How fast does corn grow?

With corn sidedressing just beginning and several days of wet weather for the week some may become concerned about getting the job done before the corn is too tall. In survey's late last week most of the corn was just emerging to V2-3. If we use the leaf collar method of describing corn growth we would like to be done before we hit the V6-7 stage.

Dr Nielsen from Purdue University has a guide for how many growing degree days it takes to advance the crop on collar stage. It takes approximately 82 GDD to grow a leaf collar. For the week of May 25 to 31 we averaged 15 GDD per day. In this case we will advance a growth stage every 5.5 days.

The other fact working for a longer sidedress period in 2009 will be that generally later planted crops do not have as much height to them. So a v6 in 2009 will be shorter than the same stage in an earlier planted year like 2008. We should expect a longer access period to get nitrogen on crops this year.