The Importance of Planting Depth

We often hear that you should shallow up your planting to get seed out of the ground faster, or plant deeper to get to moisture.  That being said I have also heard that you don't need to worm sheep if you feed them oats, "it spears the worms" as one farmer back home used to say.  You tell me which one sounds the worst.  While there is some truth to planting deeper in times of extreme drought or when you work too far ahead of the planter, the other two sayings have little merit.

Plant variation from 1" planting depth

The name of the game really is uniform emergence and putting the seed in a place that will have little variation in temperature and moisture.  In the early spring these temperature swings are more likely as we often get those cold wet nights that will effect germination.  Later in the season getting seed out of the ground fast is not really an excuse, as soil temperatures warm up I have seen corn come out of the ground in less than 5 days planted 2.5" deep.  Corn plants will also set brace roots at the same distance from the crown whether it's 1/2" or deeper so often we will find brace roots set higher on shallow planted corn.  This can lead to brace roots burning off in dry soil conditions we often get in July and August.






So what is the ideal seed depth for corn?  I'd say 2" is still a very good number, and in worked ground you need to account for 1/4" of settling.  I often get the question, so where do I set my planter to get 2"?  The best thing we can do is get out and dig.  This depth will vary on down pressure, soil type, and planting conditions.  This is something I would recommend doing on every field and checking every time you get out to fill the planter.  I have seen all sorts of reasons this is a good idea.  In the past two years I have seen broken seed disks, missing gauge wheels, and many other things go wrong that were missed for several passes.  It's very hard to get a do over on one row across a field.

A seed firmer also helps with even planting depth to get every seed to the exact same depth.  A big problem I have seen with some types of row units is that with offset seed disks and RID (Reduced Interior Diameter) wheels is we get seeds hanging up in the side walls from the lower angle of the disks and air pockets left from the bulge in the RID wheels.  A firmer will often help with this, but not cure it entirely.  These are all reasons I have preferred setups for each area I work in.

So before you head to the field this year, consider planting depth and consistent planting depth while you work on your planter.  It's these little things that will determine if each corn plant is a good plant or a weed.