Many natural oils have the innate ability to adhere to leaves, stems, and other plant surfaces. This is one of the reasons organic gardeners turn to these natural oils to keep pests out of the garden. Another is that many of these natural oils have no adverse effect on the human body or the garden ecosystem; a fact which makes them invaluable!
On the other hand, there some very complex recipes out there for organic pesticides. Many of them require rare ingredients and complicated ratios, but offer no guarantee of success for all that preparation. The choice seems pretty clear.
The following five natural oils are the cream of the crop when it comes to organic pest control. And once you’ve tried them, they’ll become your new best friends in the home and garden. Each of these suggestions is designed to be mixed into some form of applicator, like a glass spray bottle, or an adjustable pressurized garden sprayer. With each oil, we’ll give you a brief background, best application method, and a short recipe where needed.
1. Cedar Oil
Best used on visible insects, and scale insects.
Cedar oil works by drying out the waxy outer shells of insects; killing most and driving off any survivors with its irritating effect on their bodies.
The oil should be applied directly to visible pests. (Be mindful that spraying cedar on plants will often send gnats into flight that were otherwise hidden.)
For people, the smell of cedar oil is fantastic. That alone makes the oil a great choice. Do be careful, however, because strong cedar oil can irritate human skin and eyes; and is hard to get off of your hands.
Be careful spraying cedar oil in wind. If it gets into eyes and nasal passages, this will also cause great irritation. (And you’ll be able to understand just how much bugs hate being coated in it!)
There are several companies that offer the product for retail customers, with simple instructions for mixing into a garden sprayer. Wondercide is one great example.
Most cedar oil instructions will tell you to apply the product on low-light (e.g., very cloudy) days, or in the early evening. You will want to spray enough so it just starts to drip off of the leaves, no less, no more. Like any horticultural oil, it will have a strong smell; so be aware it may linger in whatever container you put it in for some time, even after you remove the oil!
2. Eucalyptus Oil
Best used as a deterrent, especially for flies.
Eucalyptus oil will keep your outdoor activities fun and pest-free this summer (or any other time of year that insects get in the way of your outdoor adventures!)
Soak a few small cloth strips in a natural eucalyptus oil (synthetic will not work) and hang them around your patio. The smell is fantastic (for most people, anyway); but flies can’t stand the scent of eucalyptus. This is a great alternative to breathing in those nasty toxic fumes, like the ones given off by insect repellent candles.
Eucalyptus oil can also be used as a pesticide, not just a repellent. Many insects; including white-flies, mites, aphids and earwigs, die after coming into contact with the oil at high enough concentration.
To make a Eucalyptus Oil Pest Deterrent Spray:
In a glass spray bottle, mix together:
-1 tsp natural eucalyptus oil (not synthetic)
-1 tsp natural dish soap (to emulsify)
-2 cups of water
Double the amount of eucalyptus oil in the mixture to turn your deterrent into a pesticide.
You can also spray the double-eucalyptus recipe on your mulch and around the base of larger plants. This will also keep many insects and borers away from fruit trees and vines.
3. Neem Oil
General garden pesticide – on contact and through digestion.
Most everyone has at least heard of neem oil, which comes from native Indian evergreen tree, Azadirachta indica. Neem oil has been used for centuries, primarily to protect crops from insect pests; and for good reason. It is fantastic at deterring a broad array of vegetable predators!
For everything from slugs and snails to moths and caterpillars, neem is usually a safe bet for the organic gardener.
Anyone who has used it may have burned some plants along the way. Like any horticultural oil, timing is key. Neem should only be applied directly to plants in the evening or on a cloudy day.
Also note that this oil may need to be reapplied several times in order to fully eliminate stubborn pests. Keep an eye out for pest “symptoms” until the signs totally disappear.
When using neem, make sure you spray underneath the leaves, as bugs will often seek shelter there to wait for the oil to dissipate.
For mixing neem oil, you will need to add a few drops of natural dish soap (which is usually somewhere in the instructions which come with a bottle of the oil.)
And don’t worry. Neem is safe for spraying on edibles, too. It does have a strong odor, but the smell is easily removed through normal produce-washing methods.
You can pick up a bottle of 100% Organic Neem Oil here. Mix and apply according to instructions on the container.
4. Garlic Oil
Best used for large herbivores like rabbits and deer.
Garlic oil works well to deter both small and large pests. The oil itself does not have any highly effective killing properties. Garlic is simply distasteful for most large herbivores. (In fact, humans are one of the few species on the planet that likes to eat it!)
Use Garlic Oil to deter rabbits, squirrels, deer, fox, coyote, gophers, and a long list of insects.
There are other product options out there than simply garlic oil liquid. There are garlic oil spikes which you can “plant” around your garden. These are fairly effective against larger animals.
You can also use the fruits of your own garden to protect it, assuming you’re growing garlic bulbs.
Garlic should be ready to harvest in early spring. The key to making sure that bulbs are ripe lies in their shoots. If you look closely at the base of the garlic, there will be four recently dead shoots, or leaves there. When you see these, it means your garlic is at its most ripe and flavorful, and it’s ready to be harvested.
Harvest some garlic and let it dry. Or you can purchase a bulb or two from the grocery store.
How to make Homemade Garlic Oil Pest Repellent:
In a glass spray bottle, mix the following:
-10 cloves minced garlic
-2 tsp mineral oil
-2 1/2 cups water
-1 tsp natural dish soap (to emulsify)
5. Peppermint Oil
Most effective at deterring spiders and slugs.
Spiders are typically (or at least they should be…) welcome residents in your garden, as they are a crucial factor for natural pest control in small ecosystems like a garden.
Unfortunately, then second you reach for a tool only to find a bunch of creepy eyes surrounded by too many legs staring you down; it becomes all too easy to revoke that welcome for these beneficial arachnids.
Resist the urge to smash them. Reach for some peppermint oil, instead.
And remember, you don’t want to spray peppermint oil directly on spiders. (That’s just as bad as the boot!) Instead, spray the oil around “no-spider” zones before they move in.
Spiders smell through their feet; and because of that, they can’t stand walking on surfaces coated in a powerful minty oil like peppermint.
Spray areas where you store items like tools, clothing, gloves and planting trays – all of which are frequented by your hands. These same areas are a spider haven.
You may also want to spray areas where webs will be extremely unsightly; such as your display of quaint garden trinkets. Any areas treated with peppermint oil will repel spiders as soon as the first of their eight tiny feet touches the minty surface. They will be disgusted, turn around, and catch flies in a more appropriate area of your home and garden.
How to make Peppermint Anti-spider Spray:
To dilute your peppermint oil, you may want to choose a base in which the oil will easily disperse (e.g., vodka or vinegar). If you want to use water, you will need to add natural dish soap as an emulsifier.
Into a glass spray bottle; mix:
-10 oz of your base liquid
-50 drops of natural peppermint oil (not synthetic)
-liquid dish soap (as needed)
If you use water, remember to shake before each use.