Description
Essential Oils for the Home & Garden
If you are trying to limit your exposure to toxic and synthetic chemicals in your garden and home essential oils can be valuable tools. They are well-known for their wellness virtues for humans, and can also be precious allies to protect your plants naturally and ecologically.
These oils have been used for thousands of years for their medicinal and cosmetic benefits, and their power lies in the hundreds of chemical constituents they contain. Whether you are trying to chase away garden pests from your vegetable or flower garden, protect your plants against diseases, or simply to improve their overall health, we can use these natural defences to our advantage in both our home and garden, using products you can store in your medicine chest. How cool is that!
Marjoram Essential Oil
Steam distilled from the leaves and flowering tops of Origanum majorana, native to the Mediterranean region, this thin, clear to pale yellow oil offers a warm, comforting scent with herbaceous and subtly sweet undertones.
In the Garden
As a pesticide
Marjoram Essential Oil serves as a potent natural insecticide and repellent, and is a highly effective, natural alternative to synthetic pesticides. The essential oil is prized for its key components like terpinen-4-ol and α-terpinene, which safely repel pests, deter fungal growth, and clears up mould.
Marjoram essential oil acts through direct toxicity and fumigation. Its active secondary metabolites such as terpinen-4-ol and linalool interact strongly with insect detoxification enzymes and nerve targets, making it a viable alternative for organic pest management.
The oil is great for deterring common soft-bodied insects like Aphids and Mites without harming beneficial pollinators.
Black Cutworm (Agrotis ipsilon)
The essential oil is highly effective against crop pests like the black cutworm, which is one of several cutworm species found throughout South Africa, and are notorious pests of maize, wheat, and vegetable crops. In South Africa, cutworm populations generally peak following early summer rains and warm weather, particularly in fields containing weeds or crop residues.
In the space they’ve borrowed into, they’ll create a small pupal chamber and begin developing into adult moths. Cutworms pupate for a few weeks before emerging as their fully-formed adult moth counterparts in August and early September.
While the black cutworm is widespread, the most prominent and economically significant species in the region is actually the Common Cutworm (Agrotis segetum), and farmers in South Africa typically manage these larvae by keeping fields bare of weeds for about 35 days before planting to starve the emerging caterpillars, and by applying registered insecticides when necessary.
To apply an essential oil, spray thoroughly around the base of the plants and directly onto the soil where black cutworms hide during the day. Apply during late afternoon or early evening, as cutworms feed at night and UV light degrades essential oils quickly.
German Cockroaches (Blattella germanica)
Marjoram essential oil has proven effective against German cockroaches, a troublesome species found in South Africa. They thrive in warm, humid indoor environments like kitchens and bathrooms. They are small, growing to only about 10 to 15mm in length, and a light brown or tan with two distinctive, almost parallel dark stripes on their backs behind the head.
These cockroaches are prolific breeders, and a single female can produce hundreds of offspring in a short time, making infestations particularly challenging to eliminate. German cockroaches are known vectors for spreading diseases such as gastroenteritis and dysentery, and their shed skins can trigger allergies or asthma in children.
Antifungal & Foliage Cleaner
Marjoram essential oil boasts natural antifungal properties to help prevent common blights and fungal issues like powdery mildew on plants.
Garden Spray
Mix 15-20 drops of essential oil with 1 teaspoon if liquid soap as an emulsifier and add to 1 Litre of water. Agitate and spray.
Indoors and around patios etc. cotton wool balls soaked in the essential oil and tucked into vulnerable areas will deter many pests.
In the Home
The thin, clear to pale yellow oil is herbaceous and slightly spicy with a soft sweetness. Its middle note perfume blends well with lavender, cedarwood, bergamot, and clary sage.
Traditionally valued for its calming and pain-relieving qualities, this oil is a favourite in massage, bedtime formula , respiratory and digestive blends
If diffused it will repel many of the pests mentioned above.
- Add a few drops to a diffuser to create a peaceful, meditative atmosphere.
- Dilute with carrier oil for use in massages or skincare applications.
- Combine with Epsom salts and other relaxing oils for a deeply calming bath soak.
How to Use Essential Oils for Pest Control
When it comes to organic gardening, prevention is better than cure, and spraying crops regularly with essential oils to prevent insect infestation and disease is the most effective method. This will not only chase pests away, but also make your garden smell great!
Always use pure essential oils, and because they are so potent, always dilute them first.
How to dilute essential oils
One of the drawbacks of using essential oils in the garden is that the levels of terpenes and other constituents can vary greatly depending on the region where the plants are grown, genetics, climate and other seasonal factors. Therefore, maintaining consistency in the chemical profile of the oils is hard.
For example, Rosemary oil extracted from plants growing in two different regions of Italy will contain varying levels of α-pinene, ranging from 11% to 36%. Another study showed that essential oils extracted from different chemotypes of garden thyme did not have the same toxicity against the bean weevil.
This is the reason why, if you look for exact recipes for the oil you wish to use in the garden, you will find many different quantities of oil versus water used.
Another factor to take into account is the actual number of drops in a milliliter can vary greatly depending on the thickness of the liquid: Thicker liquids like essential oils produce larger drops, meaning it takes fewer drops to make 1mL. Different dropper bottles or droppers also have varying nozzle sizes, which changes the volume of a single drop.
In standard pharmaceutical measurements, 1 mL is equal to approximately 20 drops (meaning 1 drop is about 0.05 mL). Therefore, 10 drops are typically equal to about 0.5 mL.
This is why physicians do not rely on counting drops, as this can lead to incorrect dosing. Instead they use an oral syringe, a graduated measuring cup, or the specific dropper provided with the medicine.
Because the actual number of drops in a millilitre can vary greatly depending on the thickness of the liquid and varying nozzle sizes, which changes the volume of a single drop, I recommend starting with the lowest recommended dosage. You can always increase it later.
CAUTION:
Because the actual number of drops in a millilitre can vary greatly depending on the thickness of the liquid and varying nozzle sizes, which changes the volume of a single drop, I recommend starting with the lowest recommended dosage. You can always increase it later.
Preventative spraying
A general guideline when mixing sprays to deter insects, and for anti-fungus protection is to mix 4–8 drops of Essential Oil in 1 Litre of water with an emulsifier.
Garden Sprays
At certain times of the year various pests and diseases will be more prevalent, so for stronger protection dosages can be increased.
Generally you will find recommended dosages are between 10-20 drops per Litre of water.
Always Test Sprays First
Unless you apply very high doses of essential oils, they are perfectly safe to use in the garden. However, because the strengths of essential oils vary, to ensure they do not cause leaf burn, it’s important to always test your spray on a small, isolated area of the plant first. Wait at least 24 hours to check for damage before applying it everywhere.
A good method of remembering which leaves you tested your spray on is to tie string or ribbon onto the stems that have been sprayed.
Take Notes
Taking note of which plants were tested and the dosages used, will soon give you a good indication of the strengths your plants need for protection.
Mixing your spray
The Emulsifier:
Soap is essential as an emulsifier as essential oils do not mix with water and will float to the top, potentially burning your plants. A gentle liquid dish soap, pure liquid Castile or Black soap can be used.
Approximately one teaspoon of liquid soap emulsifier is used in one litre of water. Witch hazel, Vodka, or apple cider vinegar also emulsifies oil and water.
The Method:
In a small glass container, mix your essential oils with your emulsifier, then add some of the water and stir well. Warming the water helps with emulsification. Add the oil mix to the spray bottle with the rest of the warm water. Agitate well and also regularly whilst spraying.
Applying your Oils
Spraying in the middle of a hot, sunny day can cause leaf burn, so always apply the mixture in the cool of early morning or late afternoon. Remember to agitate the spray bottle well before use, and regularly while spraying. Ensure that you spray underneath the leaves where insects commonly hide.
During the cooler times of the day beneficial daytime pollinators are not that active. Never spray plants if you can see beneficial pollinators like bees around the plants. Even organic sprays can be abused in the garden, so as they say “everything in moderation”.
NOTE: The strength of the oils will evaporate, so reapply to plants after rain, every 2 weeks, or as needed.
Cotton Ball Method
To target specific insects in large numbers, like ant hills or rodent burrows, take some cotton balls and add a few drops of essential oils to them. Place the cotton ball right onto the ant hill, burrow or other insect grouping. This will cause them to relocate immediately. If that doesn’t work immediately you should repeat the process using a stronger solution.
You can also rub the oils onto any hard surfaces to create a long-lasting barrier.
Hanging Strips to Deter Pests
Add essential oils to a bowl of warm water and soak strips of pretty material or ribbon in the water before hanging onto the branches of fruit trees, or near edible gardens and ornamental shrubs.
Is there a waiting period before harvesting?
You should not eat vegetables and fruits immediately after spraying them with essential oils. These oils are highly concentrated and consuming them without a waiting period or proper cleaning can cause digestive upset, inflammation, or irritation of the mouth and oesophagus.
Essential oils degrade in sunlight and waiting 24 hours should be sufficient. Ensure that you always wash your food well and all will be fine.
Storing Essential Oil Mixes
Try to mix up only sufficient spray to use in a day, or within 24 hours of mixing. Once exposed to water and oxygen, oil-based garden sprays begin to separate, degrade, and lose their effectiveness.
If you do have any left-over, store it in a glass bottle in a cool, dark place, not in your plastic spray bottle, as essential oils break down quicker in plastic. Agitate well before using again.
