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Garden Club of Cape Coral | Household remedies for weeds: How effective are they?

By JANETTA FOX - Garden Club of Cape Coral | May 16, 2024

When it comes to tackling weeds in your garden, you may be tempted to surf the Internet for household remedies. What you will find are numerous online recommendations to tackle unwanted weedy guests, with three of the most popular ones being vinegar, salt and boiling water. The question is: How effective are these options and are they safe to use?

Vinegar is a topical contact killer. Although a soaking of household vinegar having 5% acidity can kill small, shallow-rooted annual weeds, it is not particularly useful as a killer of pesky deep-rooted perennials. Vinegar will turn green leaves brown, giving the appearance that the entire weed is dead, but in a short amount of time new growth will appear. Recognizing that the product has limited effectiveness, you may now be asking yourself, “Why even bother using it?” Best to use your household vinegar as it is intended.

Note that the concentration of acidic acid needed to do an effective job on larger, mature weeds is much higher than the product you will find in your pantry. However, beware of purchasing horticultural vinegar having 20-30% acidity because the product will burn everything it comes into contact with, including yourself if not careful. It also has a negative impact on earthworms and beneficial microbes that work their magic in the soil. It is NOT recommended for home garden use.

How effective is your household table salt? Salt is a corrosive and will kill everything in the vicinity of application, hence its “scorched earth” reputation. It has a dehydrating effect on weeds and, if applied directly to the soil in a mixture with water, will kill the roots of unwanted plants. Unfortunately, it can also negatively impact desirable plants in the vicinity as water and rain often work to spread salt contents beyond the intended target. Over time and in sufficient quantities, salt can also change soil pH and destroy soil structure.

Boiling water is often touted as a sure-fire way of killing weeds. What you may not come across online is that any initial application will kill what appears above ground but will have minimal to no impact on the roots. Multiple applications will be needed to sufficiently weaken the root system and kill the weed.

You may be asking, “If household products are not necessarily the best route to take for weed management, what can be done?” The least toxic remedy is to dig them out by hand, roots and all, which can be somewhat of a daunting task if you come across a bunch. The best time may be when the soil is wet, after a nice rain. There are also various tools available online for purchase that may help make the task more manageable. Catching weeds early in their growth cycle is often the best remedy of all. As you periodically walk around your garden, you may see young, unwanted plants along the way, at the ready for plucking.

As a preventative measure, you can apply 2-3 layers of newspaper or a layer of cardboard when preparing a bed for planting, or around current plants, followed by 2-3 inches of mulch as a finishing layer. All can be effective weed deterrents.

Happy gardening!

Janetta Fox is a Lee County Master Gardener Volunteer and member of the Garden Club of Cape Coral. Visit us at gardenclubofcapecoral.com.