Are you making a decision about cutting alfalfa in September? Consider reviewing these pointers from Marc Sulc, OSU Extension Forage Specialist:
Complete Article: Late Season Forage Harvest Management
Fall cutting risk can be reduced but not eliminated. Nature bats last and alfalfa stand health and survival will suffer more from fall cutting when when have early freezes, open and very cold winters, early springs with ice, and/or extreme rainfall and temperature variations. If at all possible, we urge producers to observe the fall rest period for forage legumes. And if you do harvest during the fall rest period, leave some strips of uncut forage to compare to. You might learn something useful!
From: https://agcrops.osu.edu/newsletter/corn-newsletter/2020-28/late-season-forage-harvest-management