Phosphorus free, formulated to prepare your turf for winter dormancy, special root-building formula contains essential nutrients that encourage stronger & healthier seedlings, contains slow release nitrogen for the extended feeding of your turf, apply in the fall to protect turf during winter & for a better lawn in the spring, generally beginning of september to mid november, northern zone, cool season grasses, beginning of september to end of november, transitional zone, & mid september to end of december, southern zone, warm season grasses.