While essential oils are commonly used to treat diseases, they are just as beneficial in the garden. Their diverse properties allow them to prevent and treat certain ailments that affect plants. They are also effective in the fight against insects. Zoom on the virtues and the recipes of use of these extracts.
Essential oils to treat plant diseases
Essential oils can fight certain cryptogamic and bacterial diseases that affect plants. This is due to the active components they contain. Flavonoids act in particular on fungi by slowing down their development. The acids, for their part, stimulate the immunity of the plants and reinforce their defense against the diseases. These exceptional essences are thus effective, not only to prevent the attacks of the parasites, but also to treat the already present infections.
The essential oil of wild oregano is used against mildew, moniliosis, scab, or fumagina. It is sometimes associated with other essential oils that have the same properties such as mountain savory oil that also acts on mildew and peach blister.
Mildew can also be treated with lemon, sweet orange, clove, sage, or tea tree essential oils.
Garlic essential oil is most popular for treating powdery mildew.
Tansy essential oil is mainly used against rust.
In order to optimize the fungicidal action of essential oils, it is possible to combine several extracts, provided that their properties complement each other.
Essential oils to repel pests and insects
Some essential oils are used in the garden as repellents. Their active components allow to prevent the invasion of pests and insects, thus avoiding their proliferation in the vegetable garden. Esters are particularly effective in scaring away pests. Parasites such as mites and nematodes do not tolerate lactones either, which prevent their development on plants.
Garlic and clove essential oils are the most requested as repellents. They are very effective in repelling insects and parasites, both in a small garden and in arboriculture or market gardening of larger scale. The actions of these essences are broad, unlike some essential oils that target specific pests or insects.
The essential oil of juniper is especially used to scare away the codling moth. Its action is mainly exploited in orchards.
Essential oils to eradicate insects
In case of insect invasion, essential oils can also come to the rescue of the garden. Some essences have high insecticidal properties. To know:
Garlic essential oil which, in addition to being a generalist insect repellent, can also eliminate ants, aphids, as well as defoliating caterpillars.
The essential oil of petit grain bigarade used against aphids and mealy bugs.
The essential oil of rose geranium to eradicate effectively the Colorado beetle, whitefly, but also aphids, caterpillars and mealy bugs.
The essential oil of grapefruit acts on the Colorado beetle.
The essential oil of peppermint which is used especially to eliminate aphids and defoliating caterpillars.
Essential oils to help plants
In order to optimize the growth of plants, essential oils can also play the role of companion plants. Instead of combining crops in the garden, simply spray essential oils on the plants to help them grow better. Some essences fight at the same time insects and prevent diseases which can harm the good development of plants. Be careful, however, to choose the right extracts, because not all the components of essential oils are suitable for all plants.
Thyme essential oil is ideal for cabbage varieties such as broccoli, cauliflower and cabbage.
Basil essential oil is a good companion for potatoes, asparagus, tomatoes, but also broccoli.
The essential oil of mountain savory can boost the growth of corn, beans, as well as onions.
Sage essential oil is used for the good development of cucumbers, carrots, cabbage, as well as potatoes.
And for roses in particular, garlic essential oil is effective in stimulating their fragrance and vigor.
The basic recipe for using essential oils in the garden
Essential oils are not used in a raw way but diluted, to be sprayed afterwards. There is a basic recipe that must be followed for any use in the garden. Indeed, instead of being beneficial, an overdose of oil extract can on the contrary harm the good growth of plants.
Thus, as a general rule, 20 drops of essential oil correspond to 1 liter of water. Ideally, prefer rainwater previously filtered and at room temperature to respect the natural environment of plants. However, as essential oils are not soluble in water, another ingredient is required: a surfactant.
Here are the steps to follow for the preparation of the recipe:
Start by making up the base. Combine the 20 drops of essential oils with a dab of black soap or a few drops of dishwashing liquid. Mix the whole in a glass of water or in a little vegetable oil. Emulsify well and set aside.
Prepare clay milk by pouring a teaspoon of green or white clay into 1 liter of water. Mix well. The clay milk is essential to make the essential oil treatment last. Indeed, these plant essences are very volatile and are easily removed after spraying. The clay milk improves their adherence and thus makes it possible to lengthen their action.
Mix everything together and spray the product on the foliage of the plants concerned. The operation is generally done twice a week, spaced out one week. Be sure to check the weather before spraying. It is important to avoid rainy days.
Recipes to get rid of pests in the garden
Here are examples of recipes to prepare with essential oil to fight against insects:
Pour 4 drops of washing-up liquid in 20 drops of peppermint essential oil. Mix and put the whole in a glass of water. Add 1 liter of clay milk, mix and spray.
Mix 4 drops of peppermint essential oil with 10 drops of table oil. Dilute in 100 ml of water. Emulsify well and spray. This preparation is very effective on roses.
Pour 5 ml of essential oil of wild oregano in 10 drops of washing-up liquid. Mix well and add 5 ml of rapeseed oil. Emulsify the whole and dilute in 3 liters of water. Shake well, then add another 4.5 liters of rainwater. Mix and use directly on infected plants.
Some precautions for use
Essential oils contain very powerful active ingredients. Some essences can attack the skin and the respiratory tract. Also, it is necessary to protect oneself well during their pulverization. Ideally, wear a long-sleeved shirt, a mask, a scarf, as well as glasses during the operation. In case of bad handling, essential oils can also be toxic and present risks of allergies. Wearing gloves is therefore mandatory for a safe use. After handling the products, do not forget to wash your hands.