Managing weeds in the garden is a task that often brings a sense of dread to many gardeners. Hand-pulling them is time-consuming and repetitive, and many gardeners are wary of using chemical herbicides due to environmental and health concerns.
However, there are non-toxic herbicides available that can effectively control weeds in the garden, and one of them is table salt. While no herbicide can be considered entirely harmless (as their primary function is to eliminate unwanted plants), salt, or sodium chloride, is a natural alternative that can be effective against pesky weeds.
Can Salt be Used to Kill Weeds?
Indeed, salt can serve as an effective non-toxic herbicide. However, not all types of salt are suitable for weed control. It is crucial to use regular iodized or non-iodized table salt containing sodium chloride. Double-check the package to ensure you have the correct type, and avoid using magnesium sulfate (Epsom salts), rock salt, or sea salt for this purpose.
When applying salt as a herbicide, caution is essential. It has the potential to harm surrounding plants or leech into the soil, affecting its long-term health. Excessive salt usage can even lead to soil sterilization over time. Therefore, it is best used for treating weeds that are not surrounded by plants you value in the garden, such as those growing through cracks in asphalt, pavement, or between patio stones.
The Chemistry of Salt: How Salt Works to Kill Weeds
Salt, specifically sodium chloride, is an effective weed killer due to its ability to dehydrate plants and disturb the water balance within their cells. To ensure better absorption by the weeds, it is recommended to mix salt with water before application, as salt is water-soluble. However, it’s crucial to exercise caution when using salt as it is highly toxic to all plants.
For small-scale gardening or targeted weed control, salt can be a useful herbicide. Nevertheless, it should be applied carefully to avoid harming desired plants and to prevent long-term damage to the soil. When used judiciously and with attention to its potential side effects, salt can be an efficient and non-toxic option for controlling weeds in specific areas of the garden.
How to Use Salt as a Herbicide
Salt is most effective as a herbicide when it is mixed with water. The recommended strength of the saltwater mixture depends on where you plan to apply the herbicide. If you are targeting weeds in a garden bed with other plants you wish to preserve, it’s best to start with a weaker mixture, like a 1:2 ratio of salt to water.
However, if you are using salt in an area where the long-term health of the soil is not a concern (such as between patio stones or cracks in driveways), a much stronger mixture can be made, like a 2:1 or 3:1 ratio. Keep in mind that such strong mixtures will significantly impact the soil’s pH levels over time and may lead to soil sterility.
To apply the saltwater solution, target the foliage of the weeds and avoid soaking the roots to protect the surrounding soil and plants. You can use a spray bottle or pour the mixture from a container. If there are other plants nearby, generously water them after applying the herbicide to flush out any saltwater that may have reached the surrounding soil. However, it’s not advisable to use the saltwater treatment in tight-spaced flowerbeds or vegetable gardens to avoid unintended harm to desirable plants.
Salt vs. Other Non-Toxic Herbicides
There are several other ‘non-toxic’ herbicides that are popular among home gardeners. Each option has its benefits and disadvantages, and the effectiveness may vary depending on the situation.
Household vinegar is one option, but horticultural vinegars with higher concentrations of acetic acid are more effective. When mixed with salt and water, these vinegars have the potential to control weeds well. Like the salt and water mixture, vinegar must be applied carefully to avoid altering the pH balance of the soil, which could affect future plant growth.
Boiling water can also be used to some extent. It works well for dealing with clusters of stubborn weeds in a garden bed, as it has no residual effects on the soil. However, as with other herbicides, boiling water must be applied carefully to avoid damaging desired plants.
Surprisingly, fire is another ‘non-toxic’ method of weed control used by gardeners. Flame weeders burn the emerging weeds, causing structural damage. While this method permanently removes annual weeds, it may not kill the roots of hardier perennial weeds. Flame weeders can be purchased online or at most garden centers or nurseries.