White oil is among the safest and most effective organic ways of controlling many sap sucking and leaf chewing pests in the garden. Gardeners have been using white oils for centuries, so they’ve been thoroughly tested. The best thing about white oil is that you can make it yourself!
White Oil Ingredients:
- Two cups of vegetable oil
- Half a cup of washing up liquid (dishwashing detergent)
Put the oil and washing up liquid into a jar or bottle. Put the lid on and give it a good shake and you’ve got concentrated white oil.
Label the concentrated mixture and store it in a cool, dry place. It’s a good idea to also label it with the dilution rate – two dessert spoons per litre of water.
Over time the two liquids may begin to separate again, just give them a good shake prior to use.
Dilute the concentrated white oil by adding two dessert spoons (about 20mL) to one litre of water. Mix well and add to a sprayer.
On hot days, it’s best to spray your plants in the cool of the morning. Cover both sides of the leaves and all of the bark. Don’t use the white oil on hairy or soft leaved plants like lettuce, because it will burn the leaves.
White oil will control scale, aphids, whitefly, mealy bug, and caterpillars. The white oil blocks the pests breathing pores and suffocates them. Because it works in this way, there is no chance of resistance to it.
White oil is indiscriminate in what it will kill. This means that spraying white oil on your plants may kill beneficial insects that are already working hard to control the pest outbreak for you. Make sure that you identify the garden pest correctly before spraying with white oil and try to limit the extent of the spray to reduce the impact on innocent bystanders.
An Alternative to Using White Oil
Good garden design with a focus on creating a healthy, diverse garden ecosystem can reduce the severity and impact of pests on your garden. Planting more flowering plants will attract beneficial insects to your garden to control pests for you. See our blog post on Pest and Predator Dynamics for more information on why you should hold off spraying those bugs!