Fertilizer
Cool-season fall nitrogen
Fall is the most important feeding of the year for Kentucky bluegrass, tall fescue, and ryegrass. Cooler air slows leaf growth while soil is still warm enough for active root growth, so the nitrogen goes into building deeper roots and denser tillering instead of fast top growth.
Shallow soil temperatures are in the action band at 59.4°F at the Mount Mansfield sensor, 14 miles from your location.
Window: Jul 29 to Oct 31. Window typically open for 2 to 3 weeks.
Why this, why now
- [10] University of Minnesota Extension: Fertilizing Lawns (2024)
- [11] Penn State Extension: Turfgrass Fertilization: A Basic Guide for Professional Turfgrass Managers (2016)
Dissent and uncertainty: UMN recommends mid-September application; PSU allows through mid-October. Registry uses the wider PSU window (Sep–Oct) to accommodate cities further south within the cool-season range.
Safety details (REI, air-temp ceiling, pre-rain)
Re-entry interval is not required for this product.
Air temperatures above 80°F can volatilize the product or stress the lawn. Wait for cooler conditions.
Air temperatures below 40°F slow uptake and reduce efficacy. Wait for warmer conditions.
Apply at least 24 hours before forecast rain so the product binds before runoff.