DIY White Oil: A Horticultural Oil for Garden Pests

by Corinne Mossati

White oil is a home-made organic pesticide used to control a variety garden pests and can easily be made at home using common household ingredients. Here’s how.

White Oil

White Oil – Photo © The Gourmantic Garden

Garden pests are a fact of life but there’s no need to go out and buy pesticides with chemicals that end up in your edible garden and harm beneficial insects. White oil is a home-made organic pesticide used to control a variety garden pests. Also known as horticultural oil, the liquid is not a poison but acts on pests by blocking their breathing pores which causes them to suffocate and die.

White oil is effective in the control of sucking and chewing insects such as aphids, scale insects, mealybug, mites, citrus leaf miner, whitefly and some caterpillars. It also kills ants instantly which is helpful if you have a large infestation. It gets its name form its colour – the liquid turns milky when shaken.

You can buy it ready made but most commercial products have some type of petroleum oil as the active ingredient whereas a home-made insecticide has plant-based oils. It’s also safe to use on edibles.

White oil is very simple to make at home from common household ingredients, detergent and vegetable oil.

DIY White Oil Recipe

  • 1 cup dish-washing detergent, preferably earth-friendly
  • 2 cups light vegetable oil such as sunflower oil or canola oil

To make the white oil, you first make the concentrate. Pour the detergent and the oil into a glass jar, close the lid and shake until it turns milky in colour. Label with the name and dilution rate (1T concentrate: 1L water) and store it out of sunlight until ready to use.

To use, add one tablespoon of the concentrate to one litre of water. Fill a spray bottle, give it a good shake and spray the affected plant.

Always spray both sides of the leaves as well as the stem of the affected plants. Do not spray on flower blooms and don’t apply the white oil in the middle of the day or when the temperature is greater than 30oC to avoid leaf burn. Depending on the type of infestation, you may need a few applications.

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