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 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.

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.