We have now turned the calendar to August and reached a point where an educated guess at corn maturity can be made.  To do this, growing degree units (GDU) can be used.  One of the "benchmarks" often cited regarding corn development is to have corn silking by the end of July.  In many cases, that happened but there is a lot variability between fields and WITHIN fields (typical of years when we have a lot of early season rainfall).  To reach physiological maturity (kernel black layer stage), it takes about 1100 GDU's.  On average, we can expect about 1073 GDU's from August 1st through October 11^th (our average first frost date).  Corn that silked within the past 1 to 2 weeks still has a good chance of reaching maturity.  Corn that has not yet silked will need some help in the form of above average temperatures or a late fall frost.  Regardless of corn hybrid maturity, it takes essentially the same amount of days/GDU's to progress from silking to physiological maturity. 

What about early planted corn for silage harvest? 

     Here again, we can use growing degree units (GDU) to make our predictions.  From silking to "full dent", or when corn reaches 65 to 70 percent whole plant moisture, it takes about 900 GDU's.  On average, we accumulate 900 GDU’s between August 1^st and September 20th.  Hence, corn fields silking this past week should be ready to chop sometime before September 20^th but probably not much earlier than September 10^th assuming we have near "normal" temperature and rainfall conditions.  This is a similar scenario to what we saw in 2004.  It will be important to monitor corn maturity on a field by field basis.  Again, there is also an extreme amount of variability in plant maturity within some fields. 

What about the late planted corn? 

     This is where the situation becomes a bit tenuous.  Clearly there is very little chance that later planted corn will produce much, if any, mature grain.  In some cases, no grain will be produced.  Farmers generally knew this when it was planted.  However, it will make feed and that translates to value.  The strategy this fall is simple:  wait for a fall frost and monitor whole plant moisture as the crop essentially dies.  This is not always as easy as it sounds because appearance can be deceiving.  That is, the crop often will look drier than it really is.