First hollow stem (FHS) is the optimal time to remove cattle from wheat pasture. This occurs when there is 1.5 cm (5/8” or the diameter of dime) of stem below the developing grain head (full explanation). To give you a point of reference, the average FHS date over the past 20 years at Stillwater is March 6.

The latest FHS results from Chickasha (Table 1) and Stillwater (Table 2) are listed below. Wheat stem elongation overall at Chickasha is starting to progress quickly now. As of March 6, 21 of the 31 wheat varieties (68%) have reached the 1.5 cm threshold, with 14 of those 21 varieties reaching the threshold on March 6. Stem elongation at Stillwater is moving, but not at the same pace as Chickasha. As of yesterday, March 8, only 18 of 56 wheat varieties (32%) have reached the 1.5 cm threshold.

Keep in mind that several factors influence the onset of FHS. These include the wheat variety, location, temperature, available moisture, level of grazing, and planting date (later sown wheat will typically reach FHS later). The First Hollow Stem Advisor and the updates we provide give an indication of the FHS stem conditions in a particular area. However, because of the number of factors that can influence when FHS occurs, we cannot stress enough the importance of checking for FHS on a field-by-field basis.

Table 1. First hollow stem (FHS) results by wheat, triticale, rye, barley, and oat variety collected on 2/20/18, 2/26/18, 3/2/18, and 3/6/18 at Chickasha. Plots were sown on 9/25/17. The threshold target for FHS is 1.5 cm (5/8” or the diameter of a dime). The amount of hollow stem for each variety represents the average of ten measurements from non-grazed plots. Varieties that have reached FHS are highlighted in red.

Table 2. First hollow stem (FHS) results by wheat variety collected on 2/27/18, 3/5/18, and 3/8/18 at Stillwater. Plots were dusted in on 9/15/18 and did not receive significant rainfall until 9/25/17. The triticale, rye, barley, and oat plots were abandoned due to emergence issues. The threshold target for FHS is 1.5 cm (5/8” or the diameter of a dime). The amount of hollow stem for each variety represents the average of ten measurements from non-grazed plots. Varieties that have reached FHS are highlighted in red.