5
Zadoks Decimal Growth Stages
Feekes Large Growth Stages
Cereal Growth Stages
The Feekes and Zadoks scales define the growth
stages of a relatively uniform cereal crop. Completion
of these growth stages by the cereal crop will be
influenced greatly by soil temperature, moisture, air
temperature and day length. For example, stages 2 to
5
in the Feekes scale may take 5 or 6 weeks, whereas
stages 6 to 10 may be completed in 2 to 3 weeks
under prairie conditions.
To establish the growth stage of a cereal crop using
either of these scales, it is necessary to collect a
random sample of plants to determine the level of
growth attained by the majority of the plants.
Under good growing conditions, examination of up to
10
random selected plants may be appropriate. Under
conditions of uneven germination and low soil moisture,
growth stage assessment may require larger samples.
Application of an agrochemical must be timed
precisely to maximize the desired effect on the target
crop. All agrochemical applications (fungicides,
growth regulators, herbicides, or supplemental
nutrients) must be based on physiological growth
stage of the crop. Applications based on calendar
days are less accurate and will be less successful.