Aphid infestation on hybrid tea rose
Anne W. Gideon, Bugwood.org
We think of soap as being used for cleaning purposes, but soap has also been used for centuries as an all-purpose pesticide against a number of different common garden pests, including aphids, spider mites, bugs of all sorts, Japanese Beetles, cockroaches, moles, deer and rabbits.
A study carried out in Turkey in 2000 which tested the effects of using natural pesticides on the yield and quality of cucumbers grown under greenhouse conditions showed that there were no significant differences between the yield and fruit properties when natural (soap-based) pesticides or conventional pesticides were used.
The recipes are simple, can be made at home and adapted for for specific uses.
Whenever applying a soap spray to your garden plants, it is a good idea to remove all dead leaves and plant matter from around the plant to ensure the mixture comes in direct contact with the bugs. Removing dead and decaying leaves and stems also removes places for them to hide.
Also keep in mind that there are also beneficial insects (bees, ladybugs and spiders, for example) and they can be adversely effected by these sprays as well. Use these soap-based natural insecticides responsibly!
Basic recipe for a simple insecticidal soap
- 2 -3 Tbs liquid soap or shaved hard soap
- 1 quart boiling water
Mix together. If using shaved soap, make sure the soap is completely dissolved. Transfer to a spray bottle and apply to plants liberally.Repeat daily until the infestation is gone.
NOTE: It’s important to use real soap, not a detergent. You can usually tell by looking at the ingredients.
To increase the strength
Add to the soap mixture:
- 1 small onion, finely chopped
- 1 Tbs cayenne pepper
Mix well, and let sit for an hour. Strain and pour into the spray bottle. Refrigerate any unused portions; it should keep for up to 2 weeks.
For Japanese Beetles
Make simple and inexpensive traps using open milk jugs, cans or buckets. Fill with:
- rotten fruit
- 1-2 Tbs Canola oil
- fill container 1/2 full with basic soap solution
Place traps around the garden.
Cockroaches
Soap mixtures can be effective against cockroaches because of the scent. They are apparently repelled by strong scents. Use the “Increased strength” recipe above. Spray around baseboard.
Also effective is catnip. Add 1 tsp catnip essential oil to the soap mixture and spray as above.
Deer and Rabbit repellent
Add 1-2 heads of garlic to the soap spray. Puree in a blender and then strain.
Another Deer Deterrent
Place bars of highly fragrant soap around the garden. Replace them when the scent diminishes.
Mole and Bird Deterrent
Mix castor oil with soapy water and sprinkle on the ground where the mole has been burrowing.
May you have good luck in applying these soap remedies to your garden!
