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!
Parsley Seed Essential Oil
Parsley Seed Essential Oil (Petroselinum crispum), native to the Mediterranean region, is a thin and clear to pale yellow oil that is steam distilled. It has a fresh, herbaceous, slightly spicy scent, with a touch of sweetness.
In the Garden
Parsley seed essential oil acts as a powerful, natural bioinsecticide and bioherbicide.
Its complex chemical profile is rich in apiol, myristicin, and other monoterpenoids, making it highly effective for targeted pest control while remaining a greener alternative to synthetic chemicals.
Its primary applications and biological impacts include:
Fumigant & Insecticidal Toxicity:
The oil demonstrates strong fumigant and contact toxicity, effectively knocking down greenhouse pests like the Whitefly and Stored-grain Beetles.
Greenhouse Whiteflies
Researchers tested the fumigant toxicity of Parsley seed essential oil in the control of pests in small greenhouses. They focused on the greenhouse or glasshouse Whitefly (Trialeurodes vaporariorum), a major global agricultural pest that affects over 250 plant varieties across 84 families. It damages crops by extracting phloem sap and secreting honeydew, which fuels the growth of photosynthetic-blocking sooty mould.
The results of this experiment show that parsley seed essential oil has a good control effect on whitefly adults, and that and this natural oil is safe for the environment and other mammals.
Mosquito & Vector Control:
Parsely seed essential oil is a potential bioinsecticide, and has proven anti-mosquito activity against both pyrethroid susceptible and resistant strains of Ae. Aegypti. Studies show it exhibits significant larvicidal effects, causing high mortality in malaria-carrying mosquito larvae (Anopheles coluzzii.
The essential oil can inhibit detoxifying enzymes in insects, which boosts the toxicity of traditional insecticides like pyrethroids and organophosphates. This makes it highly useful in integrated pest management to fight resistant mosquito populations.
Stored-product Insect Pests
Studies done of the toxicity of the essential oils isolated from parsley seed against three major stored-product insect pests proved its effectiveness.
Cowpea Weevil (Callosobruchus maculates)
The cowpea weevil is a highly destructive, cosmopolitan agricultural pest that primarily infests and damages stored legumes and pulses, such as cowpeas, lentils, and chickpeas
Mediterranean Flour Moth (Ephestia kuehniella)
The Mediterranean flour moth or mill moth is a cosmopolitan pest commonly found in cereal grains, flour mills, and bakeries. In South Africa, this moth is officially classified as an alien species. It is widely distributed across the country and is well-known both as an economic pest in food storage and as a key species utilized in biological control programs.
Indian Meal Moth (Plodia interpunctella)
In South Africa, the Indian meal moth is frequently encountered in pantries, kitchens, and food storage facilities. They feed on a wide variety of dried food products, including grains, cereals, and flours, dried fruits, shelled nuts, pet food and bird seed.
Bioherbicide Potential
Parsley seed oil demonstrates high phytotoxic activity and can inhibit seed germination and root growth, making it a promising agent for natural weed control.
Post-Harvest Protection
Fumigation
The essential oil can be introduced to sealed storage containers to deter pests and affect adult development without impacting the germination rate of legumes or cereal.
Protection
Add a few drops of pure oil to porous clay pucks or sachets and place them inside sealed storage containers. The released fumes safely repel beetles without diminishing seed viability or germination rates.
Impregnating storage bags with parsley essential oil has been studied as a tool to manage and repel crop-destroying insects without using harmful chemical residues.
The Cotton Wool Method listed below is also effective.
Garden Spray
Mix 10-20 drops of the essential oil in 1 Litre of water with an emulsifier. Shake well, and regularly while spraying down the foliage of plants.
In the Home
Parsley Seed Essential Oil is a thin and clear to pale yellow oil that is steam distilled. It has a fresh, herbaceous, slightly spicy scent, with a touch of sweetness.
It supports the body’s natural detoxification process and promotes fluid balance with gentle diuretic action. Its antimicrobial and antioxidant properties help defend against environmental stressors, while its digestive support can ease occasional discomfort. This oil is often used in aromatherapy and skincare formulations to refresh and invigorate.
Diffusing essential oils will deter many common indoor pests
- 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.
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.
