First Hollow Stem Update – 2/10/2022

Amanda de Oliveira Silva, Small Grains Extension Specialist

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 a dime) of hollow stem below the developing grain head (see full explanation). The latest FHS results from OSU forage trials in Stillwater(Table 1) and Chickasha (Table 2) are listed below. For an additional resource, see the Mesonet First Hollow Stem Advisor.

We use an accelerated growth system to report the earliest onset of FHS stage. Trials are seeded early to simulate a grazed system, but the forage is not removed. Varieties reported here with the earliest FHS date should be the first to monitor in commercial fields. In practice, wheat that is grazed will likely reach FHS stage later than reported here, and differences between varieties will likely moderate.

Table 1. First hollow stem (FHS) results for each variety collected at Stillwater. Plots were planted on 09/27/21 but not grazed or clipped. The threshold target for FHS is 1.5 cm (5/8″ or the diameter of a dime). The value of hollow stem for each variety represents the average of ten measurements. Varieties exceeding the threshold are highlighted in red.

Table 2. First hollow stem (FHS) results for each variety collected at Chickasha. Plots were planted on 09/28/21 but not grazed or clipped. The threshold target for FHS is 1.5 cm (5/8″ or the diameter of a dime). The value of hollow stem for each variety represents the average of ten measurements. Varieties exceeding the threshold are highlighted in red.

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About Amanda De Oliveira Silva

I joined Oklahoma State University in 2019 as an Assistant Professor and Small Grains Extension Specialist and was promoted to Associate Professor in 2025. My program integrates applied research and Extension with the goal of improving the productivity, profitability, and sustainability of wheat production systems. While much of my work is rooted in Oklahoma and the Southern Great Plains, the questions I study—how agronomic management, crop physiology, and plant nutrition interact to influence yield, grain quality, and nutrient use efficiency—are relevant to wheat-growing systems around the world. By working closely with producers, industry partners, and researchers, my goal is to develop practical, science-based solutions that help growers navigate production challenges and improve the resilience of their farming systems.

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