The best time to plant grass seed depends on your local climate and whether you have cool-season or warm-season grass.
For cool-season grasses (like tall fescue), the ideal time to seed is late summer or early fall (typically August and September). During this period, the soil is still warm from the summer, but the air is cooler, creating optimal conditions for germination and root establishment before winter. There is also less competition from weeds. Spring is a secondary option, but cooler soil temperatures, the risk of a late frost, and less time for the grass to mature before summer heat can make it less successful.
For warm-season grasses (like St. Augustine), the best time to plant is from late spring through mid-summer (typically May and June), when temperatures are consistently between 75 and 90 degrees Fahrenheit.
In general, it is best to avoid seeding during winter or early spring, as cold soil and air can prevent seeds from germinating. For recommendations tailored to your specific grass type and climate, consider consulting a local lawn care professional.