A bar of Fels-Naptha may be one of the simplest ways to keep pests from your garden. From repelling insects from your plants to deterring deer from munching on your flowers, it turns out this more than 125-year-old laundry soap can help naturally defend your home’s garden space against various infiltrators, including poison ivy — which was one of Fels-Naptha’s original uses.
Fels-Naptha, sold in bars, can be used as a detergent if combined with other ingredients, such as baking soda and borax, but it’s often grated to hand-wash clothes and to treat stains. This said, original versions of Fels-Naptha weren’t so safe for everyday use, as the soap contained naphtha, a flammable oil that posed a cancer risk, per the Paramus Fritz Behnke Historial Museum. However, today, Fels-Naptha is naphtha-free, and instead has several other ingredients, like terpene and tetrasodium etidronate, that help not only clean laundry but also fight garden pests.
Keep in mind that Fels-Naptha can cause eye irritation and, in some people, can be bothersome to the skin. Make sure to wash the soap off your skin after handling the laundry soap bar. Further, it’s not safe to consume Fels-Naptha, as it may cause diarrhea, abdominal pain, and/or nausea.
Using Fels-Naptha as an insect repellent and a deer deterrent
The application of Fels-Naptha as an insecticidal soap can be highly effective at repelling many of the small pests that eat away at the leaves of your plants. And the solution shouldn’t cause issues for your plants’ growth either. To create a defense for your plants, mix 1 tablespoon of Fels-Naptha laundry soap and 1 gallon of water. You’ll need to grate the bar soap into small pieces and then mix it into warm water to blend well. Pour this solution into a spray bottle and then, simply, apply liberally to the leaves, stems, and other areas of the plants at risk.
A bit of a simpler strategy works for repelling deer. Deer, who count on their sense of smell to find food sources, won’t come near this type of laundry soap when they smell it. However, you don’t actually have to spray it on anything. Instead, use a sharp knife to cut the bar soap into several chunks. Then, tie a string around the chunk and hang it from the areas where deer tend to come into your yard. This will help to ward them off.
If rain is in the forecast, take the Fels-Naptha soap deterrents down as rain will wash the soap away and it could get onto the surface of your lawn’s grass, creating a danger for pets who might munch on the grass. If you forget to take the soap down, don’t allow your pets to eat the affected grass, as it can cause illness and gastro issues to them, too.
Using Fels-Naptha to treat poison ivy (sumac and oak)
Another way to use Fels-Naptha is one that dates back to its 19th-century origin: as a remedy for poison ivy (sumac and oak). Poison ivy is one of the pests in your garden you don’t want to touch barehanded, but if that occurs or you get the resin on any other area of your skin, you could wash the area with Fels-Naptha, which will help to remove the sticky sap. Make sure to rinse well to remove all remnants (of the poison ivy and Fels-Naptha).
Don’t stop with just your skin, though. Wash any of the clothing you were wearing at the time of exposure in a laundry solution that contains Fels-Naptha. This will help to remove the oils from the poison-ivy plant that may be able to withstand typical laundry detergent. To use it for this need, simply combine the grated bar soap with your other laundry cleaners and wash your clothes as you normally would. It can be used in any water temperature and any type of washer cycle.
Be sure to grate the laundry soap bar to create more of a flake-like consistency. When using Fels-Naptha in your laundry, you’ll need about 1 tablespoon of the flakes per 1 gallon of water you use.
