The Impact of a Late Spring Freeze on Wheat March 26, 2024 Facebook Twitter LinkedIn Email Earlier maturing wheat variety fields should receive priority scouting if a freeze occurs Wheat in boot-heading stages is most susceptible to freezing temperatures The lowest temperature reached and amount of time spent at those low temperatures are critical considerations After the recent temperature shifts, some may be questioning the impact of cold temperatures on wheat. This article will discuss potential issues associated with a spring freeze on wheat and what you can do to assess potential issues. Winter wheat is a crop that can tolerate cold temperatures during the early phases of its growth and development. From early developmental stages through tillering, this small grain can easily withstand temperatures of 12°F. However, as spring progresses and the wheat growth advances past stem elongation it becomes more susceptible to injury by freezing temperatures and the length of time those sub-freezing temperatures occur. This is because at jointing the growing point (meristem) is pushed above the soil surface and is no longer protected by the soil. Cold tolerance is reduced further from boot (28°F) through heading (30°F). The table below provides some detailed criteria for considering injury likely-hood, and symptoms to look for regarding sterility and poor grain fill. Table 1. The effects of freezing temperature on wheat yield, as impacted by growth stage. Information based on Spring Freeze Injury to Kansas Wheat https://bookstore.ksre.ksu.edu/pubs/c646.pdf Growth STage feekes approximate temperature for injury (2 hrs OF Symptoms Effect on yield Tillering 1-5 12 Leaf tip scorch, blue cast to fields Low Jointing 6-7 24 Leaf chlorosis, splitting of lower stem, death of growing point Medium/High Boot 10 28 Floret blanking, spike trapping, leaf discoloration Medium/High Heading 10.1-10.5 30 Floret blanking, white awns/spikes, leaf discoloration High Flowering 10.51-10.54 30 Floret blanking, white awns/spikes, leaf discoloration High Milk 11.1 28 White awns/spikes, leaf discoloration, shrunken/discolored kernels Medium/High Dough 11.2 28 Shriveled discolored kernels Low/Medium If your wheat has experienced injury from freezing temperatures, it will often show symptoms within 3-5 days. Areas that are most likely to be damaged are low lying areas of the field, or areas bordering forest edges or other sources of shade. Symptoms include discoloration in leaves, for example, yellow or light green at first, or turning darker green if heavily damaged. Warm temperatures in the days immediately following a freeze may result in rapid plant growth, causing wheat head distortion and twisted appearance. Also, secondary tillers may be permanently stunted and not produce as well as they would normally. If your grain was intended to be used for bread or seed for next season, it will be important to critically examine grain heads post-flowering. Kernel quality (or blank heads) and poor germination rates may result in the wheat being unacceptable for use in either purpose. It is unlikely that growers will experience a total crop loss, but the wheat’s overall revenue value and end purpose can certainly be greatly affected. Related Items Corn Replant Decisions Corn replant decisions can be complex, and many different factors should be considered prior to replanting a field. Read the full story Management of Fusarium Head Blight and Fungicide Timing Tips This article will go over the basics of Fusarium Head Blight (FHB) and management. Read the full story Weed Control in Cool Season Grass Pastures Weeds are prominent this year in many grass pastures. Late May to Early June is the best time to control many perennials, annuals, and woody plants. It is also important to remember that it's usually better to spray too early than too late. Read the full story