Volume 1 Issue
2 May
28, 2004
How Cold Is too Cold for Small Grains
to Develop?
The month of May will enter the record
books as the coldest ever recorded for the region. What
does this mean for crop growth and development? Well small
grains are cool season annuals. Wheat and barley really
don’t mind the current temperatures. Their development
just slows as fewer heat units are accumulated over time.
For comparison I looked at the accumulated growing degrees
and corresponding growth stage for wheat for two planting
days in 2004 and compared those numbers the previous three
years.
A quick review of the data shows that, for the April
planting date, we currently are about leaf to a leaf and a
half behind in development when compared to 2001 and 2003.
This difference equates to about 140 to 210 growing degree
days (GDD) or 3 to 4 days 800F days. For the May planting
date we are a half to one whole leaf behind in development
when compared to 2001 or 2003 or 2 to 3 800F days. We are
ahead in development of the crop when comparing to 2002,
but it should be noted that in 2002 a large portion of the
acreage was planted on a later date than the two dates
used in this example comparison.
Thus, no reason to panic - the crop is getting well
established, will have ample opportunity to tiller and
develop into an excellent crop.
Jochum Wiersma Extension Small Grains
Specialist
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