Feekes growth stages 9 (full flag leaf emergence) and 10 (boot stage) can be identified without having to pull plants from the field. At this stage, you are no longer looking for and counting nodes at the base of the stem. Once the wheat crop is beyond Feekes growth stage 8 (flag leaf emergence), you can simply observe tillers in the field to determine if the flag leaf is fully emerged (Feekes 9) or if the wheat spikes (aka the head) is swollen in the leaf sheath of the flag leaf (Feekes 10; commonly referred to the boot stage).
1- Examine primary tillers at multiple locations in the field – remove them if it makes it easier for you to examine;
2- Identify the flag leaf which is the fourth leaf about the lowest node on the stem;
3- If the flag leaf is fully emerged, then the ligule will be visible - the ligule is the whitish or light-green collar or flat found at the junction of the leaf blade and the leaf sheath;
4- If the ligule of the flag leaf is visible, then you are at Feekes 9;
5- If the flag leaf is fully emerge with its sheath fully extended and swollen (thicker than the rest of the stem), then you are at Feekes 10, the boot stage.
Click on the links below for information on management practices that are recommended (or not recommended) at these growth stages: