Cookies help us to offer you a personalised browsing experience and to measure our audience. You can configure them at any time and consult our privacy policy.

Read our policy

Care for garden plants with essential oils
Choosing planting

Care for garden plants with essential oils

How to use them in the garden and vegetable patch?

Contents

Modified the Sunday, 10 August 2025  by Alexandra 3 min.

Essential oils are well known for their medicinal properties, helping to improve human health and well-being, but they also have uses in the garden and vegetable patch for treating plants! Their use is ideal to avoid the use of synthetic pesticidal products. Alongside other natural gardening techniques, such as using manures, decoctions, infusions, and companion plants and preventative techniques, essential oils will help you tackle problems you may encounter in the garden!

Some are effective at repelling pest insects, others are useful for combating diseases caused by fungi and bacteria. Here are all our tips for treating your plants with essential oils, fighting diseases and parasitic pests naturally, without using chemical products. Discover how and when to use them!

Difficulty

.

.

.

Basic principles and precautions to take

Essential oils are concentrated, volatile extracts obtained by distillation. They contain highly effective active compounds, often with antifungal and antibacterial properties, and sometimes insecticidal.

Essential oils are very rich in active compounds, so use sparingly and with caution, not excessively. Initially, favour gentler techniques: decoctions, infusions, manures, black soap… Essential oils are used curatively rather than preventively and should serve as an adjunct treatment, to be used only if other gentle techniques fail. Also avoid overdosing to increase effectiveness: as essential oils are very concentrated extracts, at too high doses they can become toxic for plants.

Check that weather conditions are suitable to treat in dry, wind-free conditions. Before beginning to use essential oils, protect your skin and eyes, as they can be harsh and irritating (notably to mucous membranes as well as to other parts of the body). Likewise, after use, wash your hands thoroughly.

Finally, to store and preserve essential oils between uses, it is important to keep them protected from light and heat.

Essential oils for the garden

Essential oils

How to use essential oils in the garden?

Essential oils do not mix directly with water: a surfactant is required — mix them with a little black soap or washing-up liquid, for example.

To prepare an essential oil-based garden treatment, we therefore recommend:

  • start by diluting 20 to 25 drops of essential oil in a spoonful of black soap, then in a glass of water,
  • prepare a clay slurry, to help disperse the product and ensure better adhesion on plants. To do this, mix some very fine clay with a litre of water,
  • you can then add the glass of water containing the black soap and essential oil to it,
  • mix well and spray onto your plants.

Which essential oils for which treatment?

Against parasitic insects and pests:

To control pests that weaken plants by drawing sap or eating leaves, garlic and clove essential oils are of interest because they have a wide spectrum of action. Peppermint is a very good insecticidal agent against aphids in particular, and against caterpillars. It is also effective against many other insects.

You can also create a general, broad-spectrum insecticidal spray by mixing several essential oils, for example peppermint, clove and rosemary.

Here is a list of main pests that can be kept at bay with essential oils:

  • Aphids: peppermint, common sage, garlic, cedar, spike lavender…
  • Whiteflies: rose-scented geranium, lavender
  • Scale insects: cinnamon, rose-scented geranium, bitter orange petitgrain
  • Flea beetles: peppermint
  • Defoliating caterpillars: peppermint, garlic
  • Red spider mites: rosemary
  • Codling moth: juniper
  • Carrot fly: rosemary

Against aphids, you can use peppermint or common sage essential oil

Against diseases:

Against fungal diseases, caused by a fungus, tea tree essential oil proves quite useful: it has a wide spectrum and is effective notably against powdery mildew, downy mildew, anthracnose… Garlic essential oil also has good antifungal properties.

Finally, sandalwood essential oil has the advantage of strengthening plants, thereby making them more resistant to disease.

Here is a list of main plant diseases that can be treated with essential oils:

  • Powdery mildew: garlic, wild thyme, tea tree
  • Downy mildew: oregano, tea tree, clove, rosemary
  • Rust: tansy
  • Sooty mould: oregano, cinnamon
  • Canker: wild thyme
  • Brown rot: oregano, savory
  • Anthracnose: tea tree
  • Peach leaf curl: savory
treat powdery mildew with essential oils

For powdery mildew, spray tea tree or wild thyme essential oil

Against snails and slugs:

To repel gastropods and prevent them nibbling foliage, we recommend spraying cedar essential oil. Garlic, hyssop and pine essential oils also seem effective.

To attract pollinators:

Although essential oils can be used against unwanted insects, some are ideal for attracting pollinating insects to the garden! Try in particular essential oils of lavender, neroli and hyssop.

To go further:

 

Comments

Essential Oil Treatment in the Garden In the realm of gardening, the use of essential oils is gaining traction not only for their aromatic properties but also for their roles in plant care and pest control. Here, we explore how essential oils can be integrated into your gardening practices to enhance the health and vigour of your plants. ### Benefits of Essential Oils in Gardening Essential oils, concentrated extracts from plants, are renowned for their strong scents and therapeutic properties. In the garden, these oils can serve multiple purposes: - **Pest Repellent:** Oils such as peppermint, lavender, and eucalyptus can deter pests like aphids, beetles, and mites. - **Fungal Control:** Tea tree and neem oils are effective against fungal infections that can afflict plants. - **Plant Growth Stimulant:** Some oils, including lavender and rosemary, can promote healthier and more robust plant growth. ### How to Use Essential Oils in Your Garden To harness the benefits of essential oils in your garden, follow these guidelines: 1. **Dilution is Key:** Essential oils are potent and should be diluted before use. A common ratio is a few drops of essential oil to a litre of water. Always mix thoroughly. 2. **Application Methods:** You can apply the diluted oil mixture using a spray bottle or add it to your watering can. Spraying is particularly effective for pest and fungal control. 3. **Regular Application:** For best results, apply your essential oil treatments regularly. Once a week is a good starting point, but you may adjust the frequency depending on the specific needs of your garden and the local climate conditions. 4. **Targeted Use:** Apply oils directly to the areas affected by pests or disease, or use them as a preventive measure on healthy plants to maintain their vigour. ### Precautions While essential oils are natural, they are also powerful. Here are some precautions to keep in mind: - **Test on a Small Area:** Before widespread application, test the oil on a small part of the plant to ensure it does not cause damage. - **Avoid Overuse:** Excessive use of oils can harm plants. Stick to recommended dilutions and application frequencies. - **Consider Plant Sensitivity:** Some plants may be more sensitive to oils than others. Research or consult an expert if you are unsure about the effects on specific plant species. Integrating essential oils into your gardening routine can be a natural and effective way to enhance plant health and protect against pests. With careful use, these potent botanical extracts can be a gardener's ally in cultivating a thriving garden.