Found this online while looking for something else …
A Natural Spider Spray Formula for inside the house:
Dr Bronners Peppermint or Lavender Soap, or any other
natural soap.
1 ounce of Neem oil
You can also add 1 to 5 drops of any of these
Essential Plant Oils (depending on your preference) to
1 quart of water:
Catnip Oil, Citronella Oil, Lavender Oil, Cinnamon
Oil, Peppermint Oil, Citrus Oil, Tea Tree Oil, or
other essential oils.
Add 5 tablespoons of the soap per quart water. Add one
ounce of the Neem oil to the water which you have
added the soap and label it. Shake well and spray
inside house where spiders are seen.
Test for
strength. May be done as often as needed. This is not
a long term solution but will provide you immediate
help.
Oils may stain some fabrics or light colored
furnishings, test
first.