Question
I am reseeding with perennial ryegrass, do I fertalize before or after reseeding?

Answer
Fertilizer is NOT good at this time of year for Seeding; it boosts growth way past the normal growth of the new Grass, and the new Grass doesn't have the physical requirements to support this new growth.  Your Soil should have been amended before you planted your Grass.  Top dressing with compost is a better idea; you won't have to worry about burning the Grass, and it will do wonders for a new Lawn.  Perennial Rye in particular will germinate in 7 to 14 days, depending on the Seed, the temps of Soil and air, variety and weather.  Good luck,

THE LONG ISLAND GARDENER