:max_bytes(150000):strip_icc()/GettyImages-2148772135-50fb311090604458a0a50ba20c123e64.jpg?ssl=1 "Tired of Weeds? Try This Quick Soap-and-Water Fix Before Buying a New Cleaning Product")
Key Points
- A simple homemade weed killer using dish soap and water can dry out and kill unwanted plants by breaking down their protective leaf coating.
- For tougher weeds, adding vinegar boosts the formula’s potency, with the acetic acid helping to rapidly dehydrate and destroy the plants.
- Timing is key: apply the solution during hot, dry, windless days to avoid harming your garden plants and to ensure the mixture isn’t washed away.
It has been said that the two things in life we can be certain of are death and taxes. If you are a gardener, a third inescapable menace confronts you: weeds. Many gardeners have concluded that, if they must battle weeds, at least they will seek herbicides that are inexpensive and relatively safe for the environment.
Enter the use of dishwashing soap to prepare an herbicidal solution. And dish soap has an added advantage: You probably already have it in your kitchen.
How to Mix Dish Soap Solution and Why It Kills Weeds
The only preparation needed for this project is gathering the following three items:
- 1 tablespoon liquid dish soap
- 1 quart of water
- A spray bottle to hold the formula
Shake it thoroughly before use. Why is it that something as harmless (to us) as dish soap can kill weeds? Dish soap contains solvents that break down the waxy layer that covers a plant’s leaves. Once it is broken down, the leaves will dry up, and the plant will die.
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Warning
While dish soap does have herbicidal properties, a lot has to go right for it to work, because many variables are in play. Factors include:
- Getting the proportion right in mixing
- Detergent strength of the dish soap
- Proper application
- Picking the right weather for spraying
- How strong the weed is. Some types of weeds die harder than most.
On the other hand, another pitfall is accidentally getting it on your garden plants: The solution might kill them.
Should You Make Vinegar Part of the Mix?
Many home remedies to deal with weeds include vinegar as an ingredient in their herbicidal solutions. Vinegar works the same way as soap to kill weeds: The acid it contains (acetic acid) removes the moisture from weeds. Once dried out, they die.
Vinegar’s herbicidal action is more powerful than dish soap’s; for maximum potency, buy the “horticultural” type, which is 20-30 percent acetic acid. If you try the soapy solution discussed in this article and find it’s not getting the job done for you, your next step should be to add vinegar to the mix. Here are the proportions:
- Four parts vinegar to one part water
- 1 ounce of dish soap to a gallon of the mixture (in this case, the soap serves as a surfactant)
How to Use Dish Soap Solution to Kill Weeds
Since the dish soap acts to dry out the weeds, help this drying action along by consulting the weather forecast and selecting the optimal time for application. Choose a hot, dry, sunny period to spray the soapy solution on the weeds.
Avoid spraying if rain is in the forecast, because the rain would wash the solution off the weeds too quickly.
Also, pick a day with no wind, so that the spray does not get on your garden plants. The spray will have the same effect on your garden plants as it has on the weeds: It will (potentially) kill them.
This is why insecticidal soaps are made with a milder type of soap than the soap used to kill weeds. When spraying, cover as much of the foliage as possible for maximum impact.
Science Behind the Soapy Solution’s Success
- The waxy layer on a plant’s leaves is known as the “cuticle.”
- This waxy layer is a protective coating: The cuticle helps the plant’s tissues avoid losing excessive moisture.
- Once the detergent action of the dish soap strips this layer off, the plant loses too much moisture to survive.