Homemade weed killer sprays not only help you kill all the bad weeds in your garden, they also save you money – and without the use of toxic chemicals.
While some weeds can actually be very good to have in and around your garden, many will steal nutrients from the soil that your crops, herbs, and medicinal plants need in order to thrive. Pulling weeds by hand to remove them is constant and back-breaking work.
Unfortunately, all that work can be in vain because many varieties of weeds possess very deep roots. Many times, what you are pulling is just the visible surface weed, leaving the roots intact in the ground, free to continue thieving nutrients from your crops.
Chemically manufactured weed killers can take care of your weed problem, but they may do more harm than good. Potentially harmful chemicals in popular weed killers, like those in Monsanto’s Roundup Ready that have recently provoked health lawsuits, may cause damage to the human body, honey bees, beneficial insects, and the soil in your growing plots.
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Using natural or nearly natural ingredients to thwart weeds gives the gardener complete control over what is being sprayed or applied to the weeds, as well as what is being infused on the plants which they’ll be serving to their loved ones after the harvest.
Most of the homemade weed killer sprays on this list will cost less than $1 to make, and you’ll have enough to treat several large garden rows of weeds.
Top 8 Homemade Weed Killer Sprays
1. Salt and Vinegar
Mix 2 cups of table salt with 1 gallon of distilled white vinegar. Stir and/or shake vigorously to make absolutely certain the salt has completely dissolved in the vinegar.
Spray the entire weed, especially the stem, to get rid of the unwanted wild vegetation. Caution, salt “sterilizes” the dirt, so it is unlikely anything at all will grow in that space for an incredibly long time. Any vinegar used to kill weeds should be at least five percent acetic acid to be effective.
2. Baking Soda
Simply sprinkle baking soda directly onto weeds in the growing area. Apply liberally enough to fully coat the entire weed.
While the baking soda will not kill either harmful or beneficial bugs, it can kill or scorch plants. Carefully sprinkle directly onto the weeds on days when there is barely any wind and rain is not in the forecast.
3. Borax and Dish Soap
Mix 1 cup of borax with 1 gallon of distilled white vinegar and spray onto weeds.
This homemade weed killer works incredibly well, but I can only use it in growing plots that neither our domestic pets nor our livestock have access to. Borax is NOT boric acid, but it is toxic to animals when ingested…that is why I often mix it with sugar to attract and kill ants and mice.
As an alternative to borax, you can use 1 cup of standard table salt, it works almost as well. Again, make sure to spray on days without wind or rain to prevent the spray from reaching your crops, herbs, or medicinal flowers.
4. Newspaper and Cardboard
This simple gardening hack is entirely free if you are recycling (or upcycling) old newspapers and cardboard. Use a weed eater or your hands to pull the weeds and then put several layers of newspaper or a sheet of cardboard over the now vacant space. Shovel some mulch or compost on top of the newspaper or cardboard to hold it in place.
Both types of paper products will eventually disintegrate, but since both of them are quality composting materials (as long as the newspaper only has black and white ink) you are enriching your soil while protecting the crops.
5. Boiling Water
This homemade weed killer recipe is probably the simplest on this list, but it’s really only designed to rid raised beds or container plants of weeds due to the need to heat water to boiling and then tote it to the area to be treated before it cools.
Avoid splashing the boiling water onto plants when pouring; the boiling water will kill them as quickly as it will kill weeds.
6. Lemon Juice
The acid in the citrus juice will kill even the strongest weeds. Saturate the entire plant, paying particular attention to the stem area when spraying.
For particularly strong weeds, mix 1 part lemon juice with 1 part distilled white vinegar. Add 1 tablespoon of cooking oil or any carrier oil you have on hand to make this homemade weed killer recipe even more potent.
7. Essential Oil and Vinegar
Combine 1 tablespoon of either orange or clove essential oil with 1 cup of distilled white vinegar. Simply spray it on the weed, but again, be sure not to get it on your other plants.
8. Listerine and Water
Mix 1 cup of Listerine with 1 gallon of warm water and spray onto weeds. This homemade weed killer also helps to ward off aphids.
What Makes Homemade Weed Killer Ingredients So Powerful?
There is good reason vinegar is at the base of a plethora of homemade weed killer recipes both here and all over the internet…it works.
Vinegar alone can work just fine on some weeds, but the addition of table salt, Epsom salts, or dish soap is often needed to kill particularly difficult weeds and Bermuda grass. You can use any dish soap, but I have had the greatest success when using Blue Dawn. I also use Blue Dawn dish soap as a base ingredient for many of my garden insect killer recipes.
The reason vinegar works so well to kill weeds (and likely insect pests, as well) is its acetic acid content. Most distilled white vinegar sold at grocery stores contains three to five percent acetic acid.
Acetic acid is a desiccant, meaning it removes moisture from what it touches. This acid is also the reason it is used to preserve food. When distilled white vinegar is prayed upon weeds, it draws all of the above ground moisture from the weed.
While the vinegar can also wreak havoc on roots, such a prime result should not be expected. If the weeds being sprayed have a wax coating or similar protective covering, a vinegar-based spray will not have as potent of an effect.
Whenever possible, use vinegar that has a 10 to 20 percent acetic acid content. While a concentration this high is usually not necessary to kill young or weak weeds, it can vitally boost your eradication efforts when treating tough and fast-growing weeds.
Apple cider vinegar can be used in weed recipes also, but it can be slightly less effective against strong weeds.
Common table salt has a sodium chloride base. This base ingredient is also a desiccant that will suck moisture from the stems and leaves of weeds – or any plant it touches. When vinegar and salt are combined in a homemade weed killing spray, you usually get astonishingly rapid results.
Oil cannot be used alone as a weed killer, as both salt and vinegar can, but it can be a valuable component to add to any of the DIY recipes above.
The oil breaks down the waxy and protective coverings on weeds and allows the vinegar and salt concoctions to work far more effectively. Once the protective coatings are stripped away, vinegar or salt (or both) cannot fully saturate the weed stems and help kill the unwanted vegetation.
When oil is added to a weed killer recipe, it thickens it. While this means that using an agricultural sprayer to deliver the solution to the weeds won’t be possible, it also means the ingredients will have far less runoff.
Delivering the weed killer recipe via a sprinkling can instead a sprayer should also help prevent any unwanted splattering onto your growing groceries just a few inches away. The longer the solution remains on the weeds, the better the chances are that it will soon be a dead weed.
Citrus Essential Oils
Using citrus essential oils (orange, grapefruit, lime, and lemon) will help “burn” or “scald” the weeds due to the natural acid they contain and their highly concentrated nature.
Dish soap–Blue Dawn, in particular–is at at the base of a multitude of effective homemade insect and weed killing recipes. Liquid dish soap cannot kill either on its own, but it’s an active and essential ingredient in DIY pest and weed removal recipes.
Blue Dawn, and most varieties of liquid dish soap, act as a binder for the other ingredients in homemade weed (and bug) killer recipes. Because distilled white vinegar is more effective at killing weeds when combined with salt, pouring a small amount of Blue Dawn into the mix will help meld all the ingredients together to increase the overall potency of the mixture.
The longer the solution remains on the weed, the better the vinegar and salt will work to dry them out and deprive them of nutrients.
Always mix any of the homemade weed killer recipes when you are ready to use them. The potency of the mixtures or even single ingredient weed killers, will diminish once they are exposed to air and sunlight.