How Often Should You Apply Fungicide Spray?

Initial Treatment

• Don't wait to apply fungicides. Many treatments are applied to plants even before fungal infection symptoms appear. Fungicide acts as a barrier against fungus, protecting the cell structure and inner workings of plants from the disease-causing fungi. Rain and wind decrease the effectiveness of fungicide, so it must be reapplied regularly to continue protecting plants. Even sunlight naturally wears away fungicide over time, and new growth does not have the fungicide protection until it is reapplied to the plant.

Standard Intervals

• Most fungicides are applied to plants every seven to 14 days, but this is only if weather conditions remain normal. If you notice plants growing rapidly, or weather conditions are extreme, fungicide may need to be reapplied even sooner. Excess wind and rain wear away fungicide quicker. By the same token, drought conditions could lengthen the necessary interval between applications. If rainfall is very slight and plant growth slow, you may wait up to 21 days before a new fungicide application is needed. Most commercial fungicides direct gardeners to reapply every one to two weeks, but in some rare cases this rule does not apply. Some fungi must be treated very specifically.

Molds

• Some garden molds require little fungicide treatment. Slime molds rarely need fungicide treatment, and when they do, more than one application is rarely necessary. Snow molds need to be treated with fungicide only once every eight weeks. Molds are very slow-growing, and some may be mechanically removed from garden areas and plants by hand.

How to Use Fungicide

• Always wear gloves when working with chemicals in the garden. Fungicide should be sprayed directly on plants, even non-infected areas, to protect leaves, stems and flowers from damaging disease. Use organic or safe fungicides on food crops, even if they have yet to begin fruiting. Spray fungicide on the soil around plants as well, as many fungi live in soil.