Wait to check wheat stands for winter damage

    While the last few weeks of colder-than-usual temperatures have certainly been unpleasant for people and animals, there is also some concern for the health of wheat stands. The risk and severity of cold damage to overwintering wheat is influenced by a number of factors and is difficult to predict in advance. In fact, until the wheat breaks dormancy and begins active growth in the spring, it is even difficult to tell if winter damage has occurred or not. Further complicating matters, during the winter and into early green-up, the appearance of leaves is not a reliable indicator of plant health or survival.
    Waiting until temperatures warm and wheat has been growing actively for a week or so is the best time to evaluate for winter damage. At this point, damaged plants will have had time to grow into any previously hidden injury, and healthy plants will be starting to grow out of leaf burn and other transitory damage. To evaluate health, dig up seedlings and check the crowns. When split with a fingernail, healthy crowns will be firm and white in color, with evidence of new root growth. Damaged crowns, on the other hand, are usually easy to pick out. They will often be wilted or dried out, and may have a watery appearance. The usual healthy white color may take on a translucent appearance or change to shades of grey or brown. Growth of new roots will not be evident and old roots will be shriveled, wilted or dead.
    If you are particularly concerned about winter damage or want to have some idea, measure before the weather warms up. The “bag test” can be used to check for damage in areas of special concern. The steps are as follows:
    — Carefully collect a representative sample of plants from across the area of concern. Dig plants out of the field with the surrounding soil in blocks at least three inches deep under the seed row.
    — Thaw soil chunks at room temperature and carefully wash the soil away from the roots with cool water.
    — Cut the leaves about one and a half inches above the crown and roots just below the crown. Rinse again with cool tap water.
    — Place five to 10 cut crowns per bag into a zip-close bag, inflate and seal. Crowns should be moist but not overly wet or in standing water, as this can promote disease and interfere with results.
    — Place the bag in lighted room in the house but out of direct sunlight.
    — After five to seven days, healthy crowns should show at least half of an inch of new root and/or leaf growth.

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