Late fall winterizer fertilization is the single most important feeding of the entire year for Ontario cool-season lawns. While top growth slows as temperatures drop, roots remain active underground, absorbing and storing vital carbohydrates.
Why Potassium is King in Late Fall
Winterizer fertilizers feature higher potassium (K) ratios. Potassium hardens cell walls inside grass blades and roots, acting like antifreeze to protect turf tissue against subzero frost and ice formation.
Optimal Application Timing in York Region
Apply winterizer fertilizer in late October or early November after top growth stops but before the ground freezes solid. This ensures roots absorb nutrients without sparking soft top growth that frost could burn.