Understanding Alfalfa Winterkill: What to watch for

Authors: QUEIROZ, LUANA - University Of Wisconsin; KOHMANN-MOURA, MARTA - University Of Wisconsin; Siebers, Matthew

Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: 5/1/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: Alfalfa winterkill is an important cause of stand loss and reduced forage productivity in northern production systems. This outreach article explains the biological and environmental factors that contribute to winter injury in alfalfa, including plant hardening, crown health, soil conditions, ice sheeting, freeze-thaw events, and spring recovery. The article helps producers and agricultural professionals understand what conditions increase winterkill risk and what signs to watch for when evaluating alfalfa stands after winter. This article is intended as an educational trade publication and is not a first formal report of original research.

Technical Abstract: Winter injury and winterkill can reduce alfalfa stand persistence, forage yield, and long-term productivity in northern environments. This trade article summarizes major physiological and environmental factors associated with alfalfa winter survival, including fall acclimation, carbohydrate storage, crown and root health, soil drainage, ice sheeting, low-temperature injury, and freeze-thaw stress. The article also describes practical field indicators that producers can use when assessing alfalfa stand condition in spring, including delayed green-up, plant density, crown injury, and uneven stand recovery. The objective of the article is to provide forage producers, extension personnel, and agricultural stakeholders with a concise overview of winterkill risk factors and post-winter stand assessment considerations. The article is an outreach-oriented synthesis and does not report new experimental data.