dish soap to prevent mosquitoes in rain barrels
News, notes and thoughts from Blue Water Baltimore. How to Keep Your Rain Barrels Free of Mosquitoes. Liquid Dish Soap. Use one tablespoon once a week or after each storm. Mosquito Dunks. Use one 1 dunk once a month or as needed. Vegetable Oil. Use Â¼ cup once a week or after each storm. by Vincent Vizachero. Your rain barrel is designed to keep mosquitoes out, but there is no guarantee that these pesky creatures wonât find a crack in the system.
1 To prevent mosquitoes from laying eggs, add a tablespoon of dish soap or 1â4 cup of vegetable oil to form a film on the top of the water.  2 A diverter should be part of your rain barrel so overflow can be redirected away from the foundation of your house. To prevent mosquitoes from laying eggs, add a tablespoon of dish soap or 1â4 cup of vegetable oil to form a film on the top of the water.  2 A diverter should be part of your rain barrel so overflow can be redirected away from the foundation of your house.