A good repellent should not only be able to ward off spiders, but also keep a home's inhabitants safe. Many repellents contain chemicals such as the poisonous substance called diethyl-meta-toluamide (DEET). Human exposure to DEET can cause mild skin irritation or even death. Natural repellents are alternatives to chemical repellents. Natural repellents for spiders can be made using certain herbs.
Tobacco is sometimes used to repel spiders. This natural remedy involves soaking chewing tobacco in boiling water. After the tobacco cools, strain and keep the tobacco-infused liquid. Combine two parts of this liquid with one part liquid soap and spray the mixture on windows, vents and cobwebs.
Citronella oil, lavender oil, cinnamon oil, peppermint oil, citrus oil and tea tree oil are inexpensive oils that will kill spiders -- as well as other insects -- on contact. Put 1.1 litres (1 quart) of water in a spray bottle. Add 30 ml of neem oil and four drops of the essential oil of your liking. Spray the repellent around doors, windows and vents to repel spiders.
Chestnuts and eucalyptus
Some people believe that chestnuts can repel spiders, although no scientific evidence supports the claim. Scatter whole chestnuts and sections of osage oranges -- commonly known as hedge apples -- around areas where spiders have been spotted as a possible deterrent. Eucalyptus is another herb believed to repel spiders. Place eucalyptus leaves on shelves and in closets and drawers.
Other natural repellents
Vinegar is yet another natural alternative to chemical repellents. Vinegar's scent repels spiders, which makes it an effective indoor deterrent. Mix one part vanilla extract with three parts white distilled vinegar in a spray bottle. Spray the mixture into cabinets and dark corners of your closets. Also, use the mixture on window and door sills to prevent spiders from coming in through small cracks or openings.