the many options of drip lines, soaker hoses, and other targeted irrigation techniques so that you are watering directly on the plants you desire to grow. Needless to say, in rainy areas, this is irrelevant.
Mulching for weed control
There’s nothing like a thick layer of mulch for blocking weeds. Once I learned the virtues of mulching, I had a fantastic new advocate in my garden. Not only does mulch suppress weeds, it also protects the soil from nutrient and water loss, adds fertility, and is beautiful.
There are many types of mulch available, each with their own advocates, but I strongly encourage you to use an organic mulch rather than a synthetic one made from rubber. The organic mulch will add the nutrients to the soil, whereas the synthetic one will not. I’m a particular fan of the aptly named gorilla hair mulch because I love how it holds on to itself and forms a dense mat. Not only does it keep water in and weeds out, but it also forms a very comfy mat to walk and kneel on in my garden.
When it comes to mulch, don’t be skimpy. Weeds will laugh at a too thin layer of mulch and grow right through them. If you’re going to lay down mulch, aim for 3-4 inches. This may seem like a lot up front, but it will save you copious amounts of time and energy by doing so much work for you over the year.
Landscape fabric for weed control
Landscape fabric is intended to keep weeds out while allowing water through. It’s a topic of debate, but I think if you manage your expectations of landscape fabric, it can help against weeds. Landscape fabric comes in wide rolls from the garden center. It is not a terribly attractive substance, but it’s meant to be used under coverings like gravel or mulch. It gets a bad rap because weeds can grow in mulch on top of the landscape fabric, but I can assure you that their roots are not deep and they are super easy to pull out. I have laid down landscape fabric along the paths of my vegetable garden and covered it with 3-4” of gorilla hair mulch. The mulch is now beautifully compressed, and it is really a lovely springy surface to walk or kneel on. Landscape fabric will not keep out weeds completely, but it is a great help.
The most targeted weed control of all: physical removal
This is by far the least sexy and least trendy way to control weeds. But nothing beats getting out there and removing the weeds by physical effort. There are a number of failsafe methods.
Hand pulling weeds: How to pull weeds so they don’t grow back
You were hoping I wasn’t going to say this, but it is unavoidable. Hand pulling weeds checks every box when we’re looking for safe, effective, non-toxic weed control. All it costs is hard work.
The key is to find some good tools that work for you. I’m a fan of a cultivator and a trowel.
Hand pulling weeds is truly the best method in densely planted areas. You don’t want to spray these areas with anything that might harm desirable plants—not even boiling water. The key is to find some good tools that work for you. I’m a fan of a cultivator and a trowel. I wear them in my gardening tool belt like two holsters. (Cue wild west music.) I use an old foam bed pillow to kneel on (those 1” thick garden kneelers just don’t do it for me.) I identify a goal area for the day and get to work. It’s a fantastic time to listen to a book or cycle through your five senses and be present in the moment. It’s a time for meditating, philosophizing, and patting yourself on the back for tackling something hard.
A few tips for making hand pulling weeds easier and more effective:
- Extract the whole root. This ensures that the weed will not grow back.
- If possible, wait until there’s been a rain, which will loosen the soil and make pulling weeds easier.
- Don’t pull at the top of the plant, which will break the plant off at soil level, but rather use your tool of choice (for me a cultivator) to loosen around the roots so you can pull out the whole thing.
- Get them small. It is much easier to pull small weeds than large ones.
Practice constant vigilance. A gardener’s work is never done, especially when it comes to weeds. Spending a little bit of time regularly pulling weeds will save you a backbreaking session later.
There’s nothing like a good hoe: The best tool for weeding faster
Dutch hoes, draw hoes, ridge hoes, heart hoes, field hoes, scuffle hoes, diamond hoes…there are many different types of hoes, and I can guarantee that every ardent gardener will have a strong opinion on which one is best, as I do. Certainly, there are different ones for different specific weeding situations, and others have regional associations.
For the type of weeding I do most, which is clearing weeds off of our hard-packed native soil—little more than compressed decomposed granite—there is nothing like a hula hoe. A hula hoe also gets called a stirrup hoe, or even more generally, a weeding hoe (though most hoes are for weeding). This is a super way to get your workout. Make sure your hoe is good and sharp. Lay the blade at about 45 degree angle, hold your core tight, and push and pull the hoe across the ground.
Rototilling as natural weed control – Pros & cons
Rototilling weeds is a method of chopping up weeds and burying them in the soil. It can clear a section fairly quickly of weeds. However, this method has some drawbacks. For one, it basically assists the weeds by planting their seeds in soil that is loosened and easy to grow through. Secondly, rototilling wrecks havoc on the structure of soil, disrupting the microbiome the productive soil needs, causing nutrient-loss by exposing them to the air and dehydration, and even sending some soil airborne.
Rototilling can be useful if you have planted a cover crop to build up the nutrient density of the soil. Especially with a field of legumes, which fix useful nitrogen back into the soil, tilling this into the soil can boost the yield of future crops. Even here, though, take care to till shallowly so that you don’t disrupt the soil. The nutrients will still filter down into the soil without a deep tilling.
Other natural weed control methods
What is sheet mulching and how does it kill weeds?
Sheet mulching is also called lasagna gardening because of its many layers. It is a great way to kill weeds and build up soil nutrients at the same time in preparation for planting a new garden area. The principle is to layer different types of beneficial matter over an area and let it sit. The benefit of this method is two-fold: it’s pretty low-work and it creates good soil. The downside is that it can take a while, like three or four months, so plan ahead.
How to Sheet Mulch Step by Step
- Start by cutting the plant matter low but leave the clippings on the ground.
- Then sprinkle a layer of soil amendments, like blood or bone meal.
- Next, lay out cardboard or a thick layer of newspapers, overlapping the edges so nothing can grow through. Choose paper or cardboard with little colored ink and no glossy coatings. Remove packing tape and labels as well. Hold down the edges with pavers, rocks, or sandbags so wind or wayward puppies don’t run off with them.
- Wet this layer thoroughly with a hose.
- Cover this with 2-3 inches of nitrogen-rich compost—that means the moist, dark brown compost made of decomposed manure, vegetable scraps, fresh grass clippings.
- Then layer on carbon-rich compost—that’s the dryer light brown compost made of dried leaves, straw, pine needles, or sawdust. Alternate these layers until they are 12-18 inches thick. See what I mean about lasagna layers?
- Wet all the layers down again with a hose, and you’re done!
Give this several months to decompose. If your weather is dry, spray this down occasionally to keep all those microbes alive and actively decomposing everything. By the time you’re ready to plant, all those nutrients will have melded together, smothering the weeds, and creating an excellent start for your garden.
Tarping & solarizing weeds – Using sun & darkness to kill weeds
Tarping or solarizing is another technique if you want to clear a swath of ground quickly. It is simpler and faster than sheet mulching and doesn’t use any chemicals, but also this does not build up the soil health. Simply spread a tarp or thick layer of newspapers over the ground, weigh down the edges, and let it sit for two weeks. The heat of the sun combined with darkness will kill the weeds beneath.
After two weeks, check under the tarp to see how the process is going. Don’t leave the area covered any longer than needed. Left too long and the valuable life in the soil could be harmed, or the tarp could begin to break down and deposit microplastics.
Flame weeding: Using a weed burner to kill weeds naturally
A flame weeder uses fire to burn away weeds. It is targeted and chemical free. Because of the risk of wildfire where I live in San Diego County, I have not tried this method out. But if you live in a more humid climate, it may be an option for you. Please take care to learn how to use the device carefully before you begin.
Mowing for weed control
Half of my property is an empty one-acre field. Over the 20 years we’ve lived here, there have
been numerous brainstorms for “what to do with it.” A soccer field, a horse pasture, a cultivated meadow filled with meandering paths. As it turns out, we’ve never done anything with it, and I don’t think we ever will. All of those plans take an exhaustive amount of effort, time, and most precious of all around here, water. So the acre has just sat there, left to its own devices, growing whatever it pleases. It’s a great space for the dogs, remote control cars, and kite flying.
However, we do exercise one key weed control method: we mow it monthly with our lawn tractor. Mowing this field regularly as a means of controlling weeds has several benefits:
- Keeps fire-prone dried brush to a minimum.
- Prevents the plants from producing their unique form of pointy, sticky, or barbed seed that end up in my dogs’ coats, or worse, in their ears.
- Keeps the plants on the soil, holding it down and preventing erosion from wind or rain.
- Keeps nutrients in the soil, especially because we leave the clippings on the ground, which will be a benefit to any planting efforts anyone in the future might want to undertake.
And in the spring, when the weeds are lush, mowing it makes the field look like a gorgeous grassy lawn but without any of the intensive inputs.
Unexpected natural weed control methods
Using chickens & goats for natural weed control
Goatscaping. I have just had the joy of learning that word. As you might deduce, it is the use of goat herds to curb weeds. Did you know there are places where you can rent a herd of goats? Chickens do similar work. The drawback to both is that they are completely nondescriminating in what they eat, but the bonus is that their droppings will nourish the land. If you have a densely weedy areas and can find yourself some chickens or goats, give it a try. To be honest, I haven’t utilized this method yet. For one, other methods have been sufficing, and secondly, I cannot imagine with what exultation my two dogs would greet such visitors. I think they would be distracting, to say the least.
Edible weeds – The weeds you should be eating instead of killing
I hesitated before writing the phrase “edible weeds” because as soon as you want a weed, it ceases to be a weed. But setting philosophy aside, there are quite a number of so-called weeds that are perfectly edible plants. When I have subscribed to a CSA farm box (Community Supported Agriculture) where you get what’s in season, there would be times I’d find a bunch of greens in the box I didn’t recognize.
I soon learned they were dandelion greens, or purslane, or sorrel. These all get called weeds, but they are all completely edible. So, take a moment to see what’s growing in your area, and you might have grown your dinner salad without even knowing about it. Be sure the greens haven’t been sprayed with any pesticides or herbicides before you start munching, but otherwise, give them a good rinse and spin, and your dinner is almost ready.
Understanding beneficial weeds
There’s another class of so-called weeds that bring additional benefit to your yard. Clover is one. It is a great ground cover, which helps to keep soil moist and to crowd out other weeds. It also is attractive to bees, which you need if you’re trying to grow any form of flowering fruit or vegetable.
Natural weed killer FAQs
Is Homemade Weed Killer Safe for Pets?
It completely depends on what you’re using. With boiling water, you would want to keep pets away while you’re applying it, but there is absolutely no harm to pets afterwards. With any other substance, such as soap, salt, baking soda or the like, if a pet ate them, it could cause some distress.
How do you stop weeds from growing?
The best way to stop weeds from growing are to block them with dense plantings, ground cover, mulch, or landscape, and by targeting irrigation.
What is sheet mulching?
Sheet mulching is a technique that creates a weed-free patch by layering different materials and letting it sit for several months. The layers include soil supplements, bare cardboard or thick newspaper, moist compost, and dry compost. Keep it regularly moist.
Can I use homemade weed killer in a vegetable garden?
No, in a vegetable garden it is best to discourage weeds with mulch and to hand pull or hoe weeds.
Does boiling water kill weeds permanently?
Boiling water can kill small, tender weeds completely, but large weeds with deep roots would need another method.
How do you stop weeds from growing through mulch?
Mulch stops weeds from growing through if it is laid thickly on the group. Three to four inches of mulch is best.
Putting it all together
The key takeaway I want to leave you with is that weeds can definitely be controlled without toxic herbicides, but you need a multifaceted approach. There is no natural weed spray that will do it all for you. It is a combination of prevention, redirection, targeted spraying, some hand pulling that will win the day. Fortunately, once you have some measures in place, such as dense plantings, ground covers, mulching, and strategic irrigation, the weeding work gets a whole lot easier. A little investment of time and effort at the outset will save a tremendous amount of time and effort down the road and will result in a much healthier outdoor space for you, your loved ones, and the earth we call home.
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