How much salt to how much water should I mix for a nasal solution?

Nasal solution. Add ½ to 1 teaspoon of unionized salt to an 8-oz glass of lukewarm water (distilled or boiled tap water). The concentration of salt water solution should match or exceed the concentration of the body cells and blood (isotonic or hypertonic). May add a pinch of baking soda to prevent burning.
NASAL SALINE. Mix one-half teaspoon uniondized salt in an 8-ounce glass of water (described above).  uniodized salt is used because iodized salt may be irritating when used over a long period of time. Add a pinch of baking soda. A pinch is a small amount you can pick up between two fingers. If you are congested, use the entire 8 ounces of saltwater during the nasal wash; http://www.Nationaljewish.Org/healthinf.
Don't use home made. While it is popular to make up a home mix of nasal wash/saline there are significant drawbacks. If you get it a bit too dilute or too concentrated the material will not work appropriately. Boggy swollen overhydrated nasal membranes are common. Local dollar stores carry 2oz bottles for a $1 & unless you can make it well the otc stuff is worth the investment.
Easy home remedy. This is an easy home remedy for a dry nose. I recommend starting with about 8 oz of warm water in a clean container. Add about 1/4 teaspoon of salt to the water and stir in about 1/4 teaspoon of baking soda. Stir the mixture well making sure the salt and baking soda have dissolved completely. Tip your head back and insert the saline into one nostril at a time using a bulb syringe.