10 drops Citronella
10 drops Thyme
1/2 drops Distilled Water
3 drops 160 proof or higher alcohol
Add the essential oils and either the alcohol or the Solubol to a 4oz dark coloured glass spray bottle and shake well. This will dissolve the oils and prevent them from separating from the water.
Fill the bottle with distilled water leaving a bit of a gap at the top (use a bit less than half a cup of water). Screw the top on, shake well and spray. Shake the bottle before each use.
The recipe is based on this study, which tested 11 different essential oils and found that the combination of citronella and thyme was the most effective against ticks.