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Tea Tree Oil Fungicide for Plants

Root rot, leaf spots or blights and mildews affect all gardens to some degree. Using chemical fungicides can effectively eliminate these fungal infections, but they also can harm nearby plants and some are dangerous to use around children and pets. Tea tree oil is a naturally occurring fungicide which, when diluted, offers fungicidal control for your plants.

Tea Tree Oil Information

Tea tree oil is the essential oil of the Melaleuca alternifolia tree and long has been used as an antiseptic and insect repellent. It has antimicrobial activity that makes it effective for use combatting fungi as well. There are more than 300 varieties of the Melaleuca tree, but only the melaleuca alternafolia’s oils contain these antiseptic and fungicidal properties. It is natural and safe for use inside your home or outside in your garden. According to the Mayo Clinic, tea tree oil's antimicrobial properties may be largely due to its main component, terpinen-4-ol.

Homemade Tea Tree Oil Fungicide

There are many natural plant fungicide recipes that use a variety of essential oils such as neem. To make tea tree oil fungicide, mix 2 tbsp. tea tree oil and 4 tbsp. baking soda into 1 gallon of water. Baking soda helps to control mildews while the tea tree oil kills fungus and repels potentially harmful insects. Some recipes call for dish soap; if you use an organic soap there is no problem adding some, but many soaps contain agents that can harm your plants.


Spray tea tree fungicides on infected plants every three days to once each week to control mildews and other fungal infections. Spray in the morning, before the sun is high. Midday sunlight can cause oil-treated leaves to burn. Use the solution sparingly and avoid soaking the foliage with spray. Target only the problem areas. Do not use fungicides on new plants or transplanted seedlings. If leaves begin to wilt, reduce the amount of soap in your spray or dilute it with water. During periods of warm, dry weather, do not apply fungicides, even if they are made from natural products, more than once each week.

Preventing Fungal Infections

Prevent reinfection or spreading the fungus to other plants by removing all infected material from your garden. Clean away fallen plant debris and prune diseased areas from your plants. Place these in a garbage bag or burn them. Do not compost diseased plant material. Some fungi spores can remain viable in the compost and will infect plants when applied to the soil. Water your plants regularly, but avoid overwatering. Most fungi prefer wet environments. Rich soil with enough nutrients to feed all of your plants also ensures a more vigorous garden. Healthy plants are better able to ward off fungal spores and survive infection.

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