Determining Final Plant Stands in Corn

The corn crop in Manitoba is now planted and corn is emerging quickly!  Over the next few weeks is when producers should be evaluating their final plant stands as plants emerge and develop through early leaf stages.

Did You Hit Your Plant Stand Target or Miss it? 

To determine plant population or stand, count the number of corn plants in a row length equal to 1/1000 acre. Multiply that number by 1000 to get the number of plants per acre.  Do this several times in a field to get a representative sample.

  • In a 30-inch row spacing, count the plants in a 17’4″ row.
  • 20-inch row spacing, count the plants in a 26’1″ row.
  • 22-inch row spacing, count the plants in a 23’8″ row.

Now compare the final plant populations achieved to what you intended to plant, i.e. calculate your attrition losses.  If losses range up to 10% or more, investigate the reasons.  Was germination impacted by cold, wet soils? Did insects like wireworms or cutworms impact final plant stands?  Identifying the cause(s) behind the losses is important.  It can help determine whether changes in your planting operation or agronomic decisions may improve the odds of good stand establishment in the future.

Also keep in mind that corn that initially emerges and develops uniformly through early leaf stages can take a turn for the worse around the three- to four-leaf stage if the plant is damaged by insect or disease prior to the successful development of nodal roots from the crown area of the plant.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist


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