DIY Non-Toxic Weedkiller That Works

There are situations where you want certain plants dead, but hand weeding is difficult or counter-productive because it will bring fresh seeds to the surface to germinate. This may be a situation for an herbicidal spray. I approach this topic with hesitation, because some of you stopped reading at the second sentence and are right now composing long ranty hate-emails describing how I am worse than BP and Monsanto put together to even suggest folks use herbicides.

But hold up a moment. I’m not saying it’s time to break out the Round-Up. That stuff’ll kill you. Well, more accurately, it’ll kill your cells, but really what are you if not a collection of your cells? I’m saying that there can be a time and a place for responsible herbicide use. And responsible means non-toxic. (Well, except to weeds. Obviously you want something toxic to weeds. That’s the point.)

I don’t have a lot of areas in my yard that benefit from herbicidal sprays – weed management at my place is mostly smothering. I throw cardboard and wood chips on everything and that really minimizes my weed burden. The few weeds that do grow in heavily mulched bed are typically very easy to hand pull.

But once a year or so – typically in Spring – I’ll whip up a batch of DIY herbicide from non-toxic ingredients I already have around the house. I’ll spray down the gravel patio and prevent newly germinated annual weeds from growing into a bigger problem. A sprayed-on natural weed control option can be particularly useful for compacted areas like patios, pathways and gravel driveways.

Weed Killer

DIY Non-Toxic Weedkiller

This is the recipe I use. It’s similar to organic herbicides like Burnout II or Avenger but with a far more appealing price tag. I typically make a quart at a time (four times the recipe below) which fills one professional-sized spray bottle. You can scale the recipe as needed.

Ingredients

  • 1 cup homemade citrus cleaner concentrate, undiluted. (See link for full directions. The brief version is, soak citrus peels in white vinegar for several weeks, until vinegar has strong citrus aroma, then strain.)
  • 1 tablespoon citric acid (available at homebrew stores or online)
  • 1/4 teaspoon liquid dishsoap (environmentally friendly/non-toxic strongly preferred)

Method

Combine citrus cleaner and citric acid in a spray bottle. Secure lid on spray bottle and shake until the citric acid dissolves. Add in dish soap, replace lid, and gently flip bottle a few times to incorporate soap without creating a mass of bubbles.

How It Works

The white vinegar base contains acetic acid, but at the typical 5% acetic acid concentration, household vinegar alone isn’t particularly effective as a weedkiller. The citrus peels are important – they contribute the essential oil d-limonene to the vinegar. D-limonene is what makes commercial orange cleaners such powerful grease-cutters! That same property strips the cuticle (protective coating) right off the leaves of the weeds and lets the acidic ingredients burn out the foliage. The citric acid is there to boost the burnout capacity of the acetic acid and the soap helps the other ingredients stick to the leaves long enough for the weed killer to work.

How To Use This Spray

This spray works best applied to areas of new annual weed growth while weeds are still fairly small and actively growing. Spring is the perfect time to take preventative action. Wait until you get a hot, sunny day (as hot and sunny as your area can manage) and are confident you won’t see rain for several hours. You want the weeds you are targeting to be actively transpiring, with open pores on their leaves. Cover the weed thoroughly with the spray, making sure to coat the leaves and the central growing point of the weed.

What It Will Do

This is a non-selective, contact herbicide, which mean it will kill pretty much anything green it touches, assuming you apply it as directed. It is most effective on young, annual, broadleaf weeds.

Weed killer

What It Will Not Do

This will not stop new weeds from germinating and growing. It will not provide good control to hard-to-eradicate perennial weeds. This is not a magic bullet for weeds like bindweed, creeping buttercup, horsetail, or bermuda grass. Unlike translocating herbicides like Round-Up (glyphosphate) this DIY herbicide will not move from the leaves into the root system. Plants with aggressive, energy storing root masses will tend to bounce back from this spray. Sorry about that, but I want to set your expectations accurately. If you are diligent about a regular repeat-spray program, you will eventually weaken the root system of pretty much any plant, but honestly, in hard cases a garden fork and digging is probably the best non-toxic way to manage difficult perennial weeds.

Cautions

Citrus essential oils like d-limonene can be dangerous to cats. If you have cats you might want to keep them away from the treated area for several hours after you apply this spray. Since this spray is used in an outdoor setting with lots of air circulation, I think this it is unlikely to harm kitties, who will avoid strong citrus smells naturally (commercial cat repellant products often contain d-limonene for this reason). Use your own best judgement and never, ever spray something like this directly on a cat.

This herbicide is non-selective. If you spray this on your vegetable seedlings or other things you like, you’ll kill them. So be careful. Work on a still day, and don’t be sloppy. Be careful along property lines so you don’t harm your neighbor’s plants. Consider that, while this weedkiller isn’t toxic in a general way and doesn’t poison the soil like many herbicides, it’s going to be irritating as hell (or worse) to any little ground critter who gets coated with it. Think of the worms, people!

Comments

  1. Greetings from Buffalo!

    Great post. My husband loves Round-Up, but like you said, it’s going to kill us (not to mention the kids, dachshunds and cats!)

    I’ve glad you mentioned that hand weeding can spread weed seeds, causing just more work in the long-run. Now I can justify just not doing it!!

    I also read this year, not to till up the soil (on anther blog) because that also spreads weed seeds. The article said to just leave it….and plant. Do you agree? It would be great to avoid that chore too, not to mention borrowing my neighbors tiller. But I’m hesitate. I’m a tiller and just want to do the right thing!

    Thanks!

  2. dr. Dave says:

    Another excellent article. I’ve used straight white vinegar for years – the aroma reminds me of an Italian salad. But I really need to find 10 to 20% vinegar acidity if possible. Meanwhile, I’ll try your spray and perhaps follow it up a few weeks later with a straight vinegar dousing or two. Thank you.

  3. dr. Dave says:

    A follow-up tip…an accidental straight white vinegar application can be immediately neutralized with a thorough water dousing. Let the area dry completely before reapplying the weed killer.

  4. I was able to locate ag vinegar in 5 gallon buckets. We tried spot spraying with some success but my husband was determined to get rid of a patch of Canada thistle so he used a sponge craft brush and “painted” each plant by hand last fall. So far (hope I don’t jinx this) that process worked very well. Timing and persistence is key with weeds. It’s worth the research to ID the weed you’re trying to rid (know your weed and growing habit).

    • You can usually get rid of thistles by chopping them off at ground level. Some thistles are biennial, so that plant may come back the next year, but if you chop it off again, it won’t come back. Use a round nosed shovel. You will slide the shovel along the ground and chop off the plant at ground level…of course it takes some muscle, and be careful to not miss and get your feet!

      We do this with musk thistle (since it is a noxious weed in KS) and other kinds of thistles as well. Much faster than painting them with herbicide. Make sure to do it before the flowers release their seeds. Also, if the flower already has pink in it, you may need to pull the flowers off the plant, as the plant has enough energy stored to mature the seeds.

      Here is how we do it: for musk thistle, if the plant has pink flowers but they haven’t started turning yet, chop them down, and then chop off the flower heads. In the pastures we just let the beheaded plants lie, but in your yard, probably you will pick them up. If the flowers have started turning brown, use leather gloves and pick them off and dispose of them before chopping.

  5. I’ve had great success with cardboard and mulch on our rental lot, too. My big nemesis is a brick patio (gorgeously set under an old grape vine) with all the cracks filled with very old dandelions. It’s a lovely spot for outdoor meals, if your legs aren’t buried by weeds. I can hand pull the weeds’ leaves in an hour, I can’t get to the roots without lifting the bricks. I’m guessing to do the whole area would take 5-10hrs, which is hard to motivate myself towards when I don’t wholly believe they’ll be gone for long. So, I’ve done some of this, but not much. We also tried torching the dandelions last year, to no avail. I also sprayed with vinegar (& now understand why it didn’t work). I have never been more tempted to use Round-Up in my life, but I WILL NOT. I just understand why people go there if they don’t understand the implications. Some weeds are so frickin’ frustrating!

    • What I recommend is, if the patio allows it, go to the thrift store and get a long, cheap knife. Something sturdy, but thin, like a carving knife. Slide the knife down along the root, as deep as you can safely wiggle it, to loosen the soil and, if necessary, cut the tap root below ground. This will be a pain in the ass, but it will weaken the roots a lot. In a few weeks, when the dandelions start regrowing, they will be smaller and less oomphy. Break out the spray. Make a big batch and keep it handy. Every 3-4 days, squirt the regrowth. The leaves will die but they will try to regrow. Squirt again. Repeat this as many times as necessary to exhaust the root system. This IS possible. It just takes perseverance.

  6. Another great non-toxic weed killing tool is the weed dragon! We use it after a rain to kill weeds on stone paths, barkdust, garden beds, etc. And you feel pretty bad-ass with a propane torch!
    https://www.flameengineering.com/products.php?category_id=2

    It is an investment, but we now share it with all our neighbors who pitch in for propane. :)

  7. nancy sutton says:

    Thanks a million!! I’m going to try this for the carpets of shotcress, chickweed, herb Robert, nipplewort, etc. annual seedlings (until I have to chickens to harvest them for ;). But, for my nemesis, bindweed, my latest plan is to distribute a dozen cheap scissors around the yard (that’s how many patches I have!), so snipping off the endless new shoots is always easy and convenient. Even horsetail is easier to pull, and quack grass can be satisfyingly dug out…. and/or smothered. But bindweed!! I do have to chuckle, though, at it’s eager ambition to take over the world….

    • Nothing about bindweed makes me chuckle – I admire your positive attitude. :) This spray will do a good job on the other weeds you mention. Chickweed self seeds like crazy, so I’d just plan on a second dosing to get the newly germinated weeds in a few weeks after initial spray.

  8. Thanks, I think I’ll give this a try. Up until now I’ve just been pulling everything out – which can be time consuming.

    • Poor Dandelions, they do have their attributes but in the wrong location they are such a chore to eradicate. For your situation (under bricks) I believe there is now a brick patio sand/polymer ‘sealant’, to fill in the gaps much like a tile grout sealant. Once ALL the weeds have been eradicated in the spring, you can apply the sealant. Hope this helps!

  9. The thing you said about cats avoiding citrus smells got my attention. We have a cat, and she has already destroyed a couple of plants I had started in my room (bellpepper, basil, and chives, but she left the tomato starts alone.) so now I have to keep her out of there, which I don’t like to do, because I kind of like her (when she isn’t destroying my plants.) Do you know of a citrus spray I could put on my plants that won’t kill them, but might possibly keep her away?

    • I’d look at any of the commercially available cat repellant sprays (or a search will turn up homemade options) and spray them around the area instead of on the plant itself. Like, maybe spray the area around your plants, or spray a piece of paper with a repellant spray thoroughly and stick that in the pots with a chopstick like a flag.

    • We have a huge outdoor cat problem in my neighborhood (well it’s a nuisance to me since they poop all over my yard!). I have tried everything. This year I’m finally onto something that seems to be working. Plastic takeout forks all over my beds. I push the handle side into the ground, the tines angled out. Perhaps you could do this on indoor starts too, just angle the forks out of the containers? Worth a try!

      • I have had that problem too Amber, a neighbor who feeds feral cats. And because they don’ t poo where they eat, let’s just say it’s been a problem… I’ve successfully used those ‘high pitched’ cat deterrents for a few years now. Of course this won’t work it you have animals in the yard as pets. I’ll try your plastic fork idea in my container pots, thank you!

      • We also had a cat issue in our raised veggie beds and found that chicken wire with wide openings (approx 3 inch or so) worked well. The plants grew up through the openings and the cats couldn’t stand walking on it and certainly couldn’t dig in it. I also kept a squirt bottle handy…

      • Hi, have you tried cinnamon powder? Just sprinkle around, it will keep cats and rabbits away!

    • Try just putting citrus peels in your plants. We had good luck spreading them over a raised bed to keep the cats out of it.

  10. Do you think you could substitute orange or lemon essential oil for soaking the peels? I know they contain d-limonene. I’m thinking about the time savings if you need to do it NOW!

    • Yup, you sure could. I don’t know exactly how much you’d add, but I’d think a fair bit – maybe a teaspoon? I think you could also add another solvent to the mix, like rubbing alcohol. I haven’t tried this but I’d expect it to do similar things in stripping the cuticle of the plant.

  11. Boiling water works wonders to kill weeds. A great way to use that boiling water from processing foods in water bath canning.

  12. We are constantly fighting nut-grass (nut-sedge) and some onion chives that threw off seeds and keep coming up in my flower bed? Will your potion work on either of them – hate to use Round-up, too

  13. I raise bees and I have been looking for something that won’t harm my bees. I have tried the vinegar and Dawn dish washing detergent weed killer and that did not seem to have any affect on my bees but it made my yard smell like vinegar for a few days.

    The citrus smell would be much better than vinegar. I just hope it doesn’t attract my bees and then kill them or repel my bees and make them leave the hive and go somewhere else.

  14. my understanding is that you do not want to use regular household vinegar for this, it is not strong enough. You need to buy vinegar from a landscape supply company or Online, I think it is 10 percent concentrated.

  15. I wonder–what will this do to fire ants? I’m going to make some and try it.

  16. If you don’t have weeks to make citrus cleaning concentrate — wondering if you can purchase somewhere?

  17. I was using white vinegar with dish soap. It worked.
    My gardener came up with: 1 gal white vinegar, 2 cups Epsom Salts & 1/4 cup Dawn (blue/original).
    Worked great on the weeds.

  18. Re: keeping weeds down, and making new beds with the PC method….I make all my beds with my PC method, paper and compost. I lay overlapping sections of newspaper over the area of turf that I want to turn into a bed. I place any kind of compost, grass clippings, leaves, bark that I can lay my hands, on top to weigh the papers down and to hide the paper itself. The turf dies off, and then the roots die off, and then I have soil for planting. No digging, no bad backs. I have used this method for 40 years. This method also works to kill off weeds in beds, too. I also use newspaper sections around the base of tomatoes plants. Keeps the weeds away, moisture in, and a cool root run. Paper was once trees, the ultimate in recycling.

Trackbacks

  1. […] Sometime, I might also try this DIY Weedkiller from NW Edible. […]

  2. […] This works absolutely great and it’s completely safe for gardens with children and pets.  It can be made in minutes by mixing citrus cleaner concentrate (made by soaking citrus peels in white vinegar) with citric acid and liquid dish soap.  Find out more about this great recipe HERE. […]

  3. […] This works absolutely great and it’s completely safe for gardens with children and pets.  It can be made in minutes by mixing citrus cleaner concentrate (made by soaking citrus peels in white vinegar) with citric acid and liquid dish soap.  Find out more about this great recipe HERE. […]

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