Dealing with weeds in the garden is a task that most gardeners dread. Pulling weeds by hand is time-consuming and repetitive, but many gardeners also want to avoid commercially available chemical herbicides because they pose both environmental and health risks.
That being said, there are non-toxic herbicides that can be used to effectively control weeds in your garden, namely table salt. While none of the herbicides can be truly “harmless” used in the garden (after all, their main purpose is to kill unwanted plants!), but salt (or sodium chloride) is a natural solution that is effective at removing pesky weeds.
Can Salt Be Used to Kill Weeds?
In short, salt is an effective non-toxic herbicide. However, not all salts are created equal when it comes to weeding. Regular iodized or non-iodized table salt must be used. Check the packaging to make sure you’re using sodium chloride and not magnesium sulfate (Epsom salt), rock salt, or sea salt.
Salt must be used with care when using it as a herbicide. It can easily kill surrounding plants, or seep into the soil and affect its long-term health. Too much salt can even deactivate the soil over time. As a result, it may be most effective for dealing with weeds in your garden that are not surrounded by plants you care about, such as those that stick out of the asphalt or cracks in the pavement, or that grow between patio stones.
Chemical Properties of Salt: How Salt Kills Weeds?
Salt (sodium chloride) kills weeds by dehydrating plants and disrupting the water balance inside plant cells. Since salt is water-soluble, it works best when mixed with water, as it makes it easier for weeds to absorb. Sodium chloride is highly toxic to all plants, so care must be taken when using it. In general, salt is best used as a herbicide for small-scale gardening or weed control.
How to Use Salt as a Herbicide?
Salt is most effective as a herbicide when mixed with water. The recommended concentration of the brine mixture depends on where you plan to use the herbicide. If you’re applying salt to weeds and other plants in your garden bed that you don’t want to kill, you should start with a mixture of lower concentrations, such as a 1:2 salt and water mixture.
Alternatively, if you apply salt in areas where long-term soil health is not an issue (e.g., between patio stones, driveway cracks, etc.), you can make a stronger mixture, such as 2:1 or 3:1. The amount of this salt will definitely affect the pH of the soil over time and may cause the soil to become sterile.
The saline solution should be sprayed directly on the leaves of the weeds. Avoid soaking the roots with the mixture to protect the surrounding soil and plants. The brine can be sprayed with a spray bottle or poured out of a container. If there are other plants nearby, water generously after spraying the herbicide on the weeds to wash away any salt water that has entered the surrounding soil. In flower beds and vegetable gardens where space is limited, salt water treatment is not recommended.
Salt with Other Non-toxic Herbicides
There are several other “non-toxic” herbicides that are popular among home gardeners. Each has its own advantages and disadvantages, and there is no one-size-fits-all solution.
Household vinegars are an option, although they are not as effective as horticultural vinegars that contain higher concentrations of acetic acid. These vinegars, when mixed with salt and water, provide good weed control. As with salt and water mixtures, vinegar must be used with care, as it can alter the pH balance of the soil over time – affecting future plant growth.
Boiling water also has a certain effect. Boiling water is a great option for dealing with hard-to-remove weeds in your garden because the water does not have a residual effect on the soil. However, as with most other herbicides, you need to be very careful when applying boiling water to your garden so as not to damage plants that you don’t want to kill.
Surprisingly, fire is another “non-toxic” method of weeding used by gardeners. The fire burns off the newly grown weeds, causing structural damage. While fire control can permanently remove annual weeds, it won’t kill the roots of more tenacious perennial weeds. Flame weeders can be purchased online or in most garden centers or nurseries.