Homemade Herbicide: How to Use White Vinegar, Washing-up Liquid and Salt for Weeds

In many Brazilian homes, tending plants and looking after the garden has taken on a different approach. Alongside watering, pruning and arranging pots, many people are looking for more natural ways to tackle the persistent weeds that keep appearing. Rather than relying solely on chemical weedkillers, homeowners are turning to a simple homemade herbicide made from kitchen staples: white vinegar, washing-up liquid and salt, used to control unwanted plants in specific parts of the garden.

How does white vinegar work as a natural herbicide in the garden?

White vinegar is the main ingredient in this mixture because of the acidity of its acetic acid. It works on exposed parts of the plant, including leaves and young stems, by damaging cell structures and speeding up water loss, which quickly dries out the treated area.

The acetic acid concentration in standard shop-bought vinegars can already affect smaller or more delicate plants, particularly when treatments are repeated. As it is a contact herbicide, it mainly acts on above-ground growth and does not always destroy the roots completely, so further applications may be needed if new shoots emerge.

How can you prepare a white vinegar, washing-up liquid and salt mixture safely?

The recipe contains three basic ingredients: a larger amount of white vinegar, a small quantity of mild washing-up liquid and some table salt. A common proportion is around 3.5 litres of vinegar, one tablespoon of washing-up liquid and one cup of salt, for treating heavily weeded areas on pavements and between paving joints.

The washing-up liquid acts as a surfactant, allowing the vinegar to spread more evenly and stick better to leaves. Salt, meanwhile, works as a desiccant by drawing water from plant cells. However, excessive amounts can damage the soil, so it is better suited to places where nothing is intended to grow afterwards, such as pavement cracks and gaps between slabs.

How should the vinegar herbicide be applied effectively?

Once the ingredients have been combined, many people pour the liquid into a garden sprayer or spray bottle for more precise use. Shake the container thoroughly before each application, then spray it directly onto the weeds, wetting the leaves and young shoots to maximise contact.

To use it routinely while avoiding problems elsewhere in the garden, follow a few basic guidelines:

• Treat only the weeds that genuinely need to be removed.
• Avoid spraying lawns, vegetable patches and ornamental plants you want to preserve.
• Choose dry days with no rain forecast for the following 24 hours.
• Repeat the treatment if the plants begin growing again after a few days.

What environmental and safety precautions are needed when using vinegar?

Although it is a simpler alternative to many commercial products, vinegar still needs to be used carefully around soil and neighbouring plants. In mixed beds, it may be preferable to apply it using a tightly directed spray, a brush or a sponge, preventing splashes from reaching healthy, sensitive plants.

Salt build-up is another important consideration. In cultivated areas, many people reduce the amount of salt or leave it out altogether, accepting that more frequent treatments may be necessary to avoid harming future roots. Wearing gloves and clothing that covers the skin, as well as keeping the mixture away from children and animals, helps keep the garden well maintained while using this homemade option as a practical aid for weed control.