Apply the fungicide to your grass just as the weather gets hot in late spring. This is the peak time for fungi to begin their growth patterns. Complete the application in the evening after the temperature drops.
Spray on a fungicide to deal with the type of fungi you have in your grass. There are many different types, so if you're not sure, consult with a professional at your local home and garden store. Use an RTS, or ready to spray, fungicide for easiest application.
Water your grass only two to three times per week during cooler hours of the day. This helps prevent the fungicide from washing away and inhibits the growth of fungi.
Reapply the fungicide after 28 days if you see signs of fungi growing, or as often as the fungicide product you used recommends. Apply the fungicide three times a year to control the fungi.