Pest-Controlling Oils

Today's horticultural oils are effective, low in toxicity and can be applied just about any time of year.

Products made from various oils have been used in the garden for centuries. Ancient Romans used mineral oil to control plant pests, while the American colonists relied on whale oil.

Beginning in the 1930s, the oil of choice was a petroleum product known as dormant oil, so named because it was applied during the dormant season. It was used primarily to control scale insects and mites on dormant trees and shrubs.

Today new superior oils – also called highly refined oils or simply horticultural oils – have replaced dormant oil. They’re effective, low in toxicity and much lighter (that is, not as viscous). These oils can be applied just about any time, even during the growing season, and control not only pests but various diseases too, in particular fungal diseases.

The key to using horticultural oils during the growing season is to make sure the plants you’re spraying aren’t water stressed; if they are, some damage could occur. So simply water the plant well the day before you spray.

Neem oil is an excellent product for controlling pests and diseases. "It’s derived from the tropical neem tree," says Paul James, "and it works better than any other oil-based formulation I’ve ever used."

Within the category of herbicides, new products seem to pop up every year, says Paul, including one introduced in 2005 that is made from clove oil. "In my experience, these oils control weeds best when temperatures are warm, say in the 80s or 90s," he says.

horticultural oil (Concern/Necessary Organics) - Woodstream Corporation
clove oil - St. Gabriel Laboratories
neem oil - Safer Brand

Next Up

Deter Deer in the Garden

Learn how to keep deer from destroying your landscape and backyard garden.

How to Get Rid of Grubs

Grubs feed on the roots of your lawn and plants. Take control before these destructive pests get out of hand.

Humane Ways to Get Rid of Groundhogs and Keep Them Away

Got groundhogs? Discover effective, all-natural ways to keep these critters out of your yard and garden.

Does Potting Soil Go Bad?

Potting soil won’t last forever, in a container or in the bag.

How to Get Rid of Earwigs

Earwigs aren't pretty, and they can eat your plants and invade your home. Learn how to make earwigs bug off.

Lawn Seeding: How to Plant Grass Seed

To reinvigorate your existing lawn or plant a new one, follow these steps on how to grow grass in the spring and fall.

How to Keep Chipmunks Out of the Garden

Learn how to get rid of chipmunks in your garden and stop these critters from wrecking your yard.

13 Ways to Get Your Lawn Ready for Cool Weather

Learn how to prep your lawn for fall and winter to ensure green grass come spring.

Cicadas 2024: Everything You Need to Know

Two types of cicadas will emerge this year. This is a rare natural phenomenon that hasn’t happened since 1803! Learn about these fascinating creatures and find a few practical considerations for your home and garden.

How to Get Rid of Japanese Beetles

Get rid of Japanese beetles with a few of these easy strategies.

Go Shopping

Get product recommendations from HGTV editors, plus can’t-miss sales and deals.

On TV

Follow Us Everywhere

Join the party! Don't miss HGTV in your favorite social media feeds.