If you are planting grass seeds that have not been treated with fungicides, you should treat the soil at the time of seeding or soon thereafter. Follow the manufacturer's instructions for the timing and rate of application of the fungicide.
About the Author
Melody Lee holds a degree in landscape design, is a Florida Master Gardener, and has more than 30 years of gardening experience. She currently works as a writer and copy editor. Her previous jobs include reporter, photographer and editor for a weekly newspaper.