Growing Degree Day explaination

[gobbler]

Our local news some time ago started reporting Growing Degree Day units during the ag report.

Can someone explain how they come by those numbers and what they mean ???

Jim

 

[hazmat]

Its a measure of how mature a crop is. Check out this link <font color=blue><A target="_blank" HREF=http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/cdus/degree_days/gdd.html>NOAA Climate prediction center</A></font color=blue>

 

[gobbler]

Hazmat,

I read that same link before I posted too, I guess it's still not making sense to me.

I think it's basically that the warmer it is, (up to a point) stuff grows better.

 

[Anonymous Poster]

A Growing Degree Unit is the low plus the high (92 max) divided by 2 minus 50. For example a day with a low of 58 and a high of 74 would have 16 Growing Degree Units, (58+74)/2-50=16. Corn does not grow below 50 or above 92 degrees.

 

[gobbler]

Ok Tim,

Today in NE Missouri, the low was 71 and high is supposed to be 91. That would give us 31 GDD. Now is today’s 31 GDD, better or worse than your hypothetical 16 GDD in Minnesota ???

Jim

 

[Anonymous Poster]

Corn will grow almost twice as munch with 31 GGD.
A low of 71 and high of 91 is about as ideal day you can have.
Assuming their is enough groun mosture.